Engine Design

Cylinder And Valve Location

Bore ... 137.2 mm (5.40 in.)

Stroke ... 152.4 mm (6.00 in.)

Number And Arrangement Of Cylinders ... 65° V-12

Firing Order (Injection Sequence) ... 1,4,9,8,5,2,11,10,3,6,7,12

Rotation of Crankshaft (when seen from flywheel end) ... counterclockwise

Rotation of Fuel Pump Camshaft (when seen from pump drive end) ... counterclockwise

NOTE: Front end of engine is opposite to flywheel end. Left side and right side of engine are as seen from flywheel end. No. 1 cylinder is the front cylinder on the left side. No. 2 cylinder is the front cylinder on the right side.

Fuel System

Fuel System Schematic
(1) Fuel inlet line for the injection pump housing. (2) Damper. (3) Adapter with orifice. (4) Injection pump housing. (5) Fuel return line. (6) Junction block. (7) Fuel tank. (8) Fuel supply line. (9) Primary fuel filter. (10) Fuel transfer pump. (11) Pressure relief valve. (12) Priming bypass valve. (13) Fuel priming pump. (14) Main fuel filters. (15) Fuel pressure gauge.

This engine has a pressure type fuel system. There is one injection pump and injection nozzle for each cylinder. The injection pumps are in pump housing (4) on top front of the engine. The injection nozzles are in the precombustion chambers or adapters (for engines with direct injection) under the valve covers.

Fuel transfer pump (10) pulls fuel from fuel tanks (7) through primary filter (9) and sends it through priming pump (13), main filters (14) and to the manifold of the injection pump housing. The fuel in the manifold of the injection pump housing goes to the injection pumps. The injection pumps are in time with the engine and send fuel to the injection valves under high pressure.

On the inlet fitting to the fuel manifold (18) there is a damper (2) to reduce shock loads caused by the injection pumps. Some of the fuel in the fuel manifold is constantly sent through a restriction orifice (3) to remove air from the system. This restriction keeps fuel pressure high and controls the amount of fuel that goes back to the fuel tank through return line (5).

Location Of Fuel System Components
(1) Fuel inlet line for the injection pump housing. (2) Damper. (3) Adapter with orifice. (4) Injection pump housing. (5) Fuel return line. (8) Fuel supply line. (10) Fuel transfer pump. (16) Nut for a fuel injection line at the injection pump. (17) Fuel outlet line from transfer pump and inlet line to main filters. (18) Fuel manifold across the injection pump housing. (19) Adapter through the valve cover base.

Fuel priming pump (13) is used to fill the system with fuel and to remove air from the low pressure side of the fuel system. (Fuel filter, fuel lines and components).

Location Of Fuel System Components
(1) Fuel inlet line to injection pump housing. (5) Fuel return line to tank. (6) Junction block. (8) Fuel supply line. (13) Fuel priming pump. (14) Main fuel filters. (17) Fuel outlet line from transfer pump and inlet line to main filters.

The fuel transfer pump has a bypass valve and a check valve. The bypass valve (lower side) controls the maximum pressure of the fuel. The extra fuel goes to the inlet of the pump. The check valve allows the fuel from the tank to go around the transfer pump gears when the priming pump is used.

Fuel Injection Pump

The rotation of the cam lobes on camshaft (12) cause lifters (9) and pump plungers (5) to move up and down. The stroke of each pump plunger is always the same. The force of springs (6) hold lifters (9) against the cam lobes of the camshaft.

The pump housing is a "V" shape (similar to the engine cylinder block), with six pumps on each side.

When the pump plunger is down, fuel from fuel manifold (1) goes through inlet passage (2) and fills the chamber above pump plunger (5). As the plunger moves up it closes the inlet passage.

The pressure of the fuel in the chamber above the plunger increases until it is high enough to cause check valve (3) to open. Fuel under high pressure flows out of the check valve, through the fuel line to the injection valve, until the inlet passage opens into pressure relief passage (4) in the plunger. The pressure in the chamber decreases and check valve (3) closes.

The longer inlet passage (2) is closed, the larger the amount of fuel which will be forced through check valve (3). The period for which the inlet passage is closed is controlled by pressure relief passage (4). The design of the passage makes it possible to change the inlet passage closed time by rotation of the plunger. When the governor moves fuel racks (8), they move gears (7) that are fastened to plungers (5). This causes a rotation of the plungers.

Cross Section Of The Fuel Injection Pump Housing (Pumps Illustrated For DI Engine)
(1) Fuel manifold. (2) Inlet passage. (3) Check valve. (4) Pressure relief passage. (5) Pump plunger. (6) Spring. (7) Gear. (8) Fuel rack (left). (9) Lifter. (10) Link. (11) Lever. (12) Camshaft.

The governor is connected to the left rack. The spring load on lever (11) removes the play between the racks and link (10). The fuel racks are connected by link (10). They move in opposite directions (when one rack moves in, the other rack moves out).

Fuel Injection Valves (Nozzles) (On Earlier Engines)

The fuel injection nozzles fit into direct injection adapters or precombustion chambers that are installed in the cylinder head.

Fuel, under high pressure from the injection pump, is sent through the fuel injection line to the injection valve in the nozzle. The injection valve will not open until the fuel in the injection lines reaches a very high pressure. The valve then opens quickly to release the fuel directly into the engine cylinder on the DI engine. On the PC engine, the fuel is released into the precombustion chamber.

Fuel Injection Nozzles (On Later Engines)

The fuel injection nozzle is installed in an adapter in the cylinder head and is extended into the combustion chamber. The fuel injection pump sends fuel with high pressure to the fuel injection nozzle where the fuel is made into a fine spray for good combustion.

Fuel Injection Nozzle
(1) Carbon dam. (2) Seal. (3) Passage. (4) Filter screen. (5) Inlet passage. (6) Orifice. (7) Valve. (8) Diameter. (9) Spring.

Seal (2) goes against the nozzle adapter and prevents leakage of compression from the cylinder. Carbon dam (1) keeps carbon out of the bore in the nozzle adapter.

Fuel with high pressure from the fuel injection pump goes into inlet passage (5). Fuel then goes through filter screen (4) and into passage (3) to the area below diameter (8) of valve (7). When the pressure of the fuel that pushes against diameter (8) becomes greater than the force of spring (9), valve (7) lifts up. This occurs when the fuel pressure goes above the Valve Opening Pressure of the fuel injection nozzle. When valve (7) lifts, the tip of the valve comes off of the nozzle seat and the fuel will go through the six small orifices (6) into the combustion chamber.

The injection of fuel continues until the pressure of fuel against diameter (8) becomes less than the force of spring (9). With less pressure against diameter (8), spring (9) pushes valve (7) against the nozzle seat and stops the flow of fuel to the combustion chamber.

The fuel injection nozzle cannot be disassembled and no adjustments can be made.

Hydra-Mechanical Governor

The throttle lever, or governor control, is connected to the control lever on the engine governor. The governor then controls the amount of fuel needed to keep the desired engine rpm at the throttle lever setting.

The governor has governor weights (5) driven by the engine through drive assembly (15). The governor has a governor spring (6), valve (9) and piston (11). The valve and piston are connected to one fuel rack through pin (17) and lever (18). The pressure oil for the governor comes from the governor oil pump, on top of the injection pump housing. The oil used is from the engine lubrication system. Pressure oil goes through passage (14) and around sleeve (13). The throttle lever, or governor control, controls only the compression of governor spring (6). Compression of the spring always pushes down to give more fuel to the engine. The centrifugal force of governor weights (5) always pulls to get a reduction of fuel to the engine. When these two forces are in balance, the engine runs at the desired rpm (governed rpm).

Governor valve (9) is shown in the position when the force of the governor weights and the force of the governor spring are in balance.

Hydra-Mechanical Governor For Standard Engines (Later)
(1) Collar. (2) Bolt. (3) Lever assembly. (4) Upper spring seat. (5) Weights. (6) Governor spring. (7) Lower spring seat. (8) Thrust bearing. (9) Valve. (10) Upper oil passage in piston. (11) Piston. (12) Lower oil passage in piston. (13) Sleeve. (14) Oil passage in cylinder. (15) Drive assembly. (16) Cylinder. (17) Pin. (18) Lever.

When the engine load increases, the engine rpm decreases and the rotation of governor weights (5) will get slower. (The governor weights will move toward each other). Governor spring (6) moves valve (9) down. This lets the oil flow from lower passage (12) around valve (9) and through upper passage (10) to fill the chamber behind piston (11). This pressure oil pushes piston (11) and pin (17) down to give more fuel to the engine. (The upper end of the valve stops the oil flow through the top of the piston, around the valve). Engine rpm goes up until the rotation of the governor weights is fast enough to be in balance with the force of the governor spring.

Hydra-Mechanical Governor For Standard Engines (Earlier)
(1) Collar. (2) Bolt. (3) Lever assembly. (4) Upper spring seat. (5) Weights. (6) Governor spring. (7) Lower spring seat. (8) Thrust bearing. (9) Valve. (10) Upper oil passage in piston. (11) Piston. (12) Lower oil passage in piston. (13) Sleeve. (14) Oil passage in cylinder. (15) Drive assembly. (16) Cylinder. (17) Pin. (18) Levers.

When there is a reduction in engine load, there will be an increase in engine rpm and the rotation of governor weights (5) will get faster. This will move valve (9) up. This stops oil flow from lower passage (12), and oil pressure above piston (11) goes out through the top, around valve (9). Now, the pressure between sleeve (13) and piston (11) pushes the piston and pin (17) up. This causes a reduction in the amount of fuel to the engine. Engine rpm goes down until the centrifugal force (rotation) of the governor weights is in balance with the force of the governor spring. When these two forces are in balance, the engine will run at the desired rpm (governed rpm).

When engine rpm is at LOW IDLE, a spring-loaded plunger in lever assembly (3) comes in contact with a shoulder on the adjustment screw for low idle. To stop the engine, pull back on the governor control. This will let the spring-loaded plunger move over the shoulder on the low idle adjusting screw and move the fuel rack to the fuel closed position. With no fuel to the engine cylinders, the engine will stop.

The governor oil pump supplies high pressure oil to valve (9) to increase governor power and response. Oil from the governor oil pump gives lubrication to the governor weight support (with gear), thrust bearing (8), and drive gear bearing. The other parts of the governor get lubrication from "splash-lubrication" (oil thrown by other parts). Oil from the governor runs down into the housing for the fuel injection pumps.

Hydra-Mechanical Governor (Low Speed Engine)
(15) Drive assembly. (19) Rings. (20) Gear assembly. (21) Dowels (two).

The earlier and later governors for standard engines illustrated operate the same. The earlier governors have two levers (18) and the later governors have a one piece lever (18). The shut-off solenoid and fuel ratio control have been moved from the injection pump housing to the governor housing on the later governors.

The operation of the governor for the Low Speed Engine is the same as the Standard Engine governor except for the governor drive. This governor uses a "damped" drive system to remove any quick movement (forward and backward) of gear assembly (20). This can be caused by torsional (twisting) vibration through the engine drive lines which are passed on (sometimes increased) by drive assembly (15).

The top end of drive assembly (15) is between two rings (19) that are spring loaded. This creates enough friction to damper out the small frequencies but allows movement when a real need is necessary. Since governor weights (5) will now sense only true load changes, the engine will not go into a "hunt condition" (increase and decrease engine speed constantly).

Dashpot Governor

Cross Section Of Dashpot Governor
(1) Top cover. (2) Oil reservoir. (3) Cover for idle adjustment screws. (4) Collar bolt. (5) Dashpot chamber. (6) Dashpot piston. (7) Spring for dashpot piston. (8) Governor control shaft. (9) Governor spring. (10) Lower spring seat.

Hydra-mechanical governors for electric sets and some special applications have a piston (6) and spring (7) around bolt (4), plus an oil reservoir (2) and two adjustment screws (13 and 14). These parts control the flow of oil into and out of chamber (5) above the piston (6), through internal oil passages. With correct oil flow into and out of chamber (5), the lower spring seat (10) moves with more precision and the governor gives a better control of the engine speed. These governors are called "dashpot" governors. Except for their "dashpot" (cushion) effect, they work the same as the standard hydra-mechanical governors.

Top View Of Dashpot Governor
(1) Top cover. (3) Cover for idle adjustment screws. (8) Governor control shaft. (11) Adjustment screw for high idle speed. (12) Adjustment screw for low idle speed. (13) Dashpot adjustment screw. (14) Adjustment screw for the oil reservoir.

The oil for the dashpot action comes from the engine lubrication system. Adjustment screw (14) for the oil reservoir, on top of the governor, controls the oil flow from the lubrication system into reservoir (2). Too much flow fills the governor with oil and decreases governor performance. Too little flow does not give enough oil and the governor will "hunt" (increase and decrease engine speed constantly), as air gets into chamber (5) and lets lower spring seat (10) move faster.

Dashpot adjustment screw (13) on the side of the governor housing causes a restriction to oil flow into and out of the dashpot chamber (5). Too much flow lets lower spring seat (10) move faster and the governor will "hunt." Too little flow causes a slow governor action.

Hydraulic Fuel Ratio Control

The hydraulic fuel ratio control automatically controls the amount of travel of the rack in the "fuel-on" direction, until the air pressure in the inlet manifold is high enough to give complete combustion. The fuel ratio control keeps engine performance high.

The hydraulic fuel ratio control has two valves (2 and 11). Engine oil pressure works against valve (11) to control the movement of the fuel rack. Air pressure from the inlet manifold works against diaphragm assembly (3) to move valve (2) to control oil pressure against valve (11).

Fuel Ratio Control (Engine Stopped)
(1) Inlet air chamber. (2) Valve. (3) Diaphragm assembly. (4) Oil drains. (5) Pressure oil chamber. (6) Large oil passages. (7) Oil inlet. (8) Small oil passages. (9) Oil outlet. (10) Fuel rack linkage. (11) Valve.

With the engine stopped, valve (11) is in the fully extended position. The movement of fuel rack linkage (10) is not limited by valve (11).

When the engine is started, oil flows through oil inlet (7) into pressure oil chamber (5). From chamber (5) the oil flows through large oil passages (6), inside valve (11), and out small oil passages (8) to oil outlet (9).

A hose assembly connects inlet air chamber (1) to the inlet air system. As the inlet air pressure increases, it causes diaphragm assembly (3) to move down. Valve (2), that is part of the diaphragm assembly, closes large and small oil passages (6 and 8). When these passages are closed, oil pressure increases in chamber (5). This increase in oil pressure moves valve (11) up. The control is now ready for operation.

Fuel Ratio Control (Ready For Operation)
(1) Inlet air chamber. (2) Valve. (5) Pressure oil chamber. (6) Large oil passages. (8) Small oil passages. (11) Valve.

When the governor control is moved to increase fuel to the engine, valve (11) limits the movement of fuel rack linkage (10) in the "Fuel On" direction. The oil in chamber (5) acts as a restriction to the movement of valve (11) until inlet air pressure increases.

As the inlet air pressure increases, valve (2) moves down and lets oil from chamber (5) drain through large oil passages (6) and out through oil drains (4). This lets valve (11) move down so fuel rack linkage (10) can move gradually to increase fuel to the engine. The control is designed not to let the fuel increase until the air pressure in the inlet manifold is high enough for complete combustion. It prevents large amounts of exhaust smoke caused by an air-fuel mixture with too much fuel.

The control movements take a very short time. No change in engine acceleration (rate at which speed increases) can be felt.

Fuel Ratio Control (Increase In Inlet Air Pressure)
(2) Valve. (4) Oil drains. (5) Pressure oil chamber. (10) Fuel rack linkage. (11) Valve.

Automatic Timing Advance Unit

The automatic timing advance unit is installed on the front of camshaft (6) for the fuel injection pump and is gear driven through the timing gears. Drive gear (5) for the fuel injection pump is connected to camshaft (6) through a system of weights (2), springs (3), slides (4) and flange (1). Each one of the two slides (4) is held on gear (5) by a pin. The two weights (2) can move in guides inside flange (1) and over slides (4), but the notch for the slide in each weight is at an angle with the guides for the weight in the flange. As centrifugal force (rotation) moves the weights away from the center, against springs (3), the guides in the flange and the slides on the gear make the flange turn a small amount in relation to the gear. Since the flange is connected to the camshaft for the fuel injection pump, the fuel injection timing is also changed.

There is no adjustment for the timing advance unit.

Automatic Timing Advance Unit (Typical Illustration)
(1) Flange. (2) Weight. (3) Springs. (4) Slide. (5) Drive gear. (6) Camshaft.

Air Inlet And Exhaust System

The air inlet and exhaust system components are: air cleaner, turbocharger, aftercooler (if so equipped), inlet manifold (passages inside the cylinder block), cylinder head, valves and valve system components, and exhaust manifold.

Air Inlet And Exhaust System
(1) Exhaust manifold. (2) Inlet manifold and aftercooler. (3) Engine cylinder. (4) Air inlet. (5) Turbocharger compressor wheel. (6) Turbocharger turbine wheel. (7) Exhaust outlet.

Clean inlet air from the air cleaner is pulled through air inlet (4) of the turbocharger by the turning of compressor wheel (5). The compressor wheel causes a compression of the air. The air then goes to the aftercooler (if so equipped), and then to inlet manifold (2) of the engine. When the intake valves open, the air goes into engine cylinder (3) and is mixed with the fuel for combustion. When the exhaust valves open, the exhaust gases go out of the engine cylinder and into exhaust manifold (1). From the exhaust manifold, the exhaust gases go through the blades of turbine wheel (6). This causes the turbine wheel and compressor wheel to turn. The exhaust gases then go out exhaust outlet (7) of the turbocharger.

Air Inlet And Exhaust System
(1) Exhaust manifold. (2) Aftercooler. (4) Air inlet. (7) Exhaust outlet. (8) Turbochargers. (9) Cylinder head.

Air Flow Schematic (Engines With Aftercooler)
(1) Exhaust manifold. (2) Aftercooler. (4) Air inlet. (7) Exhaust outlet. (8) Turbochargers.

Air Flow Schematic (Engines Without Aftercooler)
(1) Exhaust manifold. (4) Air inlet. (7) Exhaust outlet. (8) Turbochargers. (10) Air collector.

Aftercooler

Some engines have an aftercooler (3) installed above the inlet manifold.

Air Inlet System
(1) Air inlet to turbo. (2) Compressed air from turbocharger. (3) Aftercooler. (4) Elbow on front bonnet of oil cooler.

The aftercooler lowers the temperature of the inlet air that comes from the compressor outlet of the turbocharger to approximately 93°C (200°F). This cooler air then goes into the engine cylinders.

Coolant for the aftercooler comes from the front bonnet (4) on the oil cooler.

Turbocharger

On the industrial engines, two turbochargers are mounted on the rear of the engine. All of the exhaust gases from the left exhaust manifold goes through the left turbocharger and the right turbocharger uses the exhaust gases from the right exhaust manifold.

Turbochargers (Industrial Engine)
(1) Exhaust manifolds. (2) Oil drain lines. (3) Oil supply line (one on each side). (4) Air inlet. (7) Exhaust outlet. (20) Air outlet. (21) Turbochargers.

Turbocharger (Marine Engine)
(1) Exhaust manifolds (watercooled). (2) Oil drain line. (3) Oil supply line. (4) Air inlet. (7) Exhaust outlet. (22) Turbocharger (watercooled). (23) Water outlet lines. (24) Water inlet line (from rear oil cooler bonnet).

Watercooled turbocharger (22) is installed at the rear of the marine engine on a cross pipe between the two water-cooled exhaust manifolds. All the exhaust gases from the engine go through the turbocharger.

The exhaust goes through the blades of turbine wheel (6). This causes the turbine wheel and compressor wheel (5) to turn, which causes a compression of the inlet air.

When the load on the engine is increased, more fuel is put into the engine. This makes more exhaust gases and will cause the turbine and compressor wheels of the turbocharger to turn faster. As the turbocharger turns faster, it gives more inlet air and makes it possible for the engine to burn more fuel and will give the engine more power.

Turbocharger (Typical Example)
(4) Air inlet. (5) Compressor wheel. (6) Turbine wheel. (7) Exhaust outlet. (8) Compressor housing. (9) Thrust bearing. (10) Sleeve. (11) Lubrication inlet port. (12) Turbine housing. (13) Sleeve. (14) Sleeve. (15) Oil deflector. (16) Bearing. (17) Oil outlet port. (18) Bearing. (19) Exhaust inlet. (20) Air outlet.

Maximum rpm of the turbocharger is controlled by the rack setting, the high idle speed setting and the height above sea level at which the engine is operated.

Bearings (16 and 18) for the turbocharger use engine oil under pressure for lubrication. The oil comes in through the oil inlet port (11) and goes through passages in the center section for lubrication of the bearings. Oil from the turbocharger goes out through the oil outlet port (17) in the bottom of the center section and goes back to the engine lubrication system.

The fuel rack adjustment is done at the factory for a specific engine application. The governor housing and turbocharger are sealed to prevent changes in the adjustment of the rack and the high idle speed setting.

Valve System Components

The valve system components control the flow of inlet air and exhaust gases into and out of the cylinders during engine operation.

The crankshaft gear drives the camshaft gear. The camshaft gear must be timed to the crankshaft gear to get the correct relation between piston and valve movement.

The camshaft has two cams for each cylinder. One cam controls the exhaust valves, the other controls the intake valves.

As the camshaft turns, the lobes of camshaft (9) cause lifters (8) to go up and down. This movement makes push rods (3) move rocker arms (2). Movement of the rocker arms makes bridges (1 and 11) move up and down on dowels mounted in the cylinder head. The bridges let one rocker arm open and close two valves (intake or exhaust). There are two intake and two exhaust valves for each cylinder.

Rotocoils (4) cause the valves to turn while the engine is running. The rotation of the valves keeps the deposit of carbon on the valves to a minimum and gives the valves longer service life.

Valve springs (5) cause the valves to close when the lifters move down.

Valve System Components
(1) Intake bridge. (2) Intake rocker arm. (3) Push rod. (4) Rotocoil. (5) Valve spring. (6) Valve guide. (7) Intake valves. (8) Lifter. (9) Camshaft.

Valve System Components
(1) Intake bridge. (2) Intake rocker arm. (7) Intake valves. (10) Exhaust rocker arm. (11) Exhaust bridge. (12) Exhaust valves.

Lubrication System

System Oil Flow

Flow Of Oil (Engine Warm)
(1) To rocker arm shaft. (2) (Earlier engines) to flywheel housing; (Later engines) passage is plugged. (3) Plug (on rear left). (4) To fuel injection pump housing, governor and fuel ratio control. (5) Rocker arm shaft. (6) To valve lifters. (7) Camshaft bearings. (8) Piston cooling tubes. (9) To timing gear housing. (10) Bore for idler gear shaft. (11) Oil manifold in cylinder block. (12) Main bearings. (13) Oil supply line to turbocharger. (14) Oil supply line to manifold in cylinder block. (15) Bypass valve for oil filters. (16) Bypass valve for oil cooler. (17) Turbocharger. (18) Engine oil cooler. (19) Oil return line from turbocharger. (20) Oil filters. (21) Oil pan. (22) Oil pump.

(Industrial Engine)

(Marine Engine) Lubrication System Components
(11) Oil manifold in cylinder block. (13) Oil supply line to turbocharger. (15) Bypass valve for oil filters. (16) Bypass valve for oil cooler. (18) Engine oil cooler. (19) Oil return line from turbocharger. (20) Oil filters. (21) Oil pan. (23) Oil inlet to cooler. (24) Oil outlet from oil cooler (inlet to filters). (25) Tube for oil level gauge. (26) Marine gear oil cooler or engine oil cooler bypass.

With the engine warm (normal operation), oil comes from oil pan (21) through a suction bell to oil pump (22). The oil pump sends warm oil to oil cooler (18) and then to oil filters (20).

From the oil filters, oil is sent to the oil manifold in the cylinder block and to oil supply line (13) for the turbocharger. Oil from the turbocharger goes back through an oil return line to oil pan (21).

From oil manifold (11) in one side of the cylinder block, oil is sent to the oil manifold in the other side through drilled passages in the cylinder block that connect main bearings (12) and the camshaft bearings (7). Oil goes through drilled holes in the crankshaft to give lubrication to the connecting rod bearings. A small amount of oil is sent through orifices (8) near the main bearings to make the pistons cooler. Oil goes through grooves in the bores for the front and rear camshaft bearings and then into passages (6) that connect the valve lifter bores. These passages give oil under pressure for the lubrication of the valve lifters.

Oil is sent through passages (1), on front and rear, to rocker arm shafts (5) on both cylinder heads. Holes in the rocker arm shafts let the oil give lubrication to the valve system components in the cylinder head.

In earlier engines, oil was sent through passage (2) to flywheel housing to provide oil for attachment drives or air compressor. In later engines, passage (2) is plugged. Oil is sent through an external line from the side of the cylinder block to the flywheel housing or directly to the air compressor.

Idler gear (10) gets oil from a passage in the cylinder block and in the shaft for the idler gear installed on the front of the cylinder block.

The fuel injection pump and governor gets oil from passage (4) in the cylinder block. There is a small gear pump between the injection pump housing and the governor. This pump sends oil under pressure for the hydraulic operation of the hydra-mechanical governor. Oil for the fuel ratio control is taken from the top of the governor on later engines and from the top of the fuel injection pump housing on earlier engines.

The automatic timing advance unit gets oil from the injection pump housing, through the camshaft for the fuel injection pumps.

There is a bypass valve in the oil pump. This bypass valve controls the pressure of the oil from the oil pump. The oil pump can put more oil into the system than is needed. When there is more oil than needed, the oil pressure goes up and the bypass valve will open. This allows the oil that is not needed to go back to the inlet oil passage of the oil pump.

After the oil for lubrication has done its work, it goes back to the engine oil pan.

Flow Of Oil (Engine Cold)
(13) Oil supply line to turbocharger. (14) Oil supply line to engine. (15) Bypass valve for oil filters. (16) Bypass valve for oil cooler. (17) Turbocharger. (18) Engine oil cooler. (19) Oil return line from turbocharger. (20) Oil filters. (21) Oil pan. (22) Oil pump.

With the engine cold (starting conditions), bypass valves (15 and 16) give immediate lubrication to all components when cold oil with high viscosity causes a restriction to the oil flow through engine oil cooler (18) and oil filters (20). The oil pump then sends the cold oil through the bypass valves to oil manifold (11) in the cylinder block and to supply line (13) for the turbocharger. Oil from turbocharger (17) goes back through oil return line (19) to oil pan (21).

When the oil gets warm, the pressure difference in the bypass valves decreases and the bypass valves close. Now there is a normal oil flow through engine oil cooler (18) and oil filters (20).

The bypass valves will also open when there is a restriction in the oil cooler or oil filter. This action does not let an oil cooler or oil filter with a restriction prevent the lubrication of the engine.

Cooling System

This engine has a pressure type cooling system. A pressure type cooling system gives two advantages. The first advantage is that the cooling system can have safe operation at a temperature that is higher than the normal boiling (steam) point of water. The second advantage is that this type system prevents cavitation (the sudden making of low pressure bubbles in liquids by mechanical forces) in the water pump. With this type system, it is more difficult for an air or steam pocket to be made in the cooling system.

Radiator Cooled System

In normal operation (engine warm), water pump (10) sends coolant through engine oil cooler (7) and then into the cylinder block. Coolant moves through the cylinder block to both cylinder heads, and then goes to the housings for the temperature regulators (3). The temperature regulators are open and most of the coolant goes through the outlets (4) to radiator (5). The coolant is made cooler as it moves through the radiator. When the coolant gets to the bottom of the radiator, it goes to water pump inlet (11).

Cooling System Components (Industrial Engine Shown)
(1) Turbocharger. (2) Aftercooler. (3) Temperature regulator housing. (4) Outlet to radiator top. (6) Outlet bonnet of oil cooler. (7) Engine oil cooler. (8) Line to aftercooler. (9) Inlet bonnet of oil cooler. (10) Water pump. (11) Water pump inlet, from radiator bottom. (12) Radiator bypass lines.

Example Of Radiator Cooled System
(1) Turbochargers. (2) Aftercooler. (3) Temperature regulator housings. (4) Outlet from temperature regulator housing to radiator top (one on each side of the engine front). (5) Radiator. (6) Outlet bonnet of oil cooler. (7) Engine oil cooler. (8) Line to aftercooler. (9) Inlet bonnet of oil cooler. (10) Water pump. (11) Water pump inlet, from radiator bottom. (12) Radiator bypass lines.

NOTE: The water temperature regulator is an important part of the cooling system. It divides coolant flow between radiator (5) and radiator bypass lines (12) as necessary to maintain the correct temperature. If the water temperature regulator is not installed in the system, there is no mechanical control, and most of the coolant will take the path of least resistance through the bypass. This will cause the engine to overheat in hot weather. In cold weather, even the small amount of coolant that goes through the radiator is too much, and the engine will not get to normal operation temperatures.

When the engine is cold, the water temperature regulator is closed, and the coolant is stopped from going to the radiator. The coolant goes from the temperature regulator housings (3) back to the water pump (10) through radiator bypass lines (12).

On engines with an aftercooler, part of the coolant flows to the engine oil cooler and part of the coolant flows through line (8) to the aftercooler. From the aftercooler, the coolant flows through the block, through the heads and back to the regulators.

On engines without an aftercooler, line (8) becomes an oil cooler bypass line, and it will connect to outlet bonnet (6) of the oil cooler. Part of the coolant will flow through engine oil cooler (7), and part will flow through bypass line (8). From outlet bonnet (6) all the coolant will flow into the cylinder block and then to both cylinder heads.

On some engine applications, water-cooled manifolds and a water-cooled turbocharger is used. With these engines, coolant, taken from the rear oil cooler bonnet (6), flows to the bottom of the watercooled turbocharger. From the top of the turbocharger, part of the coolant flows through a line back to the water pump and part of the coolant flows through the manifolds back to the regulators.

Systems Without Radiators

Keel Cooled Systems

With this cooling system an expansion tank is used, but the coolant flow in the engine is the same as the radiator cooled system. The coolant flows through the engine and back to the expansion tank in a constant cycle. When the temperature becomes high enough to open the regulators, the coolant flow is directed out through connection (7) to the keel cooling system, then back to the expansion tank through connection (3). The engine coolant is cooled as it flows through the keel circuit (9) by the sea water flowing past the cooling pipes on the keel.

Cooling System Components (Marine Engine Without Aftercooler)
(1) Turbocharger. (3) Jacket water return connection (from either keel cooler or heat exchanger). (4) Vent lines. (5) Temperature regulator housings (both sides). (7) Jacket water outlet connection (to keel cooler or heat exchanger). (8) Water pump. (12) Marine gear oil cooler or engine oil cooler bypass line. (13) Engine oil cooler. (14) Water cooled manifolds. (15) Inlet line for water-cooled turbocharger. (16) Turbocharger water outlet line to watercooled manifolds. (17) Turbocharger water outlet line to expansion tank. (18) Expansion tank. (19) Water pump inlet line from expansion tank. (20) Connection for engines with aftercooler.

Example Of Keel Cooled System
(1) Water cooled turbocharger. (2) Aftercooler. (3) Inlet connection for engine water return (either side). (4) Vent lines. (5) Water temperature regulator (both sides). (6) Connection for auxiliary tank. (7) Outlet n connection for engine water. (8) Engine water pump. (9) Keel cooler. (10) Duplex filter. (11) Bypass filter. (12) Oil cooler bypass or marine gear cooler. (13) Engine oil cooler. (14) Water cooled exhaust manifold.

Heat Exchanger Cooled System

When the engine is cooled by the heat exchanger system, an extra (auxiliary) water pump (6) is used to constantly pump filtered water from another source (either sea water or storage water) through the heat exchanger. When the engine reaches a temperature high enough to open the regulators, the coolant flow is directed around heat exchanger core (10) and then back to the expansion tank. Tho cooled coolant in the expansion tank is then picked up by engine water pump (8) and directed back through the engine.

Example Of Heat Exchanger Cooled System
(1) Water cooled turbocharger. (2) Aftercooler. (3) Inlet connection for engine water return (either side). (4) Vent lines. (5) Temperature regulator (both sides). (6) Auxiliary water pump. (7) Outlet connection for engine water (either side). (8) Engine water pump. (9) Duplex filter. (10) Heat exchanger. (11) Oil cooler bypass or marine gear cooler. (12) Engine oil cooler. (13) Water cooled exhaust manifold.

Coolant Conditioner

Some conditions of operation have been found to cause pitting (small holes in the metal surface) from corrosion or cavitation erosion (wear caused by air bubbles in the coolant) on the outer surface of the cylinder liners and the inner surface of the cylinder block next to the liners. The addition of a corrosion inhibitor (a chemical that gives a reduction of pitting) can keep this type of damage to a minimum.

The "spin-on" coolant conditioner elements, similar to the fuel filter and oil filter elements, fasten to a base that is mounted on the engine or is remote mounted. Coolant flows through lines from the water pump to the base and back to the block. There is a constant flow of coolant through the element.

The element has a specific amount of inhibitor for acceptable cooling system protection. As coolant flows through the element, the corrosion inhibitor, which is a dry material, dissolves (goes into solution) and mixes to the correct concentration. Two basic types of elements are used for the cooling system, and they are called the "PRECHARGE" and the "MAINTENANCE" elements. Each type of element has a specific use and must be used correctly to get the necessary concentration for cooling system protection. The elements also contain a filter and should be left in the system so coolant flows through it after the conditioner material is dissolved.

The "PRECHARGE" element has more than the normal amount of inhibitor, and is used when a system is first filled with new coolant. This element has to add enough inhibitor to bring the complete cooling system up to the correct concentration.

The "MAINTENANCE" elements have a normal amount of inhibitor and are installed at the first change interval and provide enough inhibitor to keep the corrosion protection at an acceptable level. After the first change period, only "MAINTENANCE" elements are installed at specified intervals to give protection to the cooling system.

Basic Block

Cylinder Block, Liners And Heads

The cylinders in the left side of the block make an angle of 65° with the cylinders in the right side of the block. The main bearing caps are fastened to the block with two bolts per cap.

The cylinder liners can be removed for replacement. The top surface of the block is the seat for the cylinder liner flange. Engine coolant flows around the liners to keep them cool. Three O-ring seals around the bottom of the liner make a seal between the liner and the block. A filler band at the top of each liner forms a seal between the liner and the cylinder block.

The engine has a single, cast head on each side. Four vertical valves (two intake and two exhaust) controlled by a pushrod valve system, are used per each cylinder. The opening for the direct injection adapter or prechamber is located between the four valves. Series ports (passages) are used for both intake and exhaust valves.

A steel spacer plate is used between the cylinder head and block. A thin gasket is used between the plate and the block to seal water and oil. A thick gasket of metal and asbestos is used between the plate and the head to seal combustion gases, water and oil.

The size of the pushrod openings through the head permits the removal of the valve lifters with the head installed.

Valve guides without shoulders are pressed into the cylinder head.

Pistons, Rings And Connecting Rods

The aluminum pistons have three rings; two compression rings and one oil ring. All rings are located above the piston pin bore. The two compression rings are of the KEYSTONE type, which have a tapered shape. The seat for the rings is an iron band that is cast into the piston. The action of the rings in the piston groove, which is also tapered, helps prevent seizure of the rings caused by too much carbon deposits. The oil ring is a standard (conventional) type. Oil returns to the crankcase through holes in the oil ring groove.

The piston for the direct injection engine has a cardioid design (special shape) on the top surface to help combustion efficiency. The piston for the prechamber engine has a steel heat plug fastened to the top of the piston at the center. The piston pin is held in place by two snap rings that fit in grooves in the pin bore of the piston.

The later connecting rod has a taper on the pin bore end. This gives the rod and piston more strength in the areas with the most load.

Oil spray tubes, located on the cylinder block main webs, direct oil to cool and give lubrication to the piston components and cylinder walls.

Crankshaft

The crankshaft changes the combustion forces in the cylinder into usable rotating torque which powers the machine. There is a gear at the front of the crankshaft to drive the timing gears and the oil pump.

The crankshaft is supported by seven main bearings. Pressure oil is supplied to all bearing surfaces through drilled holes in the crankshaft.

On Earlier Engines, lip seals and wear sleeves are used at both ends of the crankshaft for easy replacement and a reduction of maintenance cost.

Later Engines use seals and wear sleeves at both ends of the crankshaft that are a special design. The seal for the front is different than the seal for the rear. Special Instruction Form No. SMHS8008 gives the procedure that must be used to install these seals.

Camshaft

The engine has a single camshaft that is driven at the front end. It is supported by seven bearings. As the camshaft turns, each cam (lobe) (through the action of valve systems components) moves either two exhaust valves or two intake valves for each cylinder. The camshaft gear must be timed to the crankshaft gear. The relation of the cams (lobes) to the camshaft gear cause the valves in each cylinder to open and close at the correct time.

Vibration Damper

The twisting of the crankshaft, due to the regular power impacts along its length, is called twisting (torsional) vibration. The fluid type vibration damper is installed on the front end of the crankshaft. It is used for reduction of torsional vibrations and stops the vibration from building up to amounts that cause damage.

Electrical System

The electrical system has three separate circuits; the charging circuit, the starting circuit and the low amperage circuit. Some of the electrical system components are used in more than one circuit. The battery (batteries), circuit breaker, ammeter, cables and wires from the battery are all common in each of the circuits.

The charging circuit is in operation when the engine is running. An alternator makes electricity for the charging circuit. A voltage regulator in the circuit controls the electrical output to keep the battery at full charge.

If the machine has a disconnect switch, the starting circuit can operate only after the disconnect switch is put in the ON position.

The starting circuit is in operation only when the start switch is activated.

On precombusion engines, the starting circuit has a glow plug for each cylinder of the diesel engine. Glow plugs are small heating units in the precombustion chambers. Glow plugs make ignition of the fuel easier when the engine is started in cold temperature.

The low amperage circuit and the charging circuit are both connected to the same side of the ammeter. The starting circuit connects to the opposite side of the ammeter.

Charging System Components

Alternator (Delco-Remy)

The alternator is driven by V-belts from the crankshaft pulley. This alternator is a three phase, self-rectifying charging unit, and the regulator is part of the alternator.

This alternator design has no need for slip rings or brushes, and the only part that has movement is the rotor assembly. All conductors that carry current are stationary. The conductors are: the field winding, stator windings, six rectifying diodes and the regulator circuit components.

The rotor assembly has many magnetic poles like fingers with air space between each opposite pole. The poles have residual magnetism (like permanent magnets) that produce a small amount of magnet-like lines of force (magnetic field) between the poles. As the rotor assembly begins to turn between the field winding and the stator windings, a small amount of alternating current (AC) is produced in the stator windings from the small magnetic lines of force made by the residual magnetism of the poles. This AC current is changed to direct current (DC) when it passes through the diodes of the rectifier bridge. Most of this current goes to charge the battery and to supply the low amperage circuit, and the remainder is sent on to the field windings. The DC current flow through the field windings (wires around an iron core) now increases the strength of the magnetic lines of force. These stronger lines of force now increase the amount of AC current produced in the stator windings. The increased speed of the rotor assembly also increases the current and voltage output of the alternator.

The voltage regulator is a solid state (transistor, stationary parts) electronic switch. It feels the voltage in the system and switches on and off many times a second to control the field current (DC current to the field windings) for the alternator to make the needed voltage output.

Delco-Remy Alternator
(1) Regulator. (2) Roller bearing. (3) Stator winding. (4) Ball bearing. (5) Rectifier bridge. (6) Field winding. (7) Rotor assembly. (8) Fan.

Alternator (Bosch)

The alternator is driven by V-belts from the crankshaft pulley. This alternator is a three phase, self-rectifying charging unit, and the regulator is part of the alternator.

Bosch Alternator
(1) Fan. (2) Stator winding. (3) Field winding. (4) Regulator. (5) Ball bearing. (6) Roller bearing. (7) Rotor. (8) Rectifier assembly.

This alternator design has no need for slip rings or brushes, and the only part that has movement is the rotor assembly. All conductors that carry current are stationary. The conductors are: the field winding, stator windings, six rectifying diodes, and the regulator circuit components.

The rotor assembly has many magnetic poles like fingers with air space between each opposite pole. The poles have residual magnetism (like permanent magnets) that produce a small amount of magnet-like lines of force (magnetic field) between the poles. As the rotor assembly begins to turn between the field winding and the stator windings, a small amount of alternating current (AC) is produced in the stator windings from the small magnetic lines of force made by the residual magnetism of the poles. This AC current is changed to direct current (DC) when it passes through the diodes of the rectifier bridge. Most of this current goes to charge the battery and to supply the low amperage circuit, and the remainder is sent to the field windings. The DC current flow through the field windings (wires around an iron core) now increases the strength of the magnetic lines of force. These stronger lines of force now increase the amount of AC current produced in the stator windings. The increased speed of the rotor assembly also increases the current and voltage output of the alternator.

The voltage regulator is a solid state (transistor, stationary parts) electronic switch. It feels the voltage in the system and switches on and off many times a second to control the field current (DC current to the field windings) for the alternator to make the needed voltage output.

Alternator (Prestolite)

The alternator is driven by two V-belts from the fan pulley. It is a 24 volt, 19 ampere unit with a regulator which has no moving parts (solid state) installed on the side opposite the pulley. The alternator is made up of a head assembly on the drive end, rotor assembly, stator assembly, rectifier and heat removal assemblies, brush and holder assembly, head assembly on the ring end and regulator.

The rotor assembly has the field windings (wires around an iron core) which make magnet like lines of force when direct current (DC) flows through them. As the rotor turns, the magnet like lines of force are broken by the stator. This makes an alternating current (AC) in the stator. The rectifier has diodes which change the alternating current (AC) from the stator to direct current (DC). Most of the direct current (DC) goes to charge the battery and make a supply of direct current (DC) for the low amperage circuit. The remainder of the direct current (DC) is sent to the field windings through the brushes.

Prestolite Alternator
(1) Brush assembly. (2) Stator. (3) Rotor. (4) Roller bearing. (5) Slip rings. (6) Ball bearing.

Alternator (Motorola)

The alternator is a three phase, self-rectifying charging unit that is driven by V-belts. The only part of the alternator that has movement is the rotor assembly. Rotor assembly (4) is held in position by a ball bearing at each end of the rotor shaft.

The alternator is made up of a front frame at the drive end, rotor assembly (4), stator assembly (3), rectifier assembly, brushes and holder assembly (5), slip rings (1) and rear end frame. Fan (2) provides heat removal by the movement of air through the alternator.

Rotor assembly (4) has field windings (wires around an iron core) that make magnetic lines of force when direct current (DC) flows through them. As the rotor assembly turns, the magnetic lines of force are broken by stator assembly (3). This makes alternating current (AC) in the stator. The rectifier assembly diodes that change the alternating current (AC) from the stator to direct current (DC). Most of the DC current goes to charge the battery and make a supply for the low amperage circuit. The remainder of the DC current is sent to the field windings through the brushes.

Motorola Alternator
(1) Slip rings. (2) Fan. (3) Stator assembly. (4) Rotor assembly. (5) Brush and holder assembly.

Alternator (Nippondenso)

The alternator is driven by V-belts from the crankshaft pulley. There is a 35 amp and a 50 amp, 24 volt alternator available. The alternators are brushless and contain an internally mounted, solid state voltage regulator.

Nippondenso Alternator Components
(1) Fan. (2) Front frame assembly. (3) Stator assembly. (4) Rotor assembly. (5) Field winding (coil) assembly. (6) Regulator assembly. (7) Condenser (suppression capacitor). (8) Rectifier assembly. (9) Rear frame assembly.

The major components of the alternator are stator assembly (3), rectifier assembly (8), field winding (5), rotor assembly (4), regulator assembly (6) and condenser (suppression capacitor) (7).

Stator assembly (3) consists of a stator core and coils. As the rotor turns, its varying magnetic field causes the stator coil to produce three-phase alternating current (AC).

Rectifier assembly (8) contains three positive diodes and three negative diodes to form the full wave rectifier which is connected to the stator assembly. The 50A alternator has four positive and four negative diodes. Rectifier assembly (8) changes three-phase AC to DC and provides excitation current through three exciter diodes.

Field winding (5) is a stationary coil assembly that provides the magnetic field for the rotor assembly. Rotor assembly (4) provides the north and south poles which cut the magnetic field between the rotor field winding and the stator assembly. The north and south poles are separated by non-magnetic ring (12).

Regulator assembly (6) controls alternator output. It is mounted inside the rear frame assembly.

Condenser (7) serves as a suppression capacitor. It protects the alternator diodes from voltage spikes. It also suppresses radio and electronic interference. Condenser (7) also contains a resistor which is in series with the condenser. The condenser is mounted in the rear frame assembly on top of the regulator assembly.

Alternator Regulator (Bosch)

The voltage regulator is an electronic switch. It feels the voltage in the system and gives the necessary field current (current to the field windings of the alternator) for the alternator to make the needed voltage. The voltage regulator controls the field current to the alternator by switching on and off many times a second.

Regulator (Bosch)

Alternator Regulator (Prestolite)

The voltage regulator is a solid state (transistor, no moving parts) electronic switch. It feels the voltage in the system and gives the necessary field current (current to the field windings of the alternator) for the alternator to make the needed voltage. The voltage regulator controls the field current to the alternator by switching on and off many times a second.

Regulator (Prestolite)

Alternator Regulator (Nippondenso)

The voltage regulator is a solid state (transistor, no moving parts) electronic switch. It feels the voltage in the system and gives the necessary field current (current to the field windings of the alternator) for the alternator to make the needed voltage. The voltage regulator controls the field current to the alternator by switching on and off many times a second. There is no voltage adjustment for this regulator.

Regulator (Nippondenso)

Alternator Regulator (Motorola)

The voltage regulator is not fastened to the alternator, but is mounted separately and is connected to the alternator with wires. The regulator is a solid state (transistor, stationary parts) electronic switch. It feels the voltage in the system and switches on and off many times a second to control the field current (DC current to the field windings) for the alternator to make the needed voltage output. There is a voltage adjustment for this regulator to change the alternator output.

Regulator (Motorola)

Starting System Components

Solenoid

A solenoid is a magnetic switch that does two basic operations:

a. Closes the high current starter motor circuit with a low current start switch circuit.

b. Engages the starter motor pinion with the ring gear.

Typical Solenoid Schematic

The solenoid switch is made of an electromagnet (one or two sets of windings) around a hollow cylinder. There is a plunger (core) with a spring load inside the cylinder that can move forward and backward. When the start switch is closed and electricity is sent through the windings, a magnetic field is made that pulls the plunger forward in the cylinder. This moves the shift lever (connected to the rear of the plunger) to engage the pinion drive gear with the ring gear. The front end of the plunger then makes contact across the battery and motor terminals of the solenoid, and the starter motor begins to turn the flywheel of the engine.

When the start switch is opened, current no longer flows through the windings. The spring now pushes the plunger back to the original position, and, at the same time, moves the pinion gear away from the flywheel.

When two sets of windings in the solenoid are used, they are called the hold-in winding and the pull-in winding. Both have the same number of turns around the cylinder, but the pull-in winding uses a larger diameter wire to produce a greater magnetic field. When the start switch is closed, part of the current flows from the battery through the hold-in windings, and the rest flows through the pull-in windings to motor terminal, then through the motor to ground. When the solenoid is fully activated (connection across battery and motor terminal is complete), current is shut off through the pull-in windings. Now only the smaller hold-in windings are in operation for the extended period of time it takes to start the engine. The solenoid will now take less current from the battery, and heat made by the solenoid will be kept at an acceptable level.

Starter Motor

The starter motor is used to turn the engine flywheel fast enough to get the engine to start running.

The starter motor has a solenoid. When the start switch is activated, the solenoid will move the starter pinion to engage it with the ring gear on the flywheel of the engine. The starter pinion will engage with the ring gear before the electric contacts in the solenoid close the circuit between the battery and the starter motor. When the circuit between the battery and the starter motor is complete, the pinion will turn the engine flywheel. A clutch gives protection for the starter motor so that the engine can not turn the starter motor too fast. When the start switch is released, the starter pinion will move away from the ring gear.

Starter Motor Cross Section
(1) Field. (2) Solenoid. (3) Clutch. (4) Pinion. (5) Commutator. (6) Brush assembly. (7) Armature.

Magnetic Switch

A magnetic switch (relay) is used sometimes for the starter solenoid or glow plug circuit. Its operation electrically, is the same as the solenoid. Its function is to reduce the low current load on the start switch and control low current to the starter solenoid or high current to the glow plugs.

Other Components

Circuit Breaker

Circuit Breaker Schematic
(1) Reset button. (2) Disc in open position. (3) Contacts. (4) Disc. (5) Battery circuit terminals.

The circuit breaker is a switch that opens the battery circuit if the current in the electrical system goes higher than the rating of the circuit breaker.

A heat activated metal disc with a contact point makes complete the electric current through the circuit breaker. If the current in the electrical system gets too high, it causes the metal disc to get hot. This heat causes a distortion of the metal disc which opens the contacts and breaks the circuit. A circuit breaker that is open can be reset (an adjustment to make the circuit complete again) after it becomes cool. Push the reset button to close the contacts and reset the circuit breaker.

Shutoff Solenoid

The rack shutoff solenoid, when activated, moves the shutoff lever in the governor housing which in turn moves the fuel rack to the fuel closed position. The solenoid is activated by a manual control switch.

Wiring Diagrams

Many types of electrical systems are available for these engines. Some charging systems use an alternator and a regulator in the wiring circuit. Others have the regulator inside the alternator. Some starting systems have one starting motor. Engines which must operate in bad starting conditions can have two starting motors. Other starting systems use air or hydraulic motors.

On prechamber (PC) engines, glow plugs are provide for low teperature starting conditions. PC engines without glow plugs are usually used where ideal starting conditions exist or where an Automatic Start-Stop system is used.

A fuel pressure switch is used in all systems with an external regulator. The switch prevents current discharge (field excitation) to alternator from the battery when the engine is not in operation. In systems where the regulator is part of the alternator, the transistor circuit prevents current discharge to the alternator and the fuel pressure switch is not required.

All wiring schematics are usable with 12, 24, 30 or 32 volts unless the title gives a specific description.

NOTE: Automatic Start-Stop systems use different wiring diagrams. Make reference to the ENGINE ATTACHMENTS section of this Service Manual.

The chart that follows gives the correct wire sizes and color codes.

Grounded Electrical Systems

(Regulator Separate From Alternator)

Charging System
(1) Ammeter. (2) Regulator. (3) Battery. (4) Pressure switch. (5) Alternator.

Charging System With Glow Plugs
(1) Heat-Start switch. (2) Ammeter. (3) Glow plugs. (4) Regulator. (5) Battery. (6) Pressure switch. (7) Alternator.

Charging System With Electric Starting Motor
(1) Start switch. (2) Ammeter. (3) Regulator. (4) Starting motor. (5) Battery. (6) Pressure Switch. (7) Alternator.

Charging System With Electric Starting Motor And Glow Plugs
(1) Heat-Start switch. (2) Ammeter. (3) Glow plugs. (4) Regulator. (5) Battery. (6) Starting motor. (7) Pressure switch. (8) Alternator.

Charging System With Two Electric Starting Motors
(1) Magnetic switch. (2) Start switch. (3) Ammeter. (4) Regulator. (5) Battery. (6) Starting motor. (7) Pressure switch. (8) Alternator.

Charging System With Two Electric Starting Motors And Glow Plugs
(1) Heat-Start switch. (2) Magnetic switch. (3) Glow plugs. (4) Ammeter. (5) Regulator. (6) Battery. (7) Starting Motor. (8) Pressure switch. (9) Alternator.

Insulated Electrical Systems (Regulator Separate From Alternator)

Charging System
(1) Ammeter. (2) Regulator. (3) Battery. (4) Pressure switch. (5) Alternator.

Charging System With Glow Plugs
(1) Heat-Start switch. (2) Magnetic switch. (3) Glow plugs. (4) Ammeter. (5) Regulator. (6) Battery. (7) Pressure switch. (8) Alternator.

Charging System With Electric Starting Motor
(1) Start switch. (2) Ammeter. (3) Regulator. (4) Starting motor. (5) Battery. (6) Pressure switch. (7) Alternator.

Charging System With Electric Starting Motor And Glow Plugs
(1) Magnetic switch. (2) Heat-Start switch. (3) Ammeter. (4) Glow plugs. (5) Regulator. (6) Battery. (7) Starting motor. (8) Pressure switch. (9) Alternator.

Charging System With Two Electric Starting Motors
(1) Magnetic switch. (2) Start switch. (3) Ammeter. (4) Regulator. (5) Battery. (6) Starting motor. (7) Pressure switch. (8) Alternator.

Charging System With Two Electric Starting Motors And Glow Plugs
(1) Heat-Start switch. (2) Magnetic switch. (3) Glow plugs. (4) Ammeter. (5) Regulator. (6) Battery. (7) Starting motor. (8) Pressure switch. (9) Alternator.

Grounded Electrical System (Regulator Inside Alternator)

Charging System
(1) Ammeter. (2) Alternator. (3) Battery.

Charging System With Glow Plugs
(1) Heat-Start switch. (2) Ammeter. (3) Glow plugs. (4) Battery. (5) Alternator.

Charging System With Electric Starting Motor
(1) Start switch. (2) Ammeter. (3) Alternator. (4) Battery. (5) Starting motor.

Charging System With Electric Starting Motor And Glow Plugs
(1) Heat-Start switch. (2) Ammeter. (3) Glow plugs. (4) Battery. (5) Starting motor. (6) Alternator.

Charging System With Two Electric Starting Motors
(1) Magnetic switch. (2) Start switch. (3) Ammeter. (4) Battery. (5) Starting motors. (6) Alternator.

Charging System With Two Electric Starting Motors And Glow Plugs
(1) Magnetic switch. (2) Heat-Start switch. (3) Ammeter. (4) Glow plugs. (5) Battery. (6) Starting motors. (7) Alternator.

Insulated Electrical System (Regulator Inside Alternator)

Charging System
(1) Ammeter. (2) Alternator. (3) Battery.

Charging System With Glow Plugs
(1) Heat-Start switch. (2) Magnetic switch. (3) Glow plugs. (4) Ammeter. (5) Battery. (6) Alternator.

Charging System With Electric Starting Motor
(1) Start switch. (2) Ammeter. (3) Alternator. (4) Battery. (5) Starting motor.

Charging System With Electric Starting Motor And Glow Plugs
(1) Heat-Start switch. (2) Magnetic switch. (3) Glow plugs. (4) Ammeter. (5) Battery. (6) Starting motor. (7) Alternator.

Charging System With Two Electric Starting Motors
(1) Magnetic switch. (2) Start switch. (3) Ammeter. (4) Battery. (5) Starting motors. (6) Alternator.

Charging System With Two Electric Starting Motors And Glow Plugs
(1) Heat-Start switch. (1) Magnetic switch. (3) Glow plugs. (4) Ammeter. (5) Battery. (6) Starting motors. (7) Alternator.

Air Starting System

The air starting motor is used to turn the engine flywheel fast enough to get the engine running.

Air Starting System (Typical Example)
(1) Starter control valve. (2) Oiler. (3) Relay valve. (4) Air starting motor.

The air starting motor can be mounted on either side of the engine. Air is normally contained in a storage tank and the volume of the tank will determine turning time of engine. The storage tank must hold this volume of air at 1720 kPa (250 psi) when filled.

For engines which do not have heavy loads when starting, the regulator setting is approximately 690 kPa (100 psi). This setting gives a good relationship between cranking speeds fast enough for easy starting and the length of time the air starting motor can turn the engine before the air supply is gone.

If the engine has a heavy load which cannot be disconnected during starting, the setting of the air pressure regulating valve needs to be higher in order to get high enough speed for easy starting.

The air consumption is directly related to speed, the air pressure is related to the effort necessary to turn the engine flywheel. The setting of the air pressure regulator can be up to 1030 kPa (150 psi) if necessary to get the correct cranking speed for a heavily loaded engine. With the correct setting, the air starting motor can turn the heavily loaded engine as fast and as long as it can turn a lightly loaded engine.

Other air supplies can be used if they have the correct pressure and volume. For good life of the air starting motor, the supply should be free of dirt and water. The maximum pressure for use in the air starting motor is 1030 kPa (150 psi). Higher pressures can cause safety problems. The 1L5011 Regulating and Pressure Reducing Valve Group has the correct characteristics for use with the air starting motor. Most other types of regulators do not have the correct characteristics. Do not use a different style of valve in its place.

Air Starting Motor
(5) Vanes. (6) Rotor. (7) Air inlet. (8) Pinion. (9) Gears. (10) Piston. (11) Piston spring.

The air from the supply goes to relay valve (3). The starter control valve (1) is connected to the line before the relay valve (3). The flow of air is stopped by the relay valve (3) until the starter control valve (1) is activated. Then air from the starter control valve (1) goes to the piston (10) behind the pinion (8) for the starter. The air pressure on the piston (10) puts the spring (11) in compression and puts the pinion (8) in engagement with the flywheel gear. When the pinion is in engagement, air can go out through another line to the relay valve (3). The air activates the relay valve (3) which opens the supply line to the air starting motor.

The flow of air goes through the oiler (2) where it picks up lubrication oil for the air starting motor.

The air with lubrication oil goes into the air motor. The pressure of the air pushes against the vanes (5) in the rotor (6). This turns the rotor which is connected by gears (9) to the starter pinion (8) which turns the engine flywheel.

When the engine starts running the flywheel will start to turn faster than the starter pinion (8). The pinion (8) retracts under this condition. This prevents damage to the motor, pinion (8) or flywheel gear.

When the starter control valve (1) is released, the air pressure and flow to the piston (10) behind the starter pinion (8) is stopped, the piston spring (11) retracts the pinion (8). The relay valve (3) stops the flow of air to the air starting motor.

Hydraulic Starting System

Hydraulic Starting System Diagram
(1) Reservoir. (2) Hand pump. (3) Pressure gauge. (4) Hydraulic starting motor. (5) Starter control valve. (6) Hydraulic pump (driven by engine timing gears). (7) Unloading valve. (8) Filter. (9) Accumulator.

The hydraulic starting motor (4) is used to turn the engine flywheel fast enough to get the engine started. When the engine is running, the hydraulic pump (6) pushes oil through the filter (8) into the accumulator (9). The accumulator (9) is a thick wall cylinder. It has a piston which is free to move axially in the cylinder. A charge of nitrogen gas (N₂) is sealed in one end of the cylinder by the piston. The other end of the cylinder is connected to the hydraulic pump (6) and the hydraulic starting motor (4). The oil from the hydraulic pump (6) pushes on the piston which puts more compression on the nitrogen gas (N₂) in the cylinder. When the oil pressure gets to 20 700 kPa (3000 psi), the accumulator (9) has a full charge. At this point the piston is approximately in the middle of the cylinder.

The unloading valve (7) feels the pressure in the accumulator (9). When the pressure is 20 700 kPa (3000 psi) the unloading valve (7) sends the hydraulic pump (6) output back to the reservoir (1). At the same time it stops the flow of oil from the accumulator (9) back to hydraulic pump (6). At this time there is 20 700 kPa (3000 psi) pressure on the oil in the accumulator (9), in the line to the unloading valve (7), in the lines to the hand pump (2) and to the hydraulic starting motor (4).

Before starting the engine, the pressure on the pressure gauge (3) should be 20 700 kPa (3000 psi). When the starter control valve (5) is activated, the oil is pushed from the accumulator (9) by the nitrogen gas (N₂). The oil flow is through the hydraulic starting motor (4), where the energy from the compression of the fluid is changed to mechanical energy for turning the engine flywheel.

Hydraulic Starting Motor

The hydraulic starting motor is an axial piston hydraulic motor. The lever for the starter control valve pushes the starter pinion (4) into engagement with the engine flywheel at the same time it opens the way for high pressure oil to get into the hydraulic starting motor.

When the high pressure oil goes into the hydraulic starter motor, it goes behind a series of pistons (2) in a rotor (1). The rotor (1) is a cylinder which is connected by splines to the drive shaft for the starter pinion (4). When the pistons (2) feel the force of the oil they move until they are against the thrust bearing (3). The thrust bearing (3) is at an angle to the axis of the rotor (1). This makes the pistons (2) slide around the thrust bearing (3). As they slide, they turn the rotor (1) which connects through the drive shaft and starter pinion (4) to the engine flywheel. The pressure of the oil makes the rotor (1) turn very fast. This turns the engine flywheel fast enough for quick starting.

Hydraulic Starting Motor
(1) Rotor. (2) Piston. (3) Thrust bearing. (4) Starter pinion. (A) Oil inlet. (B) Oil outlet.