hessmarine.ca

marine engines & marine equipment

go to Main Menu page

Atomic Four Marine Engines - Frequently Asked Questions (FAQ)

What size propeller should I use on my Atomic Four engine?

The boat must be fitted with a properly balanced propeller of a pitch and diameter that will allow the engine to reach rated rpm for a few minutes during full throttle / top speed testing in normal conditions with a normal load.  Atomic Four engines fitted with a reduction gear box, must be able to reach maximum rated engine rpm of 3,500 rpm, while direct drive Atomic Four engines, both direct drive Atomic Four and direct drive Atomic Four Stevedore engines (whether fitted with the Stevedore intake manifold restrictor or not), must be able to reach about 1,800 to 2,100 rpm. If the engine cannot reach rated rpm the propeller is too large and must be replaced with one with a smaller pitch and/or diameter. The use of a propeller that restricts engine rpm to below specification at full throttle will create a lugging condition that will cause engine overheating and damage (ie blown head gaskets). 3 blade propellers are usually recommended for cruising boats in areas with strong currents and tides, while 2 blade propellers are usually used on boats primarily used for racing. Both 3 blade and 2 blade fixed-blade propellers can be "parked" with at least 1 blade in a vertical position which will allow it to be shielded by the shaft strut or keel, allowing slightly more speed under sail.

Should I install a water separator fuel filter assembly?

Many marine engine problems are caused by water condensation in fuel tanks, and water / dirt transferred from marine fuel depot (ie marina) fuel tanks. Clean fuel is just as important to gasoline engines as it is to diesel engines, and a water separator filter/fuel filter should be fitted to boats with Atomic Four gasoline engines. Gasoline engine water separator filters should not be fitted with a glass sediment bowl or bowl drain petcock (the bowl drain must be a screw-in plug). Fuel filter elements should be changed at least annually, preferably in the autumn. We recommend the Racor 320R-RAC-02 filter assembly for Atomic Four and Atomic Four Stevedore gasoline engines. Primary water separator filters should not use a filter element finer than 10 microns (ie do not use 2 micron elements on the primary filter) because it can cause fuel pump damage.

What oil should I use in my Atomic Four marine engine?

Type:
non-synthetic

API rating:
SG or SG equivalent

Viscosity:
Average temperature under 10°C / 50°F: SAE 10-40
Average temperature over 10°C / 50°F: SAE 20-50

Use only the motorcycle oils listed below in order to prevent forward clutch slip while providing maximum engine protection and optimum piston ring break-in. All the oils listed are available in both 10-40 and 20-50 viscosities. We use Castrol Grand Prix 20-50 4-Stroke Motorcycle Oil in the summer.

Castrol Grand Prix 4 Stroke Motorcycle Oil (available in 1 litre cans in Canada)
Shell Advance SX4 Motorcycle Oil  (available in 1 litre cans in Canada)
Valvoline 4-Stroke Motorcycle Oil (not sold in Canada)
Belray EXL Motorcycle Oil (comes in US quarts only - not available in full -size 1 litre cans in Canada)
Pennzoil Motorcycle Oil (comes in US quarts only - not available in full -size 1 litre cans in Canada)
Quaker State 4-Cycle Motorcycle Oil (comes in US quarts only - not available in full-size 1 litre cans in Canada)

Notes: Never use ANY oil additives. Do not switch brands. Do not overfill.

Should I add supplements to my oil?

No. Modern engine oil already has lots of additives, including detergents, dispersants, corrosion inhibitors, antioxidants, viscosity-index improvers, extreme-pressure additives, and 28 other chemicals. Do not add any oil supplements (ie Slick 50, STP, Marvel Mystery Oil, kerosene, diesel fuel, automatic transmission fluid, rotten bananas, etc) to the oil. Oil supplements can damage the engine, and can also cause integral clutch-type transmissions such as the Paragon transmission used in the Atomic Four to slip under full load. If you feel the need to add an oil additive product to the oil to free up suspected stuck rings or valves, try using 5-30 oil and changing it several times after approximately 10 hours of running. You can also buy a can of Engine Flush at an auto parts store and add it to the oil to flush the engine just before changing the oil. Stuck valves are usually caused by cold running or a leaking head gasket or a bad exhaust design allowing water to backflow into the manifold and exhaust ports from the water injection elbow, so before assuming valve problems are oil related, make sure the thermostat is bringing the engine up to the correct temperature: 140° F for raw water cooled engines running in salt water, and 180° F for engines equipped with heat exchangers, and that the head gasket and exhaust riser are in good condition and properly installed.

Go to www.chris-longhurst.com/carbibles/ for more information.

Should I add supplements to my fuel?

No. Modern engine fuel already has lots of additives: N-hexyl and octyl nitrate in diesel fuel, and anti-knock agents, scavengers, phosphorous additives, antioxidants, metal deactivators, surface-active agents, deposit control additives, deicing agents, dyes, octane boosters plus 43 other additives in gasoline. Adding any type of oil to the fuel dumps unnecessary oil in the water with the exhaust in the same way a 2 stroke outboard does. The Champion spark plug company "Spark Plug Handbook" warns "Champion does not recommend the use of fuel additives which leave deposits on the core nose of the spark plug". Under the heading "Splash Deposits" the Champion handbook states "the use of fuel additives, carburetor, and choke cleaners or other aggressive solvents before installing new plugs is the most common cause of this condition [splash deposits]", and under the heading "Fuel Additives" it states "red to purple deposits on one side of the core nose are an indication of fuel additives. While many of these deposits are non-conductive and do not contribute to lack of performance, some fuel additives contain octane boosters that leave conductive deposits on the core nose". Diesel secondary (final) fuel filters are so fine that they have been known to plug up with some fuel additives and cause engine failure. Do not add anything to your fuel tank except when you're putting the boat in winter storage, at which time you may want to add a small amount of gas line antifreeze to gasoline and diesel fuel conditioner to diesel fuel.

Go to www.chris-longhurst.com/carbibles/ for more information.

Atomic Four engines fitted with direct drive marine gears use a ball bearing with a "Z" designation for the rear thrust bearing. Can I use a regular ball bearing without the shield?

The Z designation in the bearing model number means the bearing has a shield on one side of the race. Shields are non-contact metal or plastic covers which allow for high speed operation by restricting (not stopping) the oil spray in the gearbox from flooding the bearing. They also help keep large bits of dirt and metal from getting into the bearing. The Atomic Four rear thrust bearing is also fitted with a shield to restrict (not stop) oil flow to the output shaft oil seal  which is located adjacent to the bearing. Fitting a bearing without a shield allows the full volume of oil spray to reach the bearing and seal, which can cause the bearing to receive too much oil and the rear flange seal to leak.

The original  bearing should be installed with the shield facing the front of the engine. Replacement bearings with shields on both sides can be installed with both shields left in place.

What is a rebuilt engine?

A rebuilt engine is an engine that has had most of the larger lumps of rust scraped off with a paint scraper, some of the dirt and salt washed off with a garden hose, the crack in the cylinder head patched with JB Weld, everything (including the spark plug leads and flame arrester air intake ) painted any old colour with left-over cans of house paint, the old oil topped up with a mixture of Marvel Mystery Oil and STP, fitted with lawn mower spark plugs and 4 foot spark plug wires from an old V8 Chevrolet, a cheap gate valve installed in the thermostat bypass hose, initially started with a spray can of starting fluid after sitting outside with a tarp over it for several years, and advertised as "...completely rebuilt Universal Atomic Four engine, fresh-water cooled, like new, 2 year warranty, see it running, call Midnight Marine Supply - pager 999-9999"...

No, actually a rebuilt engine is an engine that has been completely disassembled, professionally stripped in industrial acid and hot tanks to remove paint, oil, dirt, cooling system / water jacket deposits, and then measured, machined, and reassembled with new parts so that all clearances are within the manufacturer's tolerances, and all normal wear parts such as seals, bearings, gaskets, filters, hoses have been replaced. At a minimum, rebuilt engines should have the valves and valve seats ground using valve and seat grinding machines (not grinding paste), the cylinder bore ridge removed, the cylinder bore honed to a cross-hatch finish, the piston rings replaced, and the crankshaft bearings replaced. The engine cylinders should be rebored or sleeved and new pistons fitted if the cylinder bore is worn beyond manufacturer's tolerances.

My friend says when an Atomic Four engine is being rebuilt it should always be bored to the next oversize and fitted with new oversize pistons. Is he right?

No. Pistons for Atomic Four engines are expensive, and since most engines were raw water cooled and all engines are now at least 20 years old, corrosion in the water jackets may have reduced the thickness of the cylinder wall. Boring the cylinders oversize may reach a small pinhole caused by corrosion to cause a coolant leak into the cylinder. If the cylinder bore is worn beyond the limit for diameter, taper, or ovality, it is usually better to install cylinder liners, which will retain the original cylinder wall thickness and may allow the use of the old pistons (if the ring lands are still in good condition) because the new liners can be sized to compensate for any piston skirt wear, and thus return the cylinder/piston clearance to the original specification.

In most cases used pistons can be re-installed if the ring lands are in good condition and the cylinder/piston clearance is less than .005" as long as new rings are fitted and the cylinders are properly ridge-reamed and deglazed.

My friend works in an automotive machine shop, and she says that when any engine, including an Atomic Four engine, is being rebuilt the pistons should be installed with the arrow mark and "-> Front" stamp on the piston crown pointing to the front of the engine... the front on an Atomic Four being defined as the flywheel end, not the marine gear/propeller shaft coupling end. Is she right?

No. It is common for automotive engine rebuilders to install Atomic Four pistons facing in the wrong direction, because they assume the "-> Front" mark on the top of the original OEM pistons means they should be installed facing what would be the front in an automotive engine, when in fact the "-> Front" mark should face towards the marine gear / propeller shaft end so that the vertical expansion slot and piston pin offset are in the right position. Installing the pistons backwards causes mysterious oil consumption problems.

My friend says when an Atomic Four engine is being rebuilt the camshaft bushings must always be replaced. Is he right?

No. In order to properly clean an engine for rebuilding it must be cleaned in an industrial "hot tank", which requires that the camshaft bushings be removed (to prevent them from being damaged by the caustic cleaning solution) and then reinstalled and line reamed as part of the assembly process. Atomic Four camshaft bushings wear very little unless the engine has experienced a lubrication failure at some time in the past, and because they are expensive it is considered cost-effective to re-install them even when the engine is being completely rebuilt and all other bearings are being replaced.

Do I need a tachometer for my Atomic Four?

No, a tachometer is not essential, although it is a popular accessory. A tachometer should be used initially to verify the correct propeller has been fitted, but once that is done engine speed is limited by maximum boat speed, and is directly linked to the boat speed shown by the boat knot meter, so a tachometer is not essential. Tachometers are used in land vehicles to determine the correct engine rpm for gear shifting, however since most marine engines have only 1 forward gear, the only use for a tachometer is to check engine performance and/or hull and propeller condition. Engine speed may be higher than normal in case of transmission clutch slip, a sheared propeller shaft flange or propeller key, a damaged diesel engine governor, or a damaged propeller, however excessive engine speed will quickly be recognized by a marked increase in engine noise and vibration.

How do I pick the right gauge and gauge sender?

Most electrical gauges except voltmeters and ammeters work in tandem with a variable resistance gauge sender. In order for the gauge to read correctly, the sender has to be matched to the gauge. There is no industry standard gauge sender resistance, and each manufacturer uses their own specification and design, so gauges and gauge senders from different manufactures usually are not compatible. As well, each manufacturer makes different resistance gauge senders for boats with single station controls and for boats with dual station controls (1 sender connected to 2 gauges) which cannot be interchanged. The wrong sender can instantly destroy a new gauge, or fail to warn the operator of an engine problem. For those reasons it is recommended that oil pressure, water temperature, exhaust temperature, manifold vacuum, fuel pressure, water pressure, etc. gauge senders be replaced at the same time gauges are replaced.

Cheap gauges usually work OK for a while, but are usually are not properly designed to withstand the vibration and corrosion inherent in marine use and break just when they're needed. The flimsy mounting systems on cheap gauges usually cause more lost time than was saved in not buying a quality product too, as well as causing a lot of problems with loose gauges and wires. For those reasons, and more, we only sell Stewart Warner (SW) marine gauges and senders, because we find that their initial higher cost is more than compensated for by their faster installation, reliability and accuracy.

Are Atomic Four engines dangerous because they use gasoline for fuel?

No. Gasoline vapour is highly inflammable and can cause an explosion if it ignites in a closed space like the engine compartment or cabin of a sailboat, however if the fuel system is properly installed, the engine and fuel system receive regular maintenance, and the operator follows Canadian Coast Guard safety procedures when refueling, gasoline causes few problems. We are only aware of one Atomic Four gasoline vapour explosion which caused a fatality (in Montreal several years ago), despite the fact that there are thousands of Atomic Four equipped sailboats still in use. There are also thousands of inboard/outboard motor boats fitted with gasoline engines in use too (ie Mercruiser), and although explosions and fires are not common, they happen frequently enough to keep Atomic Four owners nervous.

The propane gas used on many boats for cooking and heating is similar to gasoline. Both gasoline and propane vapours are explosive and heavier than air, and so collect in the lowest part of the boat, which is usually where the engine is located. The Canadian Coast Guard Fire Safety Pamphlet suggests that inflammable vapours are usually ignited during starting by the spark created when the starter bendix gear hits the flywheel ring gear, so even though diesel engines do not have an ignition system which creates a spark like those used on gasoline engines, diesel powered boats fitted with defective propane systems are just as susceptible to an explosion during starting as gasoline powered boats with a defective fuel system.

Gasoline engines like the Atomic Four are perfect for coastal cruising because they are smooth, quiet, and easy to maintain. They're also free of the nausea inducing smell of diesel fuel (important if there are children on board) and it's easy to find fuel because gasoline is a standard fuel everywhere. For off-shore cruising the diesel engine is the best choice because of it's range and reliability (if it's properly maintained).

Is it a good idea to convert my raw water cooled Atomic Four engine to fresh water cooling by fitting a heat exchanger?

Yes. The cast-in water jackets in the cylinder block, cylinder head, and exhaust manifold of raw water cooled engines run in salt water are gradually being corroded by the salt water even when the engine is stopped, and plugged by the minerals and salts precipitated out of the hot water as the engine is run. Usually the first problem that occurs is overheating because the partially plugged water jackets restrict the flow of cooling water, and then later the engine block, cylinder head, and exhaust manifold begin to corrode through until they are so weak small leaks or cracks develop. Although cylinder heads and exhaust manifolds can be replaced, it is very expensive to replace the engine block itself (Atomic Four engine blocks are no longer available). The cost of all the components necessary to convert an engine to fresh water cooling is approximately $900, and although the conversion is expensive, it is one of the few modifications you can make to your engine that will actually increase the value of the boat, since it is quite common to see a boat with a fresh water cooled engine advertised at $500 to $1,000 more than the same model/year/condition boat with a raw water cooled engine.

When a raw water cooled engine is converted to fresh water cooling, the existing water pump (usually driven directly off the engine from an engine auxiliary drive) is usually used as the engine coolant pump to pump the water/antifreeze coolant through the engine, to the heat exchanger, and back to the engine. 2 types of heat exchanger can be used, a horizontal engine mounted heat exchanger mounted over the exhaust manifold or at the rear of the engine over the marine gear, or a vertical remote heat exchanger mounted on an adjacent bulkhead. Universal diesel engines after the Model 5416 were equipped with fresh water cooling as standard equipment, with the sea water pump driven by a power take-off on the front of the engine. The engine coolant pump on these models is a centrifugal belt driven automotive type water pump. Universal Atomic Four engines were available with an optional fresh water cooling system which used a horizontal heat exchanger mounted over the exhaust manifold and a rubber impellor sea water pump mounted over the starter and driven by a belt from a pulley on a power take-off assembly mounted on the front of the flywheel. Aftermarket heat exchanger kits mount the sea water pump in various locations: over the starter in the same configuration as the OEM system, over the alternator and driven by a longer alternator belt which also still drives the alternator, directly off the front of the engine using a rubber cush drive assembly, and an electric pump mounted in a convenient location near the engine or heat exchanger and used as an engine coolant pump so the original rubber impellor pump can be used as the sea water pump (electric pumps have a hard impellor which must only be used with clean coolant... and because they are not fitted with a rubber impellor they are not self-priming, which is a requirement for any sea water pump.

We recommend the OEM factory sea water pump configuration, which is a sea water pump mounted over the starter and driven by a belt running off a PTO mounted on the end of the crankshaft. This configuration requires 3" clearance in front of the engine flywheel cover, which in many cases can be obtained by cutting a bit out of the engine cover, or remounting the engine cover/cabin stairs slightly forward. The factory installation also had a horizontal heat exchanger mounted over the manifold, however some smaller sailboats do not have room for this and a horizontal or vertical heat exchanger must be mounted on an adjacent bulkhead. The OEM sea water pump was a Sherwood R30G...we use a similar pump... a Jabsco, because the Jabsco is cheaper, easier to get parts for, and easier to service. This arrangement is much superior to any other configuration except direct mounting the sea water pump on the end of the crankshaft (which requires space for the pump and rubber cush drive... about 8"... usually only available on engines fitted with V drives where the engine faces the stern) because it allows for easy access to the pump, doesn't require that the stock alternator belt carry the extra load of a water pump (and therefore allows the stock 35 amp alternator to be replaced with a higher output alternator without increasing the belt width (there is limited clearance for a pulley larger than the stock auxiliary drive pulley... and 90 amps is the limit for the stock belt). If you order a fresh-water cooling system installed during an engine rebuild we will mount the heat exchanger on the engine in the OEM configuration (longer manifold studs are fitted to all rebuilt engines to allow for heat exchanger mounting). If you find that the engine cannot be installed with the heat exchanger in that position, it is a simple matter to remove it from the engine and install it on an adjacent bulkhead (a couple of longer coolant hoses may be required... use automotive heater hose available from any auto parts store).

How do I adjust the ignition timing on an Atomic Four engine?

The ignition timing on an Atomic Four engine can be adjusted in several ways, but no matter which method is used, before the timing is adjusted the distributor should be serviced to make sure the distributor shaft bushings are lubricated with light oil (a few drops of oil on the little piece of felt under the rotor) and not worn beyond specification, the centrifugal ignition advance is properly lubricated and working smoothly, and the contact breaker (points) gap is adjusted to specification using a feeler gauge, or a dwell meter if one is available. Once this is done the engine can be timed.

Static timing can be carried out by turning the crankshaft so the piston for #1 cylinder is at the very top of its stroke (TDC) with both valves closed (firing #1 cylinder), the distributor rotor is pointing at the distributor terminal for #1 spark plug, and the distributor points are just beginning to separate. You can connect a battery powered light or buzzer across the points to determine exactly when they open. When #1 cylinder is at the top of its stroke the split pin in the front of the crankshaft will be pointing straight up and down.

Dynamic timing can be carried out by either tying the boat firmly to the dock or taking it out an area where it can be run at top speed for several minutes, connecting a tachometer to the engine, slightly loosening the distributor clamp screw, opening the throttle to get maximum engine speed, gradually rotating the distributor back and forth until the engine is running at the highest rpm possible, and then retightening the distributor clamp screw. At full speed the engine should reach at least 2,100 rpm (if it can't, see "What size propeller should I use?" above).

How do I adjust the carburetor on an Atomic Four engine?

Early model Atomic Four engines were fitted with a cast iron Zenith 61 carburetor with 2 adjustment screws, one for the high speed main jet, and another one for the low speed idle jet. Atomic Four engines after 1968 were fitted with an aluminum alloy Zenith 68 carburetor with a fixed high speed main jet (some Zenith 68 carburetors have had adjustable main jets installed), but the same adjustable low speed idle jet as the Zenith 61. Assuming the flame arrester is not partially blocked by dirt and oil, and the carburetor is clean and in good condition with the float level set properly, the proper procedure is as follows:

Carburetors with fixed high speed main jets should have the main jet removed and checked to see what jet number it is. The jet number is stamped in very tiny numbers on the face of the jet. If it is not a #21 main jet, it should be replaced with one.

To adjust the idle mixture screw, initially adjust the idle mixture screw (the upper adjustable jet with the slot for a screwdriver) clockwise (in) until it bottoms lightly, and then out 1 turn. Connect a tach to the engine, start the engine, run the engine in gear until it is fully warmed up, then close the throttle, leave the engine in forward gear, and adjust the carburetor idle speed screw (the screw on the carburetor throttle arm that controls the throttle stop) until the engine is idling at 700 rpm, turn the idle mixture screw slowly out until the rpm drops noticeably, and then in again until the fastest idle speed is obtained. Readjust the idle stop screw to again set the idle speed at 700 rpm. Repeat the idle mixture adjustment again.

Carburetors with adjustable high speed main jets should be initially adjusted by turning the main jet adjusting screw (the lower adjustable jet with the little cross on the adjustment screw) clockwise (in) until it bottoms lightly, and counter-clockwise (out) 3 turns, and the idle mixture screw (the upper adjustable jet with the slot for a screwdriver) clockwise (in) until it bottoms lightly, and then out 1 turn. Connect a tach to the engine, start the engine, and with the boat running at top speed in forward gear (or tied to the dock) slowly turn the high speed mixture screw clockwise (in) until maximum rpm is obtained on the tachometer and then counter-clockwise (out) about 1/8 of a turn until the rpm just starts to drop.

Close the throttle, leave the engine in forward gear, and adjust the carburetor idle speed screw (the screw on the carburetor throttle arm that controls the throttle stop) until the engine is idling at 700 rpm, turn the idle mixture screw slowly out until the rpm drops noticeably, and then in again until the fastest idle speed is obtained. Readjust the idle stop screw to again set the idle speed at 700 rpm. Because the idle mixture setting has an effect on the main jet setting, repeat the main jet adjustment, and then the idle mixture adjustment 2 more times.

The rationale for setting the idle speed at 700 rpm in forward gear is to ensure the engine is idling fast enough to prevent stalling or erratic running when docking. An engine speed of 700 rpm in gear will also automatically increase to about 800 rpm when the transmission is shifted to neutral, which is high enough to allow the alternator to continue charging the battery.

Some people say the Atomic Four takes 2 head gaskets, and some say it only takes 1. Who is right?

Both are right. The original Atomic Four head gasket was a single thick metal (copper?) gasket. Later the specification was changed to 2 thin composition head gaskets (Universal #23776), until Westerbeke released a new graphite gasket (Westerbeke/Universal #200452) in 1996. The technical bulletin released with the new gasket specifies only 1 of the new gaskets is required, however the manufacturer of the gaskets, Victor Gasket, specifies that 2 of the gaskets are to be used, as do several American Atomic Four specialists (ie Don Moyer). Our tests suggest that 1 graphite gasket works fine, however 2 gaskets probably work well when the cylinder head gasket surface has been machined several times because using 2 gaskets helps lower the compression ratio slightly, which is a good thing in flathead marine engines like the Atomic Four. We recommend always using 2 gaskets when the cylinders have been bored oversize (to either .010" or .020"), or when the head has been machined to eliminate any warp. Refer to Universal Service Bulletin 223 for more information.

There are a lot of accessories available for the Atomic Four. Which ones should I buy?

Many people will spend a lot of money on cheaply made accessories for their boat and marine engine, but skimp on basic maintenance and regular overhauls. We recommend purchasing a heat exchanger and suggest the Indigo Electronics PCV valve kit is a good short-term fix for an engine that needs a ring job and is smoking up the cabin, but don't recommend an accessory oil filter, an electronic ignition, or an adjustable thermostat bypass valve.

Accessory oil filters are not full-flow filters which filter all the oil before it is pumped to the bearings like the type used on cars, but are bypass filters which filter a small portion of the oil at a time. Changing the oil regularly achieves the same thing, without the possibility of the external oil lines to the accessory oil filter breaking or leaking, and causing massive engine damage.

Electronic ignition is not required on a slow-running engine like the Atomic Four, since the standard points and condenser can easily produce enough voltage to fire the spark plugs at any speed and load. As well, since the distributor cap must be removed on a seasonal basis for lubrication of the shaft and advance mechanism, it is a simple matter to install a new set of points and a condenser at the same time.

An adjustable valve installed in the thermostat bypass hose makes the Atomic Four have that "vintage" engine look, but is completely unnecessary if a functioning thermostat of the correct temperature rating to suit the engine is fitted to a properly tuned engine that has reasonably clean water jackets, a properly functioning water pump, and (in the case of a post 1968 Atomic Four) a thermostat housing with a bypass port boss which is in good condition. If there is a need to restrict the bypass hose with an adjustable valve to prevent overheating, the engine and/or the thermostat or thermostat housing should be repaired/replaced.

How should I prepare my inboard marine engine for below freezing temperatures?

Boats sink on the first warm day of spring because the owner made 2 mistakes at the same time. He/she failed to close the engine sea water through-hull sea-cock when the boat was left for the winter, and water was allowed to freeze in the sea-water side of the engine cooling system, which ripped a section of the sea-water hose or cracked an engine cooling system component. Once the ice melted it allowed sea-water to flow into the boat through the open valve and the damaged hose or component.

Remembering to close the sea-cock but failing to properly freeze-proof the engine will likely mean only massive engine damage and not a boat full of cold water too.

If you live in a place where there is any chance the temperature could go below freezing during the winter, you need to freeze-proof your engine before winter weather arrives to make sure the engine and components are not damaged by freezing temperatures. There are 3 ways to ensure water can't freeze in the cooling system and crack or distort engine components. You can drain all the water out of the cooling system so there isn't any water to freeze, you can circulate antifreeze through the cooling system so the water in it can't freeze, or you can use heaters to keep the engine and cooling water system warm enough so they don't freeze.

Draining: Even if drains can be opened without snapping off a seized drain plug, they frequently are hard to get at, and they quite often get plugged up with bits of rust and dirt which stop the flow of water when they are being drained, giving the impression the component is empty when it is not. If water is not completely drained from every section of the cooling system it can cause freezing damage in one or more individual sections which may not be evident until years later when the component fails.

Adding antifreeze: The optimum solution for maximum engine antifreeze protection (good to -60C) is 60% ethylene glycol antifreeze and 40% water. In order to ensure an engine cooling system is properly protected the antifreeze solution must be circulated to every part of the engine water jackets, heat exchanger, water lock exhaust or water jacketed exhaust pipe, and sea-water intake valve, strainer, and hoses. Because it is possible for the antifreeze to reach only some of the engine water jackets unless the engine is fully warmed up and the thermostat has opened, it is necessary to rig up a system to recirculate the antifreeze solution through the engine while the engine is running while the engine grows hot enough for the thermostat to open, or to remove the thermostat before circulating the antifreeze.

Heaters: Heaters work well, as long as they are capable of maintaining the engine, engine coolant hoses, exhaust system, and through-hull valve at a temperature higher than freezing, and as long as nobody pulls the plug or causes a power failure. In latitudes north of Florida using a light bulb for a heater is asking for trouble, since the light bulb doesn't put off enough heat to prevent freezing damage when temperatures start to go below -10 C. If a heater is going to be used, make sure it is connected to a temperature switch so it will turn on automatically when the temperature drops close to freezing, and that it can actually keep the engine and coolant/exhaust system warm. Ensure that the power supply is very reliable, and that a backup heater is available.

A friend told me that Atomic Four engines sometimes have erratic oil pressure, and there are several ways to fix the problem. What is he talking about?

Erratic Atomic Four oil pressure is a problem caused by Universal's change of the adjustable oil pressure regulating valve internal parts to a spring and 3/8" ball from a spring and pencil-shaped plunger around 1965 - 67. The 3/8" (.375") ball was not as good at controlling the oil pressure as the old spring and pencil-shaped plunger so they started using a larger 7/16" (.438") ball around 1972. This still didn't always work, and so they released a retrofit kit which was actually the old spring and pencil-shaped plunger. The kit was accompanied by a service bulletin titled "Atomic Four - Installing Oil Pressure Plunger Kit #256575" which is in the Atomic Four Parts Manual on page 98A/B and details a procedure called "seating plunger or ball" which can be used to improve the performance of the existing ball or when a pencil-shaped plunger is installed.

We don't follow this procedure ourselves, and we don't find replacing the ball with an plunger necessary... instead we use a special tool to cut the seat to obtain a new smooth surface at a slightly different angle, and then we fit a new 7/16" ball.

Dangerously high oil pressure (ie over 60 psi) when the engine is first started in cold weather means the oil is so thick that the oil pressure relief valve cannot handle it, and the oil should be replaced with a lower viscosity type.

Once you've got the ball or plunger installed and seated, adjust the oil pressure to 35 psi at cruise speed rpm with the engine hot.

A friend told me that there is no difference in operating an Atomic Four engine and a diesel marine engine, and top speed on boats fitted with either type of engine is obtained by moving the throttle lever all the way to full open and leaving it there. Is he right?

No. Unlike diesel marine engines the Atomic Four does not have a governor, and so the operator has to set the throttle manually (and keep adjusting it) according to the forces acting on the boat (ie head winds) at a setting which gives a maximum of about 90% maximum boat speed, (assuming the propeller is the correct size). Since top speed is determined by hull waterline length, and no amount of horsepower can get the boat past it, once the boat is close to hull speed all any extra throttle does is overload (lug) the engine. To determine the correct throttle setting for maximum cruising speed, open the throttle wide open for a few minutes and record the boat speed from the knot meter (or GPS). Then after that use only enough throttle to run at about 90% of the top speed obtained with wide-open throttle. For example if the maximum speed of the boat is 6 kn, then open the throttle only far enough to give a cruise speed of around 5 kn.

A friend told me that low engine operating temperature is a sign of a defective thermostat. Is he right?

Sometimes it is. Low engine coolant temperature which persists after the engine has been run under load for an appreciable length of time means either a missing thermostat, a defective gauge/sender, or (in cold water) a sticky or poorly sealing thermostat. You can check the actual water temperature by holding a portable surface thermometer against one of the middle cylinder head studs. It will read the real cylinder head water temperature, which is the temperature the gauge should read if the gauge and sender are properly calibrated and working correctly.

The large single spring fitted to the new Atomic Four thermostat supplied by Westerbeke has less pressure than the 3 small springs used on the OEM Holley thermostat originally fitted on engines made after 1968. If there is any restriction in the bypass line and/or a higher pressure Oberdorfer M7 (full cam) water pump has been fitted, the pressure developed by the water pump will actually overcome the force of the spring and open the thermostat slightly when the engine is cold. This can cause the engine to take longer than usual to warm up to operating temperature, as well as causing engines being operated in very cold water to run colder than the rated thermostat temperature.

How do I measure a used crankshaft to make sure it will fit my engine?

A crank or rod is more likely to break if the engine is over-revved in neutral rather than if the prop is too big; ie the boat is running in neutral and the throttle cable breaks or jams (or somebody steps on the throttle lever... which promptly breaks off in the wide-open position!), so the carb goes to full throttle and the engine tries to imitate an out-of-control chainsaw.

If you're checking a bunch of used cranks to see if you can find a good one, you don't want to have to install each one in a block and check the clearance with plastigauge, that could take a lot of time and require carrying a block around... and you could get a plastigauge measurement over .0025" (the maximum bearing clearance specified by the factory) on a good crank if a main bearing cap is oval and the block actually needs to be line bored, or if the crank is good but the bearing insert is worn.

You can quickly check to see if the crank journals have been damaged from wear or a seized bearing by scraping them with a small piece of copper (a penny will work). If any copper wears off on the journal it is not smooth enough, and must be reground. If there are any nicks or rough spots that also means the crank must be reground.

If the journals pass the penny test, then measure each one with a micrometer, taking at least 4 measurements... 2 at one position on the journal at each edge, and another 2 more at 90 degrees to each other on each edge. That way you can tell if the journal is worn oval or tapered, and you can also tell if the crank has already been ground undersize (a lot of people think that Atomic Four cranks tend to break if they're ground undersize, and will only use a crank with standard size journals... I'm not one of them, the factory specified undersize grinding, and so far I haven't found anything that they didn't do right, so I don't see why they would be wrong here).   For example, the Atomic Four engine main bearing journal standard size dimension specified in the service manual is 1.9880", +.0005" / -.000", which means each journal must not be worn oval or tapered more than .0005", as well as being the correct size so it will fit the bearing. If the journal is not oval or tapered more than .0005", but it is over 1.9885", then it is too big (not very likely unless the crank was built up with weld and not machined back to the correct size), and if the journal is under 1.9880" it is too small (probably from wear... but also not very likely that it wore perfectly round, since there is more pressure on the bearing and journal in some positions than in others). Usually the crank was originally the right size and has gradually worn oval, so one measurement will read around 1.9880" and the other measurement (in the position of highest pressure) will read around 1.986" or 1.987", meaning the crank is worn oval about 1 or 2 thousands of an inch (which is impossible to see with the naked eye). But it doesn't really matter whether it has worn large, small, tapered, or oval... if any of the micrometer readings of a standard sized main bearing journal are under 1.9880" or over 1.9885", then the crankshaft cannot be used without the main bearing journals first being machined to bring them within specifications (and new bearings of the correct size fitted). The same goes for rod bearing journals, except all measurements on them must not be under 1.5620" or over 1.5625" (for standard size journals).

All crank journals should be micro-polished to a mirror-like finish before the crankshaft is installed. You can do it yourself with strips of 600 grit wet/dry sandpaper the width of the journal dipped in parts cleaning fluid and spun around the journal with a boot lace.   Even if the crank journals are in good condition and within specification, a used crank that was found in a pile at the back of a shop some place and not taken from a running engine should be checked to make sure it is not bent and it doesn't have any cracks by an automotive machine shop before being installed (to make it perfect you can also have the machine shop balance it, but for that you also need to bring them the rods and pistons/piston pins/piston rings you are going to use) .

I removed my Atomic Four distributor to clean it, and although I marked the direction the rotor was pointing before I removed it, I forgot to mark the way the distributor itself was installed. Then, while the distributor was out my friend accidentally hit the starter button and turned the engine over. Now the spark plug wires don't fit properly and the engine pops in the carburetor and won't start... so I guess the distributor AND the rotor are in wrong. How do I reinstall the distributor and rotor correctly so the spark plug wires fit and it has the correct ignition timing so the engine will start?

The Atomic Four has a firing order of 1 2 4 3, and the crankshaft is designed so that pistons #1 and #4 go up and down together (and so do pistons #2 and #3, but 180 degrees out... when pistons #1 and #4 are at the top together, pistons #2 and #3 are at the bottom together). The reason to know this is that when piston #1 is at the top its firing stroke... firing #1 cylinder, piston # 4 is at the top of its exhaust stroke and just starting to do down on its intake stroke... with the exhaust valve just closing and the intake valve just opening, AND YOU CAN SEE PART OF THE INTAKE VALVE FOR #4 CYLINDER TO DETERMINE WHEN IT IS JUST STARTING TO OPEN BY LOOKING STRAIGHT DOWN #4 SPARK PLUG HOLE (IT'S THE ONLY VALVE YOU CAN SEE LOOKING STRAIGHT DOWN... WHEN IT IS FULLY DOWN IT IS CLOSED, SO WHEN IT STARTS TO OPEN IT WILL MOVE UP).

So, remove the spark plug for #4 cylinder (it's easier if you remove all the spark plugs) and turn the engine by hand in the direction of rotation (counterclockwise facing the flywheel) while looking straight down the #4 spark plug hole with a flashlight (if you can't look straight down the plug hole use a little piece of wood such as a popsicle stick to feel the valve going up and down). As the engine turns you will see the intake valve in #4 cylinder rising and falling. Carefully turn the engine over and stop just as you see the #4 intake valve just starting to move up (open). That will mean #1 cylinder is now at the firing position, so remove the distributor and install it so both the rotor and the wide protrusion in the side of the distributor points plate (which fits into a slot in the distributor cap to align it) both point at 9 o'clock (looking down on the top of the distributor facing the flywheel). Once the distributor is in leave the distributor clamp loose, and install the cap, spark plugs, and spark plug wires, making sure the plug wire for #1 cylinder goes in the 9 o'clock position, #2 plug wire goes in the 12 o'clock position, #4 plug wire goes in the 3 o'clock position, and #3 plug wire goes in the 6 o'clock position. Once the engine starts turn the distributor slightly back and forth so it runs the fastest. When everything is back in place time the engine at full speed as per the section on timing above.

I'm responsible for the maintenance of 2 charter sailboats, one with a Universal Atomic Four, and one with a Universal M25-XPB diesel. The owner's manual for the Atomic Four engine says the oil should be changed every 50 hours, and the owner's manual for the M25-XPB engine says the oil should be changed every 100 hours. How should I keep track of the engine hours, and does it make any difference if the hours are spent idling or at full cruise speed? Neither engine comes with an hour meter on the control panel, so I guess I need to install one on each boat, eh?

Hour meters are a very inefficient way to schedule an engine preventive maintenance (PM) program, because measuring the hours of use does not take into account the load on the engine while it was running, and engine load usually directly corresponds with engine wear... and engine wear is what is used to trigger a much more precise predictive maintenance (PdM) program.

A measurement that does correspond to engine load... and therefore engine wear, is energy consumption, which can be tracked easily by keeping a record of fuel purchases (some people use a specific credit card for boat fuel only, so they can get a regular report of fuel consumption on their credit card invoice).

Before fuel consumption can be used to schedule maintenance for a specific engine/boat combination the average fuel consumption per hour at full cruise speed needs to be calculated, usually by filling the fuel tank to the top, running the engine for exactly 1 hour under full cruise speed, and then measuring the amount of fuel needed to refill the tank to the top again.

For example, most direct drive Atomic Four engines burn an average of 4 litres (1 US gallon) per hour at cruise speed, so oil changes should be carried out when the Atomic Four gas receipts total approximately 200 litres (50 US gallons).

I'm installing an automatic bilge pump on my boat, and I plan to wire it directly from the battery so I can shut off the battery main switch and still have power to the automatic bilge pump when I leave the boat... besides, it's easier to wire that way. Another friend told me that although lots of people wire new appliances directly from the battery, he thinks that is the wrong way to connect anything. What is the correct way to wire an accessory that will be left on when the boat is not occupied, or any accessory for that matter?

Canadian Coast Guard regulations stipulate that before refueling, or in the event of an electrical fire, all electrical power should be shut off. Complying with that requirement can be very difficult to do quickly if some of the circuits bypass the battery main switch, ie are wired directly to the battery terminals... especially if the circuits are fitted with individual in-line switches and/or circuit breakers (which will normally be located in hard-to-find, out-of-the-way places).

To allow for quick and complete switching, as well as to ensure all circuits are protected with fuses or breakers, each circuit should originate from a fuse/breaker on the main 12 volt DC panel or an auxiliary 12 volt DC panel, all panels being fed from the battery main switch, so power on any circuit can be completely shut down quickly simply by turning the battery main switch to "OFF", or by turning off the specific switch/breaker for the circuit. Then... leaving the boat with only the automatic bilge pump activated is done by setting the battery main switch to the house battery, and then turning off all switches/breakers except the one that handles the automatic bilge pump.

Can I fit a new Universal diesel with a V drive gearbox in place of an Atomic Four with a V drive gear?

The latest (August 1991) "Universal Atomic Four Parts List" states on page 2:
"Repowering to Diesel...
- direct drive (5101) limited modifications
- reduction drive (5102) additional work - bedding
- V drive (5103) considerable work re-bedding due to V drive angle: Walters 22
degrees vs Hurth 15 degrees
There is no direct replacement diesel"

The Atomic Four installation manual specified an optimum engine installation angle of 7 degrees (because a V drive engine is mounted backwards that means 7 degrees sloping down towards the bow from horizontal). Most sailboat installations are around 7 degrees. Although the Parts List states the V angle is 22 degrees, the service manual and installation manual states the V angle is 24 degrees (for the Atomic Four and all other engines fitted with a Walter V drive). Assuming the engine is mounted at 7 degrees, the angle of the propeller shaft, AND THEREFORE THE ANGLE OF THE STERN TUBE GLASSED INTO THE HULL AS WELL AS THE PROP SHAFT BRACKET/CUTLASS BEARING will be 24 - 7 = 17 degrees from the horizontal... sloping down towards the stern. In order to fit a Universal diesel with a Hurth (ZF) V drive transmission (which are only available with a V angle of 15 degrees), so that the propeller shaft will follow the 17 degree angle of the stern tube, it must be mounted with an angle of -2 degrees (ie 2 degrees sloping up towards the bow).   The Universal diesel installation manual states that the maximum installation angle is 14 degrees, however it doesn't state a maximum negative angle... probably less than -5 degrees is OK (in order to ensure the oil in the pan doesn't sit in the front of the engine away from the oil pan/oil pump pickup tube), so a new diesel fitted with a V drive Hurth transmission can be fitted in place of a V drive Atomic Four without changing the angle of the stern tube and propeller shaft support strut/cutlass bearing if the angle of the stern tube glassed into the hull and the shaft support strut/cutlass bearing is between 1 degree and 20 degrees AND WHEN THE ENGINE IS INSTALLED THERE IS ROOM TO SWING THE LARGER DIAMETER PROPELLER USUALLY REQUIRED WHEN A DIESEL IS FITTED.

My friend says that when I rebuild my Atomic Four this winter I should get an automotive machine shop to "shave" the cylinder head, which will "hop up" the engine so I can get my sailboat to go faster when I run the engine. Should I do what he says?

No. "Shaving" the cylinder head refers to machining the cylinder head gasket surface, usually done on marine engines when the cylinder head is warped more than the OEM limit of .004", but often done on automobile engines for no other reason than to raise the compression ratio in an attempt to get more power. Increasing the compression ratio of an engine increases the power output, however the power increase is at the expense of increased heat and engine stress, including possible increased detonation/pre-ignition. The optimum compression ratio for the Atomic Four is 100 psi, so if "shaving" the head raises the compression higher than 100 psi it is not a good thing... it is a bad thing. Refer to Universal Service Bulletin 223 for more information.

My friend says that when I rebuild my Atomic Four I should get an automotive machine shop to do a "3 angle valve grind", but another friend says a "5 angle valve grind" is what I should get... not a "3 angle...". What the heck are they talking about?

The correct term is a "...valve SEAT grind". A valve job involves cutting (or grinding) the intake and exhaust valve faces, as well as the valve seats in the block (side valve engines like the Atomic Four) or cylinder head (overhead valve engines like all Universal diesels) to a smooth surface at the correct angle (the Universal Atomic Four has a valve and seat contact angle of 45° to the block deck). Because the valve seat is at the edge of an intake or exhaust port - usually the port is at approximately 90° to the block deck, and also the seat is surrounded by the combustion chamber - usually the chamber is at approximately 0° to the block deck, simply cutting the valve seat to 45° creates a valve seat with 3 angles... 0°, 45°, and 90°.

A proper valve job entails cutting the valve seats to the correct width (1/32" for Atomic Four engines) and ensuring the seat contacts the middle of the valve face. To size the valve seat and/or move the contact area on the valve face, cutters with angles of more than 45° and less than 45° respectively are used to remove metal from the outside and inside circumference of the valve seat... usually the cutters have angles of 30° and 60°. When these angles are combined with the other angles discussed above the valve seat has a total of 5 angles... 0°, 30°, °45°, 60°, and 90°. Although there are 5 angles involved, many machinists call a 5 angle valve seat grind a "3 angle grind" because they actually only use 3 stones or cutters..

Note:
Use machinist's blue or a felt marker pen to determine the position and width of the valve seat on the valve face. Valves and seats should never be "lapped" in using grinding paste after being cut with precision stones or cutters. The only reason to use grinding or lapping paste to "lap" valves is for an emergency repair when proper valve and seat cutting tools are not available. As well, when valve seats are lapped cold, the position of the valve on the seat changes slightly when the engine is fully warmed up, so the lapped areas no longer match.
Before cutting the valve seats, replace any valve guides worn beyond their wear limit... otherwise the cutter pilot will not be properly aligned with the seat, and once the engine is assembled the valves will not seal properly.

My friend says that when new Atomic Four engines were available from the Universal factory between 1948 and 1984 they could be ordered with several options. What was the complete list of options available, and are they still available today if an owner wishes to upgrade his/her existing engine?

The following accessories were available in 1976, and all are still available today.

Fresh water cooling (manufactured by Sendure)
6 unit control panel, electric - with tachometer & 3 metre harness cable
5 unit control panel, electric - no tachometer, & 3 metre harness cable
7 metre harness cable extension
55 amp Motorola alternator (substitute for standard 35 amp Motorola alternator)
rubber engine mounts (Bushings Unlimited DF100)
front PTO pulley kit (also supplied with fresh water cooling kit to drive seawater pump)
hand starting crank (cannot be used with front PTO pulley kit installed unless the pulley kit has a special adapter on the end for the hand starting crank)
spare parts kit

My boat developed a major leak and the Atomic Four engine was submerged half way up the flywheel housing.  The carburetor, fuel pump, and filter were all above water, but I pumped out 8 litres of sea water along with 3 litres  of engine oil, then filled the engine to the full mark on the dipstick with clean oil. What should I do now?  Is it sufficient to do several oil changes?  Should I be lubricating the pistons through the spark plug holes before start up?  Is there something else that must be done first?  Where would the water have entered?

The biggest danger is the salt water will cause the aluminum pistons to seize to the cast iron cylinder walls... you need to get the water displaced by oil as soon as possible to stop that happening. Some people immediately fill the engine right to the top with diesel fuel, kerosene, motor oil, or even fresh water by pouring it into the oil fill tube and through the spark plug holes until the engine is full... and then turning the engine over by hand to get it down the sides of the pistons... however if the accident just happened and the engine can still be turned a bit by hand (proving that it hasn't seized yet) you can just change the oil to remove most of the water in the crankcase and then try and start it.

1. Make sure the engine cooling water through-hull is closed so water doesn't get pumped to the engine when the engine is turned over.

2. Fill the engine with fresh oil and remove the spark plugs and turn the engine over with the starter.

3. If you don't get water spraying out of the spark plug holes put the plugs back in and try to start the engine.

4. If it starts turn on the engine cooling water through-hull and run it for a half hour, then change the oil and run it for a half hour and change the oil again. Run it under load tied to the dock so it gets hot enough to dry everything out, then spray the whole engine, mounts, etc with lots of penetrating oil. You may want to remove the starter and spray penetrating oil inside the nose on the bendix drive, etc.

5. If you get water spraying out of the spark plug holes remove the flame arrester and the pipe plug in the bottom of the carb float bowl and drain the carb. Activate the fuel pump hand lever until fresh gas pours out the bottom of the carb and then reinstall the plug. Keep cranking the engine until the water stops spraying out of the plug holes. Spray penetrating oil in the spark plug holes and carb and crank the engine over some more with the plugs out.

6. Remove the distributor cap and make sure it is dry inside... if it isn't blow the distributor points, cap, etc. dry and reinstall the cap.

7. Clean the plugs with a rag to make sure they're dry and put a spoonful of gasoline down each plug hole. Replace the plugs, make sure the choke is not on, and try to start the engine. If it starts do #4 above. If it won't start remove the plugs and dry them and try it again. Repeat until it starts (try it with the choke on to see if that helps) and then do #4 above.

Depending on the angle of the engine the lowest point water can enter the engine is through the air seal at the front of the crankshaft behind the flywheel, through the oil dipstick hole, through the valve cover breather hose at the carburetor flame arrester, at the oil fill vent cap, backwards from the exhaust system into the exhaust manifold and through the exhaust valve guides and piston rings, or up the intake manifold from the carburetor and past the intake valve guides and piston rings.

I want to replace the Universal Atomic Four gasoline engine in my C&C 34 with a Universal M-35B diesel. I have been told that the Universal M3-20B, M-25XPB, M-35B, and M-40B diesels are available with optional Atomic Four 11.5" mount spacing. Can I install the M-35B in my C&C without major modification to the stringers?

Nearly every boat will need some stringer and/or mount modification to fit a diesel in place of an Atomic Four, even if the stringers are the right distance apart, in order to get the engine at the right height to line up with the propeller shaft vertically. Although there are 4 models of Universal diesel available with 11.5" Atomic Four mount spacing this is irrelevant for most older C&C boats because most had standard 16" diesel stringer spacing anyway... even the boats that were fitted with Atomic Four engines, C&C used "L" shaped mounts when they installed an Atomic Four so it would fit the 16" stringers, and all new Universal diesels have 16" mounts. In most cases all that is necessary to install a diesel in an older C&C boat which was originally fitted with an Atomic Four is to raise the stringers 3/4" and then install the new diesel using the engine's 16" mounts.

When I run my Atomic Four engine hard for several hours I get smoky fumes in the cabin... should I fit a PCV valve kit?

Blue smoke in the exhaust is a sign of worn oil rings... oily blowby smoke in the cabin is a sign of worn or broken compression rings. Try checking the compression before and after pouring a small spoonful of oil down the spark
plug holes with the engine hot. If the reading comes up when the oil is added that is a sign the compression rings are worn, which is usually the case when there is smoke in the cabin.

Prematurely high blowby is sometimes caused by a severe overheating episode which glazed the cylinder bores and damaged the pistons and rings, however in most cases Atomic Four blow-by is caused by worn compression rings and piston ring lands from "ring wash", which occurs when the oil is washed away from the piston rings by liquid gasoline caused by the carburetor running excessively rich due to a too large main jet, an out-of-adjustment float level, a misadjusted choke cable which leaves the choke in a partially-on position when the choke knob is all the way in, or a dirty flame arrester. [Ring wash is not a temporary condition caused by excessive choke or the use of starting fluid during cold starting, it is a long-term condition caused by an overly rich fuel mixture.]

Make sure the carburetor has the #21 main jet (older carbs were fitted with a #24 jet, which was too rich), the timing is correct, and the engine is filled with the correct viscosity oil for the ambient temperature. You should also replace the oil filler cap, if it hasn't been replaced in several years, since the new ones have a foam element, rather than the chopped metal element used in the original caps, and the foam soaks up more of the oil droplets in the blow-by vapour than the chopped metal does (the oil filler cap breather is where most of the fumes exit the engine crankcase into the cabin).

You probably need a ring job (which really should be done in conjunction with a complete engine rebuild, since the engine has to be nearly totally disassembled anyway), however the PCV valve kit available from Indigo Electronics will help reduce the smoke in the cabin for a year or two until you get around to it. The Indigo kit uses an automotive PCV (positive crankcase ventilation) valve in place of the open breather hose, which sucks a lot more of the fumes into the intake manifold so it can be mixed with the gasoline/air mixture the engine runs on. Although it does reduce the blow-by vapour in the cabin, it increases the amount of oil in the exhaust, and subsequently more oil is expelled into the water... which is the reason we do not sell it.

You can buy one from the Indigo Electronics web site: www.atomic4.com . We suggest you read the section on oil consumption below before you order.

I know all engines burn some oil even when they're in good condition. What is normal oil consumption for an Atomic Four engine in good condition?

Engines burn more oil than normal when the piston oil rings are new and have not seated, or when the cylinder wall/pistons/piston rings are worn excessively or damaged. It usually takes 100 to 500 hours for oil rings to seat, however the process can be accelerated by using special "break-in oil" [we recommend John Deere break-in oil].

 Synthetic oil should not be used right after a rebuild, it is so effective a lubricant it can permanently prevent the rings from seating. Use synthetic oil in a new engine only after about 200 hours or the rings have seated and there is no evidence of  oil consumption/exhaust smoke/crankcase blow-by.

Some motorcycle and car race engine mechanics have a special procedure to seat rings quickly... they accelerate the vehicle from about 1/4 maximum rpm to 3/4 maximum rpm using short full throttle blasts in as high a gear as possible without lugging the engine. This puts a lot of pressure on the inside of the piston rings, which forces them out against the cylinder wall and encourages them to seat faster than normal.

Rings can take longer to seat, or may not seat at all if the cylinder walls were not honed, or were not honed properly to a crosshatch finish. The best way to hone cylinders to the correct cross-hatch finish while removing as much of the cylinder taper and out-of-round as possible is with an automotive machine shop "fixed" (rigid) cylinder hone, not with a flexible deglazing hone or a flexible ball hone.

After any honing operations the cylinders must be washed with hot water and soap and then wiped with clean rags dipped in clean oil... varsol and other solvents will not remove the microscopic pieces of hone abrasive, and if the abrasive bits are not removed before the engine is assembled the new rings will be scratched when the engine is started, causing excessive oil consumption and blow-by in the freshly rebuilt engine.

Some mechanics install pistons and piston rings "dry", no oil on the cylinder wall or piston or rings, to encourage a quick initial seating because the dry parts wear together for the first few seconds of initial engine startup. We do not recommend this practice because the parts may be damaged... not just seated, and it doesn't seem to work very well anyway... from our experience a break-in period is still required.

Volvo Penta and most other engine manufacturers specify maximum normal oil consumption as .75% of fuel consumption... which can also be stated as about 1 litre per 135 litres of fuel. Gasoline engines burn approximately .3 litre/hour per hp, so a Universal Atomic Four direct drive gasoline engine producing 15 hp @ 2,000 rpm would burn 4.5 litres/hour, or 225 litres per 50 hours of use - the recommended oil change interval, and therefore shouldn't use more than 1.7 litres of oil between oil changes. Diesel engines burn approximately .2 litre/hour per hp, so a Universal diesel engine producing 15 hp @ 2,000 rpm would burn 3 litres/hour, or 300 litres per 100 hours of use - the recommended oil change interval, and therefore shouldn't use more than 2.3 litres of oil between oil changes.

An interesting comparison can be made between the manufacturer's maximum oil consumption specification for four cycle inboard or outboard marine engines, and the oil/fuel mixture specification for the latest two cycle outboards, since two cycle outboards are close to the top of the environmental hit list precisely because they burn a mixture of oil and gasoline. The maximum four cycle oil consumption figure of .75% for an engine in good condition is very close to the 1% oil mix ratio specification (1% is a mix ratio of 1:100, or 1 litre per 100 litres of fuel) for the latest two cycle outboards. Because most two cycle outboard engines are smaller than most inboards, and therefore burn less fuel, an old four cycle inboard marine engine with worn oil rings is probably pumping more oil out the exhaust into the water than a modern two cycle outboard running on the recommended oil/gasoline fuel mixture.

The real fix for an engine which is burning oil is to rebuild it, however in order to keep old engines running a few more years many mechanics suggest using heavier oils, ie SAE 30 in northern climates or SAE 40 in the tropics, in order to reduce oil consumption by keeping the oil thicker even when the engine is hot. Oil additives such as STP, Motor Honey, etc work in a similar fashion by increasing the viscosity. One rather strange idea is the use of thick oil such as SAE 30 combined with a thin oil such as Marvel Mystery Oil... probably the viscosity when the two are combined is right back around 10-30, which is what the factory recommended in the first place, except who knows if Marvel Mystery Oil meets the API oil rating of good 10-30, or if the two oils combine without creating sludge which can damage the bearings and rings! [As far as I'm concerned the only "mystery" about Marvel Mystery Oil and other oil / fuel additives is why so many people waste their money on it!]

Marine engines with wet exhausts such as those used in many sailboats can hide oil consumption from worn piston rings because the oil gets absorbed into the water as it travels through the exhaust system... so it the oil consumption usually must be pretty high before the owner notices exhaust smoke. In the case of inboard gas engines like the Atomic Four, oil consumption from worn rings is usually accompanied by crankcase blowby vapours which smoke up the engine compartment. Just like oil consumption, the real fix for oily blowby vapours is an engine rebuild, however many Atomic Four owners get a few years before a rebuild by installing an Indigo Electronics PCV valve kit... which pulls the oily blowby vapours into the engine and burns them - presumably some return with blowby and are burned again and again, and some get blown out the exhaust into the water.

Many four cycle inboard marine engines with oil rings in good condition are guilty of pumping oil out the exhaust into the water needlessly because their owners are addicted to the long-term use of gasoline additives... some old-timers still like to add a bit of oil as a "top lubricant", which is was a light oil (sold in tiny little cans which looked like miniature oil cans) available 50 years ago and designed to be added to gasoline in order lubricate the valve guides, while others just want to become full members of the MMOUC ("Marvel Mystery Oil Users Cult") by adding it to the gas as well as the oil. [If you add outboard 2 cycle oil, Marvel Mystery Oil, or any other light oil to the fuel, run the engine for 1/2 an hour (the exhaust will show a smoky blue haze if you disconnect the exhaust pipe at the engine), and then remove the exhaust manifold you'll find that some of the oil has separated out of the gasoline and is pooling around the intake valve guides, and the rest has gone through the combustion chamber and left an oily residue in the exhaust ports and manifold, presumably the rest ends up in the water killing fish].

To make things worse the pollution caused by such additives is exacerbated because many users insist on doubling the quantities specified in the instructions on the can... the "if a pint is good, then a quart is better" philosophy.

The use of oil additives in conjunction with an Indigo Electronics PCV valve essentially makes a  boat with worn engine into a traveling oil spill, since it is pumping both burnt engine oil, burnt crankcase vapour oil, and burnt additive oil into the water behind the boat... at rates as high as about 1/4 litre per 8 hour day of use (a worn Atomic Four using 1.7 litres of oil per 50 litres of fuel and running at a speed of 5 kn with a .5 litre of fuel additive per 20 litre fill of fuel)... 1 litre of oil every 4 days. If I poured a litre of motor oil in the salmon river near my home every week I'd be arrested and jailed, but apparently it's OK to do the same thing by running it through an engine, since nobody seems to mind when when the oil is dumped into a fuel tank first!! 

In a more positive vein, a customer recently recommended Marvel Mystery Oil as the best "fogging oil" he's used [fogging oil is used before putting an engine in storage for the winter, or longer... a litre can is sprayed or poured into the engine carburetor or air intake at a rate which makes the engine exhaust smoke heavily without actually stopping the engine - coating the inside of the carburetor venturi/butterfly, intake manifold/intake valve stem, combustion chamber/piston crown, cylinder bore, exhaust manifold/exhaust valve stem, exhaust riser, and exhaust pipe with light oil, which prevents corrosion while the engine is not being used].

The mechanical fuel pump on my Atomic Four engine is old and leaking, so I want to buy a new one. I've noticed that my friend's Atomic Four has an electric pump, and she says it was original equipment. Should I buy a new mechanical pump, or a new electric pump?

The same AC Delco mechanical fuel pump was fitted to Atomic Four engines from 1948 to approximately 1978... after that Universal switched to a Facet electric pump. New AC Delco pumps are no longer available... new regulations prevented the sale of new ones for use on inboard gasoline marine engines because when the internal rubber diaphragm eventually ruptures after years of use gasoline is allowed to drip into the engine oil pan, and could cause an explosion (as well as diluting the engine oil and causing a crankshaft bearing failure). (Transport Canada Marine Safety Technical Publication TP 1332 - Construction Standards for Small Vessels specifies that fuel pumps fitted to inboard gasoline engines must not leak to the outside in the case of diaphragm failure). That is probably the reason Universal changed to an electric pump. The electric pump is sealed, as well as being a separate component from the engine, so an internal failure doesn't cause a gasoline leak. The electric pump has its own unique problems though... they require an oil pressure safety switch so the pump is automatically shut off when the engine stops for any reason or the key is left on, and they can be unreliable if the wiring gets old and corroded. Many people consider the mechanical pumps more reliable than the electric pumps, and so the mechanical pumps are often rebuilt and reinstalled when they fail.

A friend told me that small Kubota diesels have a very good reputation for long life and reliability, and suggested that I replace the Atomic Four engine in my boat with a new Beta marine engine because Betas are marinized Kubotas. Is that true?

Yes, Kubota Corporation of Japan has a very good reputation for building reliable, clean-running small industrial diesel engines... and yes, Beta marine engines are marinized Kubota engines. Most small marine engines are marinized versions of 3 well-known industrial engine brands... Kubota engines are the basis of Beta marine engines (England), Westward marine engines (Canada), Nanni marine engines (France), Phaser marine engines (USA - Florida), and the oldest and best known: Universal marine engines (USA - Massachusetts - subsidiary of Westerbeke Corporation). [All Universal diesel engines are Kubotas.] As well, Kubota industrial engine dealers in many countries can supply a custom-built marinized Kubota diesel on request.

Mitsubishi industrial engines are used to build Sole marine engines (Spain), some models of Vetus marine engines (Holland), some models of Westerbeke marine engines (USA - Massachusetts), and several other brands.

Yanmar Corporation uses their own industrial engines to manufacture the Yanmar line of marine engines.

When an Atomic Four was purchased new between 1948 and 1984 (when new engines were available from Universal) and a fresh-water-cooling system was specified at the time of order was the belt-driven sea water pump fitted a Sherwood R30G or a R30G-1, and what is the difference?

The Sherwood R30G has a flat shaft section designed to accept a pulley without a keyway, and the R30G-1 has a keyway cut in the shaft to accept a pulley with a keyway. Because cast iron Browning pulleys are no longer available with a keyway in the 1/2" ID size shaft of the R30G and R30G-1, the R30G is usually chosen as the replacement pump model, although the R30G-1 can also be used without a key by tightening the pulley set screw right down into the keyway cut into the shaft.

I tell everybody that the right oil for my 1971 Atomic Four is SAE 30 because that's what it says in my Operator's Manual. I read something on the internet which said the later manuals specify both SAE 10-30 and SAE 30. The latest Atomic Four Parts Manual has a specifications page which states the connecting rod nut torque is 33 lb ft, but a friend with an engine made in 1980 has an Owner's Manual which states the torque should be 25 lb ft. My engine rebuilder can't find the specification for connecting rod / pin clearance in the Parts Manual specifications page and wants to know what it is so he can finish the engine rebuild. Are there any other conflicting service specifications for the Atomic Four, and what are the correct specifications to use?

Later manuals often have revised or updated specifications for torque and lubricants, but even the latest Parts Manual available from the factory has some old specifications which were updated in newer owner's manuals. All manuals for the Atomic Four should be checked and updated if necessary to the following service specifications (see Technical Bulletins for an Atomic Four Engine Service specification change bulletin):

1. Revise:
Lubricating oil: SAE 30 or SAE 10-30 (old: SAE 30) [these days SAE 15-40, SAE 10-40, and SAE 20-50 is also used... we recommend the use of only SAE 10-40 or SAE 20-50 "SG equivalent" four-stroke motorcycle oil to help prevent clutch slip under full power - see Atomic Four Technical Bulletin #4]

2. Revise:
Connecting rod nut torque: 25 lb ft (old: 33 ft lb)

3. Revise:
Valve guide/valve stem clearance: intake & exhaust: .0025" - .0035" (old: .002" - .003", very old: intake .001" - .0015" / exhaust .0015 - .0025"). Some people suggest .003" - .004" is the best clearance spec to prevent valve stem sticking in raw-water-cooled engines running at temperatures under 140 F.

4. Revise:
Valve seat width: 1/32" (old: 1/16" - 5/64")

5. Misprint:
We believe the specification for Piston pin clearance in piston of .001" - .0002" which is in some books should read Piston pin clearance in piston: .0001" - .0002".

6. Add:
Piston pin clearance in connecting rod bushing: .0005" - .001"
[the clearance range specified by most engine rebuilders as well as the largest manufacturer of engine rebuilding equipment - Sunnen Products Company]

7. Revise:
Spark plug specification: Champion 592 / RJ12C (old: Champion J8J)

8. Revise:
Parts Manual Page 132 Section "Note: Starting 12-15-72 use the following after serial #178800..."
Retain existing text and add "15 - Clutch disc, inner - #285993 - change quantity to 2 instead of 3" under appropriate column headings.

My 1970 Atomic Four engine is raw water cooled (the boat is used in salt water) and is now overheating and blowing blue smoke from the exhaust. The mechanic says its overheating because the water jackets are plugged with salt, and its blowing blue smoke from the exhaust because the pistons and rings are worn out. He tested the oil pressure and says it is too low but he can't adjust it any higher because the crankshaft bearings are worn out. He says it needs a complete rebuild, but it's not worth rebuilding because the salt water has corroded the metal inside the block so that it is so thin it may crumble or crack after the block has been boiled in acid and machined ready for assembling. I know the engine is overheating and lots of blue smoke comes out the exhaust, but there is no sign of water in the oil. How does the mechanic know the engine is not worth rebuilding... maybe he's just trying to sell me a new diesel? 

Raw water cooled marine engines are designed to last about 10 - 15 years in salt water... and your engine is now 33 years old. The fact that your engine still runs OK and has no cracks or leaks is a testament to the thickness and quality of the high nickel content cast iron used by the Universal foundry, but after 33 years of hot salt water eating away the inside of the water jackets even the best quality cast iron will get so thin it will break through or crack unless it was flushed regularly with fresh water.

In order to evaluate the condition of the block your mechanic probably removed the manifold and manifold studs, and after checking for cracks counted the number of stud hole threads left in the block... counting the number of threads in the manifold stud holes is a measurement of the thickness of the metal left in that critical area around the ports (the weakest point of a raw water cooled Atomic Four). Deep cracks in the exhaust ports near the stud holes, or less than 4 threads in the stud holes means the block is too thin to be rebuilt. Another test, which involves the risk of destroying the block beyond repair, is to tap the block all over with a small ball peen hammer (except in the cylinder bores, deck surface, or other gasket surfaces) and see if the hammer breaks through the metal. 

Atomic Four manifold stud hole in block showing the number of threads left in the top of the hole: 2!!!... this block is not worth rebuilding.

My friend says modern diesels are better than old ones because they are designed differently and have "high torque rise" with a good "power bulge". What does that mean? Does the Atomic Four gasoline engine have "torque rise"? What is the difference between the Atomic Four and the Atomic Four Stevedore torque curves (a Stevedore is an Atomic Four with an intake manifold restrictor)? What is he talking about? Can a graph of the torque curve be used to determine the best cruising rpm?

He's referring to the power characteristics of many new model diesel engines compared to older designs, and the way the torque - rpm graph curves of the older and newer engines are different.

Torque is the twisting or turning force generated by the engine and delivered to the flywheel by the crankshaft. Torque is the value measured by a dynamometer in pounds-feet (lb-ft) or Newton-metres (Nm) [Pounds-feet is torque, foot-pounds is work]. Torque rise is the percentage of torque increase from the amount of torque produced at rated maximum rpm (which is usually also the maximum power rpm) to the greater amount of torque available as the engine rpm slows to torque peak rpm, with the engine at full throttle. Therefore torque rise is an indicator of an engine's ability to handle an additional load which causes the rpm to decrease from maximum power rpm.

                          Peak torque - Torque at Maximum Rated RPM
Torque Rise = ----------------------------------------------------------- x 100
                                  Torque at Maximum Rated RPM

The highest torque is produced at the rpm when the engine is burning the most fuel/air mixture and therefore producing the maximum force, or twist, on the crankshaft. Older engines have a "flat" torque curve, but newer engines are designed so torque is high throughout the recommended operating rpm range, but with an extra increase or "bulge" in the graph at about 75% of maximum rpm. That means that if the engine is running at an rpm greater than the torque peak rpm, when the boat gets a sudden additional load - a gust of wind or a higher than normal wave - as soon as the engine rpm starts to drop the torque automatically rises. On newer engines there is more of a rise in torque, and the extra torque rise helps to maintain a more constant boat speed in rough seas and when bucking gusting head winds.

Universal Engine Torque Rise Analysis

Atomic Four Torque Rise

torque at 3,500 rpm: 45.02 lb-ft
torque at 3,000 rpm: 43.77 lb-ft
torque rise: 0%

torque at 3,000 rpm: 43.77 lb-ft
torque at 2,500 rpm: 42.02 lb-ft
torque rise: 0%

torque at 2,500 rpm: 42.02 lb-ft
torque at 2,000 rpm: 42.54 lb-ft
torque rise: 1.24%
optimum continuous rpm which takes advantage of torque rise (direct drive engines): 2,125  rpm
optimum continuous rpm which takes advantage of torque rise (reduction drive engines): 2,500  rpm

Atomic Four Stevedore (with intake restrictor) Torque Rise

torque at 2,500 rpm: 37.81 lb-ft
torque at 2,000 rpm: 39.39 lb-ft
torque rise: 4.18%
optimum continuous rpm which takes advantage of torque rise (direct drive & reduction drive engines): 2,125  rpm
NOTE: The higher torque rise means the Atomic Four Stevedore is a better engine for use with a direct drive gear ratio in displacement hull boats (ie sailboats). Therefore... don't remove the intake restrictor from direct drive engines!

My friend says he heard that motorcycle oil should be used in Atomic Four engines. What is he talking about? 

Some modern "SJ" and "SL" rated automotive oils also marked "energy conserving" have extra friction reducing additives to help reduce fuel consumption. These additives may cause wet clutches like those used in motorcycles and Atomic Four Paragon gearboxes to slip under full power. Most 4 stroke motorcycle oils are rated "SG equivalent", because they don't have the extra additives of SJ / SL - energy conserving oils in order to ensure they won't cause clutch slip. SG rated oil is OK for Atomic Four engines, so your friend is right... if an Atomic Four forward clutch slips even after it's been adjusted as tight as possible, try switching to a 4 stroke motorcycle oil or a SG rated automotive oil (hard to find though, it's an old rating) and see if the clutch stops slipping.

For example, note the following excerpts from motorcycle oil technical literature:
Castrol Grand Prix 4 Stroke Motorcycle Oil: "...SG equivalent..."
Shell Advance SX4 Motorcycle Oil... "... protection for the wet clutch and gearbox"
Valvoline 4-Stroke Motorcycle Oil: "Protect Wet Clutch - optimal frictional characteristics for maximum power transfer..."
Belray EXL Motorcycle Motor Oil: "...for 4-stroke motorcycles..."
Pennzoil Motorcycle Motor Oil: "...gives excellent protection for transmissions and wet clutches..."
Quaker State 4-Cycle Motorcycle Engine Oil: "...non-friction modified for excellent performance in wet-clutch gear transmissions..."

The exhaust pipe on my 1949 Atomic Four broke and I need to replace it. It seems to be covered with a white tape like a bandage, and my friend says he heard that old engines sometimes had asbestos insulation on the exhaust, and that asbestos causes lung cancer. What should I do? 

Asbestos is hard to tell from old fibreglass tape, especially because it may be covered with a substance similar to plaster called "water glass", which is also used on fibreglass tape. When the engine was installed before 1970 and the exhaust insulation is breaking off in chunks like dry plaster assume it is asbestos... AND DO NOT CUT OR CHIP IT AND DO NOT BREATHE THE DUST - wear a good face mask rated for asbestos and carefully wrap the whole thing with a garbage bag or piece of plastic and seal the ends with duct tape, then remove or hacksaw the bolts or flange, and remove or cut the hose. Some people spray the whole thing lightly with water to ensure there is no dust, especially if they haven't got the right mask. Once the asbestos is sealed carefully remove the assembly from the boat and throw it in an industrial garbage disposal. It is very important not to get asbestos dust in the boat... if you do don't try to vacuum it up, the tiny asbestos fibres that cause lung cancer go right through vacuum filters (they are so small they cannot be seen with the naked eye) and will be dispersed throughout the air of the boat. If chunks fall off when you're installing the plastic wrap wet them and pick up what you can and then wash the dust into the bilge and pump the water out with the bilge pump.

Can a Briggs & Stratton industrial engine be used to replace an Atomic Four?

I've spent a lot of time trying to determine the best Atomic Four replacement engine for my customers. Air-cooled engines are noisy and give off a lot of heat - which makes the boat hot, and they're hard to cool when mounted in the engine compartment of a sail boat. Water-cooled 3 cylinder Briggs & Stratton Vanguard engines (made by Daihatsu) are available in gas, diesel, and propane. Propane is a possibility because a lot of sailboats have a propane tank for stove & heaters, but really the only viable engine type is a diesel...  getting rid of the gasoline engine is a major reason many people replace their Atomic Four (the major reasons to want a diesel are safety, offshore range, and the fact the boat increases in value/the boat is easier to sell). The Vanguard diesel looks like a nice little engine, but once you get finished marinizing it you won't save any money over just buying a standard production diesel marine engine, the diesel is more expensive than the gasoline version. Westerbeke still sells a 3 cylinder gasoline inboard (about a 70 hp) which can be used to replace an Atomic Four... but by far the best Atomic Four replacement for sailboats is a Universal M3-20B, M25-XPB, or M40B - depending on the size of the boat. If you compare what you get with those engines with any other (including the Spanish Sole - mother was right... you get what you pay for!), including a Kubota tractor engine marinized by a Kubota dealer, and take into account the brand recognition and reputation for quality of the Universal name, they can't be beat. Although the Universal is also a Kubota, it comes with a lot of good stuff not usually found on a marinized tractor engine... Atomic Four 11.5" & standard 16" mount spacing options, shallow marine oil pan (so the engine can be mounted closer to the rear of the boat, standard Universal cast iron marine exhaust manifold (Kubota shops usually weld one up when they marinize a tractor engine... try getting another one out of the parts book), standard oil change hose & pump, standard ZF Hurth gearbox with a choice of ratios, a selection of Universal exhaust risers/injection elbows that fit the Universal manifold, standard fail-safe marine engine mounts, top quality latest-model Sherwood 903 sea water pump, pre-wired to accept standard Universal plug-in control & alarm panels, decent parts/installation/service books, marine certified alternator (still required if the boat has propane, even if the gas engine is gone), marine electric fuel pump, engine mounted secondary fuel filter, etc, etc.

Why do some Atomic Four engines have trouble with sticking valves?

Atomic Four engines had some problems with valve sticking because the original clearance specification between the valve stem and the valve guide of .002" - .003"was a bit tight, and the exhaust valves would stick when carbon which had built up in the lower part of the valve guide jammed the valve stem in the valve guide when the guide and valve stem clearance became smaller when the engine was hot. In order to help correct his problem the factory made a modification to the valve clearance in 1970 (at serial # 176500), and increased the clearance specification to .0025" - .0035". This new specification is obtained when the valve guides are reamed to .315" - .316" (an 8 mm reamer is perfect). If non-standard bronze valve guides are installed they should have even more clearance... .004" - .005" because the bronze guides expand more than the standard cast iron guides. Even when valves are installed with the correct stem/guide clearance, exhaust valves sometimes stick when the valve springs become weak after the engine is seriously overheated. Valves also stick when the head gasket leaks and a bit of water gets into the space between the guide and the valve stem and rusts them together. In that case the fix is to remove the cylinder head and valve, and clean the guide with a wire guide brush and replace the head gasket. Valves also stick when enough carbon builds up in the valve guide and stem... and carbon can build up quickly if the engine is running cold (ie the thermostat has been removed), the engine is running rich (ie poorly tuned carburetor or dirty air filter/flame arrester element), fuel additives create deposits in the exhaust ports and valve guides, or the engine is burning oil (oil gets into the combustion chamber past worn piston rings and mixes with the carbon and builds up in the valve guide).

My engine suddenly overheated and it has lost engine coolant from the heat exchanger. What do I check to fix it?

The loss of engine coolant is probably caused by a leak, although if your catch tank was empty before then the engine may just have overheated without losing coolant. Fill the system with water (you don't need antifreeze until the engine is repaired) and pressure test with an automotive radiator tester (ie it pressurizes the system to force air/water out the leak). The usual cause of loss of coolant is a failed engine coolant pump (the engine coolant pump on diesel engines is driven by the alternator belt, and the pump has a hole in the bottom which is designed to drip water when the seal fails so it can be checked quickly to see if is leaking) or hose or a leaking heat exchanger (if you haven't replaced  the zinc in the heat exchanger regularly then the heat exchanger could have corroded inside and is leaking coolant into the sea water, and so you won't find an external leak on the engine.. you'll have to remove the heat exchanger and have it rebuilt at an automotive radiator shop

The main cause of overheating is a blocked sea water intake (ie plastic bag, jelly fish, sea weed, etc), a failed sea water pump (ie usually the impellor fails), a stuck engine coolant system thermostat, or a plugged sea water exhaust injection elbow (the exhaust injection elbow gets blocked from salt deposits building up at the point where they are injected into the exhaust (it is common to misjudge the amount of water coming out the exhaust because the exhaust splashes the water nearby and makes it looks like there is enough water flowing, when in fact there is little or none). Check those pieces one-by-one and make sure they are OK. You can remove the thermostat and run the engine without it if you want to see if that makes a difference. You can also heat the thermostat in a pot of water and watch to see if it opens fully before the water boils (no matter what temperature it is rated at it should open fully by 212 F).

My friend says that alternators have fans behind the pulley which draw air through the alternator from the back, and that the wrong fan can cause an alternator to burn out.  Is that true, because if it is why don't shops selling alternators ask what kind of fan my engine needs?

Your friend is right, alternators have a cooling fan which draws air into the alternator from the back and ejects it out the front around the belt pulley. Because an alternator will charge when it is rotated in either direction (clockwise or anticlockwise... facing the alternator pulley) and there is no standard rotation direction, many aftermarket alternators are fitted with bi-directional fans which can be used on any engine without changing the fan. Bi-directional fans are not as efficient as uni-directional fans designed to turn in one direction only, and in a hot sailboat engine compartment an alternator fitted with a bi-directional fan may run hot enough to burn out much sooner than expected, so most quality marine engine alternators are fitted with uni-directional alternator fans in order to keep the alternator as cool as possible.

My friend told me I should buy a "SpeedSeal" water pump cover for my diesel engine so I can change my water pump impellor quickly whenever it breaks. He says the knurled screws that hold the Speed Seal impellor cover on are designed to be loosened and tightened with the fingers and so the cover can be removed and replaced faster than by using a screwdriver to loosen and tighten the regular screws that hold the original water pump impellor cover on.

If the cooling system has a properly fitted sea water strainer and the sea water pump impellor is changed every 2 years like it should be then there will be no need for emergency impellor repairs... and therefore no need to deal with the real problem with a broken impellor, which is not installing a new one quickly without a screwdriver, but fishing out all the bits of broken impellor which have been pushed up  into the pump outlet fittings, hoses, heat exchanger (or in the case of raw-water-cooled engines engine water jackets, thermostat, block and manifold fittings), anti-siphon valve, and exhaust water injected elbow... causing endless overheating problems by intermittently partially blocking the flow of water even after the new impellor is installed until all the bits eventually work their way through the system or are all retrieved by methodically cleaning each component. The SpeedSeal encourages extended periods between impellor changes on the grounds that a broken impellor can be changed quickly, which is a BAD idea.

II have an Atomic Four engine in my sailboat, and my friend has a Universal diesel in his. He says all sailboat engines are fitted with transmissions that can be left in neutral when sailing, so the prop can freewheel and reduce the drag it would create if it wasn't able to turn. But another friend told me to leave my Atomic Four in reverse when I'm sailing... he says that's what he does when sailing his boat, which is fitted with a Universal M3-20 diesel. What's the right way?

There is no free-wheeling position on the Atomic Four transmission. In neutral the forward clutch plates are still rubbing slightly, and because there is no detent in reverse the transmission on a Universal Atomic Four should be in forward when sailing to make sure it doesn't turn and cause clutch plate wear.

There is some confusion about this procedure because the transmission on a Universal diesel is the opposite to the Atomic Four... depending on whether the boat is fitted with a fixed or folding/feathering propeller the transmission should be in reverse or neutral respectively when sailing. Leaving the transmission on a Universal diesel in forward while sailing will burn out the transmission.

In order to optimize sailing speed by reducing prop drag, before a fixed propeller fitted to a boat with an Atomic Four engine is locked by placing the transmission in forward the shaft should first be turned by hand in neutral until a mark on the shaft made when the boat was out of the water indicates that one of the propeller blades is "parked" directly in front of the shaft strut or keel.

My friend told me dielectric grease is used in electrical system connection plugs and spark plug wire connections to improve electrical conductivity. Someone else told me dielectric means it doesn't conduct electricity. What is dielectric grease for?

Dielectric grease doesn't conduct electricity at all. That allows it to be used in multiple-pin electrical connection plugs to seal the pins against corrosion from moisture (ie salt water & moisture laden sea air) while still allowing the plug to be disconnected easily, and without causing any "cross-connections" between other pins in the plug. It is also used in spark plug and distributor terminal caps to seal the spark plug wire terminals against moisture while not creating a path or "track" for the high-voltage carried by the spark plug wires to leak away to the engine block or other wires, which would cause the spark plugs to misfire.

Why do Atomic Four pistons have the "Front" arrow pointing to the back of the engine?

The Atomic Four engine manual states that #1 cylinder is the cylinder closest to the flywheel, however when the engine is apart it's quickly obvious to a mechanic that the engine must have been originally designed under the assumption that #4 cylinder (the cylinder closest to the transmission) was originally supposed to be designated #1. When #4 is firing the camshaft/crankshaft timing marks line up... and the cylinder at TDC (top dead centre) and firing when the timing marks are aligned is the normal way engine manufacturers designate #1 cylinder. So, it is likely that the Atomic Four pistons are marked with the "Front" text and arrow pointing to #4 cylinder, because somewhere in the distant past #4 cylinder was actually #1.

Are there any metric threads on the Atomic Four engine?

There are metric threads used on all Atomic Four engines, even the very first ones built in 1948... all the spark plugs have 14 mm metric threads.

Why are there holes in the Atomic Four camshaft?

The Atomic Four camshaft has a hole in the end and the side to allow any oil which has passed through the front crankshaft seal to drain back into the engine... the camshaft is cross-drilled from one side to allow the oil in the centre passage to be ejected from the camshaft back into the oil pan.

What earlier Universal engines were the basis for the Atomic Four?

The Atomic Four is very similar to the earlier Utility Four, however it has much more modern valve gear.

What company manufactured the original Atomic Four bronze gear water pump?

The bronze gear water pump fitted to the first Atomic Four engines was made by Universal.

What type of seal is used on the front of the Atomic Four crankshaft... and what is the part number?

There is no front seal... the design of the flywheel cover casting includes an "air seal" which separates the oil from the air passing around the crankshaft into the flywheel housing and drains it back into the engine through the camshaft. 

Atomic Four engines fitted with V drives have a breather cap on the marine gear cover plate as well as in the standard position in the front of the engine over the flywheel housing. Why?

On post-1968 Atomic Four engines the crankcase breather cap at the front of the engine over the flywheel housing is also used as an oil fill cap. When the engine is turned around and fitted with a V drive it is hard to access the oil fill cap, so Universal fitted another one on the marine gear cover because with the engine turned around the marine gear is at the front and easy to access. [this filler cap - the one on the marine gear cover - often spues oil thrown up by the spinning transmission shaft and clutch assembly... it should have been a sealed cap, not another breather]. Early model Atomic Four engines made before 1968 had "flip-up" hinged oil fill door located in the marine gear housing near the distributor which is actually easier to get at with the engine turned around and so an extra oil fill cap is not required on early engines when a V drive is fitted.

How is neutral adjusted in the Atomic Four transmission?

Neutral and reverse are adjusted by adjusting the reverse band adjusting nut so that with the gearshift lever in neutral the output shaft can be turned by hand, but has a slight drag from the reverse band touching the reverse drum. The "width" of the neutral position is dependent on how tight reverse is adjusted... a loose reverse adjustment = a wide neutral position, and vice versa.

What is "break-in", and when is it over?

Break-in is the initial period of running time for a new or rebuilt engine when the rings and bearings are "wearing in" so they make a good fit, and in the case of the rings - so they seal properly against the cylinder walls. In order to allow a "tight" engine to break-in properly (ie without any metal-to-metal contact at tight spots which could cause permanent damage) it is usually not fully loaded for long periods and kept at medium temperature. Until the rings are sealing properly against the cylinder walls the engine will tend to burn a bit more oil than it will when fully broken in... therefore break-in is over when the rings are sealing properly against the cylinder walls and oil consumption has dropped to its lowest point and is remaining stable. A normal break-in period for a new or rebuilt Universal or Westerbeke engine is usually around 100 hours. Do not use synthetic oil or oil additives during the break-in period. 

What is the most common problem with Atomic Four engines besides lack of regular maintenance and problems caused by the age of the engine?

Not being able to tell whether the engine quit due to a fuel problem, an electrical problem, or something else in order to repair the problem quickly and efficiently.

When an Atomic Four engine quits running without warning it can be very upsetting for the operator... suddenly they are faced with an unexpected problem that is always inconvenient, frequently embarrassing, and sometimes dangerous. Often they will report that after the engine stopped they let it sit for a while and then it started and ran, but they won't have any other information to help a mechanic diagnose the problem. What they need to do before the engine cools down (after making sure the boat isn't in any danger... possibly deploying the anchor or heaving to) is to immediately check the two main initial symptom branches at the top of the failure analysis hierarchy: whether the engine has one of two main symptoms... a dry carburetor float bowl (it's run out of fuel) or no electrical spark at the spark plugs (ignition failure).

Often when the engine quits suddenly the operator will assume that the engine has not run out of fuel because he/she has the incorrect notion (popular on the internet) that when an Atomic Four engine runs out of fuel it will miss and stumble a bit before stopping (no... usually they just suddenly quit dead!). The only real way to verify a gasoline engine has run out of fuel is to open the drain plug on the bottom of the carburetor and drain the fuel from the float chamber to physically verify the float chamber is (or is not) full of fuel (unless it has an automotive-style accelerator pump which can be seen squirting fuel when looking into the carb throat and moving the throttle... which most marine engines don't). Even then the problem can still be fuel-related, perhaps an internal carburetor problem such as water/dirt blocking a main jet. In most cases it is easier to make the first check removing a spark plug cap and holding the terminal 1/4" from the cylinder head while the engine is cranked to verify that a nice strong, blue, spark is being delivered to the plug by the coil/distributor (I just hold the terminal with my bare hand to see if I get a good shock) - if there is a spark then the assumption is made that the problem is something else... probably fuel, but the carb float bowl must be checked to see if it is empty before assuming anything, there are lots of other reasons why an engine can suddenly quit.

Usually when the engine quits after running for a long time on hot summer days and the symptom is ignition failure... the component that failed is the ignition coil (less commonly the condenser, the ignition switch, or the wiring harness connections).

Electric fuel pumps also fail when they get hot, however even though they are electrical components the symptom will be running out of fuel.

A defective electric fuel pump oil pressure safety switch or blown electric fuel pump fuse can be especially tricky to diagnose, because even when one or both have failed the engine will start up right away when the starter motor is engaged. The Atomic Four fitted with an electric fuel pump has separate fuse and starter motor solenoid "R" terminal safety switch bypass circuits... the fuel pump will be activated when the engine is cranked during starting, then once the engine starts the fuel pump will stop if the fuse or safety switch has failed - and the motor will quit about 5 minutes later (depending on the throttle setting... it will last a lot longer idling in neutral) when the carburetor float bowl is drained dry - again, the symptom is running out of fuel, but the problem is electrical.

Hot days can also cause engine failure due to fuel vapour lock in electric fuel pump hoses... in that case the symptom is running out of fuel (most vapour lock problems are caused by incorrect installation of the fuel lines and pump).

Often coil, condenser, ignition switch, wiring harness, fuel pump, safety switch, and vapour lock problems disappear mysteriously when the weather cools (ie it rains, or the sun goes down) and don't reappear until the next fast trip on a hot day. Identifying the symptom as either: 1. running out of fuel or 2. ignition failure or 3. something else, is the first important step in diagnosing the problem successfully.

Can an Atomic Four engine be checked using an automotive scope... what is the optimum primary pattern for both the original points/condenser ignition and a Pertronix electronic ignition?

Yes, Atomic Four engines are fitted with a standard 12 volt ignition system, except for some early models with 6 volt ignition systems and some other early models with optional magneto ignition (the later models were fitted with a Delco ignition that is the same one used on 4 cylinder GM / Chevrolet automobile engines) and so they can be checked using an automotive scope. The aftermarket Atomic Four Pertronix electronic ignition uses a magnetic trigger to replace the points and condenser, however it uses the same rotor, cap, and coil so it can also be checked using an automotive scope.

Atomic Four Engine Service Snap-on Tools automotive scope displaying an Atomic Four primary pattern (points/condenser)

The new spark plug recommendation for the Atomic Four engine is the Champion #592 - spec RJ12C. What does the Champion id number code mean?

RJ12C:
"R": fitted with a resistor to cut radio static
"J": 14 mm thread, 3/8" thread length
"12": heat range rating (slightly hotter than the original Atomic Four plug, the RJ8C)
"C": Champion "copper plus" design

Champion also list the #14 - spec RJ12YC. What does the extra "Y" mean?

"RJ12YC"
"Y": projected core nose

According to the Champion catalogue the RJ12YC is colder than the RJ12C, however since it has the same heat range id (12) AND a projected nose, it could mean it's colder, but the deposits burn off the projected nose and so the nominal heat range stays at 12. The projected nose on this plug "may" be hit with the intake valve if it is used in an Atomic Four... we haven't tried it, and can't be certain. Since the RJ12C plugs work well, we don't see any reason to experiment with other plugs, especially if it may lead to possible engine damage.

Some marine engine shops advertise that they have a "Master Mechanic" on staff. What does that mean?

There is no such registered trade as "Master Mechanic" in Canada, and I have never heard of there being one in the US either, although it is possible it is used in some states. The term "Master Mechanic" was sometimes used before World War II in mines in northern Canada to designate a heavy duty mechanic who also was trained as an electrician. It is sometimes used these days by sales staff to imply that an older mechanic is very experienced... often because he / she actually has no formal training or certification and doesn't want to be called a journeyman mechanic, since journeyman implies formal training and certification. The next time someone tells you they're a "master mechanic", ask to see the certification papers and license which uses the words “master” and proves they're one!

The alternator V belt on my Atomic Four is marked 11A 0635 / 15 250. The sea water pump V belt is marked FHP 4L 310. What do the belt markings mean?

There are basically 4 kinds of V belt classifications... Automotive - Imperial, Automotive - Metric, Industrial, and Fractional Horsepower.

Most alternator V belts fitted in motor vehicles are designated "automotive" belts and have a side angle of 36 degrees... and are marked with both the Automotive - Imperial size and the Automotive - Metric size. The standard Atomic Four alternator belt is marked with both the metric size: 11A 0635 and the Imperial (inch) size: 15 250. The metric size includes the width designator 11A (3/8") and the length 63.5 cm (25.4 inches). The Imperial size gives the width designator 15 (3/8") and the length 25 inches. Automotive belts are designed to be used with automotive pulleys with the same side angle.

Most aftermarket marine water pump V belts and compressors which use industrial-type pulleys (sheaves) designated "industrial" or "fractional horsepower" have a side angle of 36 degrees (now,  but belt angles are used to vary widely - see below) and are marked with either/both the Industrial and Fractional Horsepower size. Many standard Atomic Four sea water pump V belts are marked with the Fractional Horsepower size: 4L 310, and the Industrial size A 31. The Fractional Horsepower size includes the width designator 4L (1/2") and the length 31.0 inches. The Industrial size gives the width designator A (1/2") and the length 31 inches.

V belt side angles are not always consistent... especially with FHP and Industrial belts. When installing new pulleys always check to see if the belt fits the sheave properly, and then record the belt number so you can get the same replacement belt.

My Atomic Four Operator's Manual has an engine wiring diagram showing the ammeter + terminal connected to the battery + via the starter solenoid and battery cable... and all other engine panel circuits connected to the ammeter - terminal, including the alternator output terminal. My friend at the yacht club has an older model Atomic Four Operator's Manual which has an older wiring diagram showing the ammeter + terminal connected to the battery + via the starter solenoid and battery cable, and all other circuits except the alternator output terminal also originating at the ammeter terminal. The early Universal Diesel Operator's Manual shows the same wiring harness, but both terminals of the ammeter are labeled +. Why do the different schematics show the ammeter hooked up in different ways?

We're not sure why Universal didn't seem to be able to standardize the schematic showing ammeter wiring so it was the same for all of their engines. Basically there were 3 different wiring schematics for the ammeter... early gas engines (including the early Atomic Four), later new-style Atomic Four engines, and early Universal diesel engines (like automobile engines, most modern marine engines now have control panels fitted with voltmeters, not ammeters, so the issue of ammeter wiring doesn't apply to newer Westerbeke/Universal diesels).

The ammeter measures current flow, as well as flow direction, so that a "+" reading (the needle leans to the right to show a positive reading... the more it leans the more current is flowing) usually means the alternator is producing a current which is being fed to the battery and any other devices connected to the battery. When the ammeter needle leans left the reading is denoted as "-", because it usually means (depending on how the ammeter is wired) that the battery is not charging and its stored power is being used up providing electricity to the boat accessories.

Some ammeters have both terminals labeled "+", because in theory they are both in the positive circuit from the alternator to the battery, as well as the positive wires feeding the other circuits. Others have one terminal marked "+" and one terminal marked "-" in order to help identify which terminal to connect to so that the alternator reads properly.

Because the ammeter measures current flow and direction, you can hook it up so you get the reading you want... if you connect only the alternator output terminal to one of the ammeter terminals, and all other circuits to the other ammeter terminal, then the ammeter will read the total alternator output current for all circuits including battery charging. If you connect the alternator output, ignition switch, bilge blower, etc to one ammeter terminal, and the battery "+" to the other ammeter terminal, then the ammeter will read only the battery discharge and charge current (this is the configuration which should be used when an oversized alternator is fitted while retaining the standard ammeter, ie a 90 amp alternator and a 60 amp ammeter in order to help prevent ammeter damage the first time the alternator puts out a charge current which exceeds the full scale reading of the ammeter).

Where is the intake restrictor on an Atomic Four Stevedore, and what does it look like?

The Stevedore variant of the Atomic Four in direct drive configuration had a restrictor in the intake port right above the carburetor. Although most people remove them hoping they'll get more horsepower.... it doesn't make much difference to a direct drive engine because they don't rev much over 2,200 anyway. The restrictor is better left in place because it creates a different torque curve than the Atomic Four without a restrictor, and this modified torque curve has a "torque bump" which creates torque rise at cruise rpm... and torque rise is useful on a direct drive engine, it acts somewhat like a governor to maintain engine rpm and power when punching into waves.

Atomic Four "Stevedore" intake manifold restrictor insert in intake runner

What is the difference between low maintenance batteries and regular ones?

This link answers that question and many others: www.uuhome.de/william.darden/carfaq14.htm#jump

What is the best hose to use for connecting the propeller shaft stern tube to the shaft packing?

Some suppliers sell special hose for this purpose. We use hard-wall (wire wound) A2 fuel fill hose, because we want to make sure the hose doesn't rot in an oily bilge. We also use 316 stainless steel "T" clamps instead of regular hose clamps.

Stern tube hose and propeller shaft flange installation. Note "T" clamps and stainless steel lockwire on flange set screws. 3M 5200 marine sealant/adhesive is used to seal both ends of  hose.

The surveyor I hired to survey my boat told me all the hoses connected to through-hull fittings must be "double-clamped".  I assume she means I have to install 2 hose clamps at each fitting instead of just one... is that what it means?

Yes, the surveyor wants 2 clamps side-by-side on all the fittings. This is an old "rule" that often cannot actually be carried out, depending on the type of hose fitting and clamps used.

In the old days hoses were connected to short lengths of smooth pipe that were made by cutting a short length of pipe with a hacksaw or pipe cutter and cutting threads in one end. As well, hose clamps were often narrow assemblies made from wire (usually not stainless steel) formed around a bolt and nut, not the wide "gear clamps" used now. Because the pipe was smooth and the hose clamp was weak the connection often leaked, it was often possible to pull the hose off the pipe simply by jerking on it, and if the clamp was not stainless steel it often corroded and dropped off quickly when the clamp rusted through. For all 3 reasons many manufacturers and government agencies specified "double clamping" the connection.

These days cast brass or bronze "hose barb" fittings with specially designed ridges to grip the hose are used instead of pieces of pipe, and most do not have (or need) a barb long enough to accept 2 gear clamps. When 2 gear clamps are installed on these fittings, the inner clamp will not only not be clamping the hose to the barb... it's actually only decoration to make the surveyor happy, but it if it's tightened to much it may actually act to pull the hose off the barb, or cut the hose and allow it leak - exactly the opposite of the rationale for "double clamping" in the first place.

Can I still buy a head gasket for a 1965 Atomic Four Engine?

Yes. All head gaskets are the same, no matter what year the engine is - 1948 to 1980. Locate your nearest Westerbeke/Universal dealer or distributor from the list at www.westerbeke.com and order gasket #200452. You can also order one from any auto parts dealer... the gasket is a Victor #3647G, which is the same gasket sold by Westerbeke/Universal but will probably be cheaper in price. You only need one gasket unless the cylinder head has been ground a couple of times, when you should use 2 to keep the compression low so you don't blow the head gasket again. For a 1965 engine, use 2 head gaskets. Don't use any gasket cement. Torque the head nuts cold with oil on the threads and on the base of the nut to 35 ft. lb. torque, starting in the centre of the head and working out to the sides. Torque to 10 ft. lb., then to 25 ft. lb., and finally to 35 ft. lb.

go to Main Menu page