D379, D398, D399 INDUSTRIAL & MARINE ENGINES Caterpillar


Systems Operation

Usage:



Fuel System


SCHEMATIC OF FUEL SYSTEM
1. Fuel transfer pump inlet line. 2. Fuel priming pump. 3. Fuel passage. 4. Fuel return line. 5. Fuel tank. 6. Fuel transfer pump outlet line. 7. Fuel transfer pump. 8. Fuel filter housing. 9. Fuel injection pump housing.

There is one fuel injection pump and one fuel injection valve for each cylinder. The fuel injection pumps are located in the fuel injection pump housing in the Vee of the engine. The fuel injection valves are located in the precombustion chambers in the cylinder heads.

When the engine is running, fuel is pulled from fuel tank (5) through fuel transfer pump inlet line (1) by fuel transfer pump (7). The fuel is then pushed to fuel filter housing (8). Only the fuel needed goes through the fuel filters. The extra fuel goes to fuel control valve (11). The fuel from the fuel filters goes to the fuel injection pump housing (9). A passage in the housing gives fuel to each fuel injection pump. Individual fuel lines carry fuel from the fuel injection pumps to each cylinder.


FUEL FLOW THROUGH FUEL CONTROL VALVE (ENGINE RUNNING)
1. Fuel transfer pump inlet line. 2. Fuel priming pump. 3. Fuel passage. 6. Fuel transfer pump outlet line. 8. Fuel filter housing. 10. Fuel passage. 11. Fuel control valve. 13. Fuel passage.

Fuel control valve (11) controls the pressure of the fuel in the fuel system. When the fuel system is at maximum pressure, fuel control valve (11) moves and the extra fuel not needed by the engine is bypassed. A part of the bypassed fuel goes back to the inlet of the fuel transfer pump and the rest goes through fuel passage (10) and returns to the fuel tank. Any air in the fuel filter housing goes around the grooves in fuel control valve (11) to fuel passage (10) and to the fuel tank.

Fuel transfer pump (7) is located on the front, right hand side of the accessory drive housing. The pump is driven from the front of the oil pump drive gear.

Fuel priming pump (2) is located on the top of the fuel filter housing. The fuel priming pump is used to vent air from the fuel system and to fill the fuel filter housing with fuel after the filters have been changed.


SUCTION STROKE OF PRIMING PUMP
1. Fuel transfer pump inlet line. 2. Fuel priming pump. 3. Fuel passage. 6. Fuel transfer pump outlet line. 8. Fuel filter housing. 10. Fuel passage. 11. Fuel control valve. 12. Spring. 13. Fuel passage.

When the handle for the priming pump is pulled out (suction stroke), fuel control valve (11) moves toward fuel priming pump (2). This permits fuel from line (1) to flow into fuel priming pump (2).

When the handle for the fuel priming pump is pushed in (pressure stroke), the force of fuel pressure and spring (12) causes fuel control valve (11) to move away from fuel priming pump (2). With fuel control valve (11) in this position, fuel passage (3) from line (1) is closed and fuel from the priming pump goes through fuel passage (13) to fuel filter housing (8). Air in the fuel system goes through fuel passage (10) and back to the fuel tank.


PRESSURE STROKE OF PRIMING PUMP
1. Fuel transfer pump inlet line. 2. Fuel priming pump. 3. Fuel passage. 6. Fuel transfer pump outlet line. 8. Fuel filter housing. 10. Fuel passage. 11. Fuel control valve. 12. Spring. 13. Fuel passage.

Duplex Fuel Filter System

The duplex fuel filter system makes it possible to change elements for the fuel filters while the engine is running at any speed.

During normal operation, the selector lever (1) should be in the "Main Filter Run-Aux. Off" position. The fuel then will be cleaned by the elements of the main filter which are located in the right side of the filter housing. The two elements of the auxiliary filter are located in the left side of the housing.


DUPLEX FUEL FILTER
1. Selector lever. 2. Priming pump.

When the gauge for fuel pressure shows indication of minimum pressure of 20 psi (140 kPa) the main elements must be changed. While the main elements are being changed, the fuel must be cleaned by the two elements of the auxiliary filter.

Explanation of flow, with the engine running, for the selector lever positions is as follows:

AUX. VENT-MAIN RUN

Any air in the auxiliary filter will go back to the fuel tank while the main filters will filter the diesel fuel.

AUX. FILTER RUN-MAIN OFF

The auxiliary elements now filter the diesel fuel instead of the main elements.

MAIN VENT-AUX. RUN

While the auxiliary elements filter the fuel, the main filter housing will fill with fuel.

MAIN FILTER RUN-AUX. OFF

The main filters will now be filtering the fuel.

BOTH FILTERS RUN

This will permit more running time when both filter systems are almost to a condition of restriction as shown by the fuel pressure gauge.

Fuel Injection Pumps

Fuel enters the fuel injection pump housing through fuel passage (6) and enters the fuel injection pump body through inlet port (2). Pump plunger (3) and lifter (7) are lifted by lobes on camshaft (8) and always make a full stroke. Each pump measures the amount of fuel to be injected into its respective cylinder and forces the fuel out the fuel injection valve.

The quantity of fuel sent to the fuel injection valve is changed by the rotation of the pump plunger in the barrel. The pump plunger is turned by the governor action through fuel rack (5). The fuel rack turns gear segment (4) on the bottom of the pump plunger.


FUEL INJECTION PUMP
1. Pump. 2. Inlet port. 3. Pump plunger. 4. Gear segment. 5. Fuel rack. 6. Fuel passage. 7. Lifter. 8. Camshaft.

Fuel Injection Valve


FUEL INJECTION VALVE CROSS SECTION
1. Fuel injection line. 2. Nut. 3. Body. 4. Nozzle assembly.

High pressure fuel from the fuel injection pumps is moved through the fuel injection lines to the fuel injection valves. As high pressure fuel enters the nozzle assembly, the check valve in the nozzle opens and permits the fuel to enter the precombustion chamber. The fuel injection valve gives the correct characteristics (spray pattern) for good fuel combustion.

Hydra-Mechanical Governor

The governor controls the amount of fuel needed to keep the engine at the desired rpm.

The supply of engine oil to the governor is sent through the oil manifold (A) of the fuel pump and governor drive housing. Drilled passages (B) send oil to the upper housing and reservoir of the governor. The oil reservoir in the governor drive housing gives a supply of oil for the gear-type oil pump (C). The pressure oil from oil pump (C) gives assistance to the governing action.


GOVERNOR OIL PUMP SUPPLY
A. Oil manifold. B. Drilled passages. C. Oil pump.

The governor has a governor weight assembly (9), which is driven by the engine through the drive pinion (22). The seat (10), valve (8), and piston (13) are connected to fuel rack (21) through pin assembly (18) and lever (20). Pressure oil for the governor comes from the oil pump in the governor. Pressure oil goes through a passage and around sleeve (14). The governor control, controls only the compression of governor spring (7). Compression of the spring always pushes down to give more fuel to the engine. The centrifugal force (rotation) of weight assembly (9) 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).

When the engine load increases, the engine rpm decreases and the rotation of weight assembly (9) will get slower. (The governor weights will move toward each other). Governor spring (7) moves seat (10), and valve (8) down. This lets oil flow around valve (8) and through oil passage (11) to fill the chamber behind piston (13). This pressure oil pushes piston (13) and pin assembly (18) down to give more fuel to the engine. (The upper end of valve (8) stops the flow of oil through the top of the piston, around the valve.) Engine rpm increases until the rotation of weight assembly (9) is fast enough to be in balance with the force of governor spring (7). When these two forces are in balance, the engine will run at the desired rpm (governed rpm).


GOVERNOR
1. Shutoff shaft. 2. Collar. 3. Adjusting screw. 4. Stop bar. 5. Lever assembly. 6. Seat assembly. 7. Governor spring. 8. Valve. 9. Weight assembly. 10. Seat. 11. Oil passage. 12. Cylinder. 13. Piston. 14. Sleeve. 15. Oil pump gear. 16. Governor drive housing. 17. Oil pump cover. 18. Pin assembly. 19. Shaft assembly. 20. Lever. 21. Fuel rack. 22. Drive pinion.

When the engine load decreases, engine rpm increases and weight assembly (9) turns faster. This will move seat (10) and valve (8) up. This stops oil flow from going around the bottom of valve (8). Pressure oil above piston (13) goes out around the top of valve (8). Now, the pressure oil between sleeve (14) and piston (13) pushes the piston and pin assembly (18) up to give less fuel to the engine. Engine rpm decreases until the centrifugal force (rotation) of weight assembly (9) is in balance with the force of governor spring (7). When these two forces are in balance, the engine will run at the desired rpm (governed rpm).

When the engine is started, the plunger for the speed limiter puts a restriction on the movement of the governor control. When oil pressure increases to the operating level, the governor control can be moved to the HIGH IDLE position.

When engine rpm is at LOW IDLE, a spring-loaded plunger in lever assembly (5) 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.

Oil from the governor pump gives lubrication to the bearings of the governor weights. The other parts of the governor get lubrication from "splash-lubrication" (oil thrown by other parts). Oil from the governor runs back into the drive housing for the fuel injection pumps.

Fuel Ratio Control

The fuel ratio control automatically causes a restriction to 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 good fuel combustion. The fuel ratio control keeps engine performance high so that the amount of black exhaust gases are at a minimum.

An override lever (1) is used to permit rack movement when the engine is started at cool temperatures. After the engine starts, the override automatically moves to the RUN position.

Collar (6) mechanically fastens to the fuel rack through the governor. The head of bolt (7) engages in collar (6). An air line connects the chamber of above diaphragm (5) with the inlet manifold.


CROSS SECTION OF FUEL RATIO CONTROL
1. Lever. 2. Housing. 3. Spring. 4. Spring. 5. Diaphragm. 6. Collar. 7. Bolt.

When the operator moves the governor control to increase engine rpm, the governor spring moves collar (6). This causes the collar to contact the head of bolt (7). The bolt causes a restriction to the movement of the collar until inlet manifold air pressure in the chamber above the diaphragm is high enough to move diaphragm (5), spring (4), and bolt (7). This will let the rack move to increase the fuel to the engine at a rate equal to (the same as) the air available for good combustion.

Air Inlet And Exhaust System


AIR INLET AND EXHAUST SYSTEM
1. Exhaust manifolds. 2. Right cylinders. 3. Diffuser plate. 4. Right turbocharger impeller. 5. Exhaust elbow. 6. Left cylinders. 7. Turbocharger turbine wheels. 8. Left turbocharger impeller. 9. Aftercooler.

The air inlet and exhaust system has two turbochargers and an aftercooler (9). The right turbocharger uses exhaust gas from the right side to drive the turbine (7), but gives air to the left cylinders (6). The left turbocharger uses exhaust gas from the left side to drive turbine (7) and gives air to the right cylinders (2).

When the engine load increases, the volume of exhaust gases increase and cause the turbine in the turbocharger to turn faster. This will cause the impeller (4 & 8) to turn faster and increase the inlet manifold air pressure. As the pressure of the air increases, the temperature of the air also increases. An aftercooler is installed between the turbochargers and the inlet manifold to help cool the inlet air.

A diffuser plate (3) in the center of exhaust elbow (5) keeps the exhaust gases from the turbocharger outlets apart to reduce exhaust back pressure.

Aftercooler

The aftercooler is installed on the top of the flywheel housing. The aftercooler has two separate cores, one for each inlet manifold. Air is pushed by the turbocharger into the aftercooler and the air goes around the fins of the aftercooler core. Coolant constantly flows through the tubes in the aftercooler core to remove the heat from the air. The cooler air, which is heavier (more dense), will permit more fuel to burn and give an increase in power.

Valves And Valve Mechanism

The valves and valve mechanism control the flow of inlet air and exhaust gases into and out of the cylinder.

The intake and exhaust valves are opened and closed by movement of these components; crankshaft, camshaft, lifters, push rods, rocker arms, and valve springs.

The gear on the crankshaft is timed to and drives the camshaft gear attached to the camshaft. When the camshaft turns, the lobes on the camshaft cause the valve lifters to move up and down. The valve lifters move the push rods, which move the rocker arms, Movement of the rocker arms causes the intake and exhaust valves to open and close in the firing order (injection sequence) of the engine. Valve springs for each valve close the valve and holds them in the closed position.


VALVE AND VALVE MECHANISM (Cross Section, Single Spring Type)
1. Rocker arm. 2. Locks. 3. Spring. 4. Retainer. 5. Guide. 6. Valve rotator. 7. Push rod. 8. Valve. 9. Bracket assembly. 10. Connector. 11. Valve lifter.

Each valve has a valve rotator under the valve spring. The valve rotator causes the valve to turn approximately three degrees each time the valve opens and closes. This action of the valve keeps carbon deposits off of the valve face and valve seat.

Turbocharger

The turbocharger are installed at the rear of the exhaust manifolds. All of the exhaust gases from the engine go through the turbochargers.

The exhaust gases enter turbine housing (5) and go through the blades of turbine wheel (6), causing the turbine wheel and compressor wheel (1) to turn.

When the compressor wheel turns, it pulls filtered air from the air cleaners through the compressor housing air inlet. The air is put in compression by action of the compressor wheel and is pushed to the inlet manifold of the engine.


CROSS SECTION OF TURBOCHARGER
1. Compressor wheel. 2. Compressor housing. 3. Thrust bearing. 4. Lubrication inlet port. 5. Turbine housing. 6. Turbine wheel. 7. Air inlet. 8. Exhaust outlet. 9. Sleeve. 10. Shaft journal bearings. 11. Sleeve. 12. Exhaust inlet.

When the engine load increases, more fuel is injected into the engine cylinders. The volume of exhaust gas increases which causes the turbocharger turbine wheel and compressor impeller to turn faster. The increased rpm of the impeller increases the quantity of inlet air. As the turbocharger provides additional inlet air, more fuel can be burned. This results in more horsepower from the engine.

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.


NOTICE

If the high idle rpm or the rack setting is higher than given in the RACK SETTING INFORMATION (for the height above sea level at which the engine is operated), there can be damage to engine or turbocharger parts.


The bearings for the turbocharger use engine oil for lubrication. The oil comes in through lubrication inlet passage (4) and goes through passages in the center section for lubrication of the bearings. Oil from the turbocharger goes out through the lubrication outlet passage in the bottom of the center section and goes back to the engine lubrication system.

Lubrication System


SCHEMATIC FLOW DIAGRAM OF THE LUBRICATION SYSTEM (Pressure oil flow is shown in light grey, suction oil, return oil or splash-lubricated points are shown in dark grey)
1. Oil return line for turbocharger. 2. Oil supply line for turbocharger. 3. Oil manifold. 4. Booster oil pump for governor. 5. Valve mechanism. 6. Oil manifold. 7. Oil cooler. 8. Filter housing. 9. Camshaft bearings. 10. Main bearings of crankshaft. 11. Connecting rod bearings. 12. Piston cooling jets. 13. Pump of prelube system. 14. Pressure regulating valve. 15. Suction bell. 16. Single section oil pump. 17. Oil pan base.

The lubrication system uses a single section oil pump to send lubrication oil to the engine components. The 16 cylinder engines have a prelubrication pump in addition to the main oil pump. The prelubrication pump is used to give lubrication to the engine components before the engine is started.

Oil from the oil pan base (17) is pulled through suction bell (15) and pipe to oil pump (16). The oil pump then pushes the oil to oil cooler (7). The pressure regulating valve (14) between the oil pump and the oil cooler controls the maximum pressure of the oil to the engine. Oil from the oil cooler goes to oil filter housing (8). An oil filter relief valve in the oil filter housing controls the flow of oil in the housing. When the oil is cold or the oil filters have a restriction, the relief valve opens and oil flows around the oil filter elements to oil manifold (6). When the oil gets warm, and there is no restriction to the oil filters, the relief valve is closed and oil flows through the oil filters to the oil manifold.

A service indicator for the oil filters is on top of the oil filter housing. When the red indicator button goes up approximately to the center of the clear indicator with the oil warm the oil filter elements must be changed.

Oil from the oil manifold flows through oil passages and lines to the inside and outside components of the engine.

The oil in oil manifold (6) goes to camshaft bearings (9), crankshaft main bearings (10), connecting rod bearings (11), valve mechanism (5), piston cooling jets (12), and to oil manifold (3).

The oil in oil manifold (3) goes to the turbocharger, governor, and fuel injection pump housing. When the engine is equipped with an oil pressure shutoff or reversal protection control, they also get oil from oil manifold (3). On 8 and 12 cylinder engines there is a turbocharger quick lubrication valve that gives immediate pressure oil to the turbochargers at engine start up. Unfiltered oil from the oil cooler goes through an oil line to the turbocharger quick lubrication valve at engine start up. When the oil in oil manifold (3) gets pressure, the lubrication valve shuts off the unfiltered oil and the turbochargers now get filtered oil from oil manifold (3).

The rear timing gear bearings get pressure oil through passages from the rear camshaft and crankshaft bearings. The gears get lubrication from the return oil from the turbochargers.


SCHEMATIC FLOW DIAGRAM OF THE FRONT ACCESSORY DRIVE
6. Oil manifold. 18. Water pump gear. 19. Oil pump gear. 20. Main idler gear. 21. Balancer gear. 22. Crankshaft gear. 23. Idler gear. 24. Idler gear.

The front accessory drive gets pressure oil from oil manifold (6) through a passage from the front crankshaft main bearing. Steel tubes in the front accessory drive housing give oil to all of the bearings for the gears.

Duplex Oil Filter System

The duplex oil filters permit the main oil filters to be changed while the engine is in operation.

The duplex oil filter system has two auxiliary oil filters (5), a filter vent valve (2) and selector valve (1).

The selector valve (1) is used to change the flow of engine oil from the main oil filters (3) to the auxiliary oil filters (5). The filter vent valve (2) permits air to be vented from the oil filters before the selector valve is moved.


DUPLEX LUBE FILTER SYSTEM
1. Selector (diverter) valve. 2. Filter vent valve. 3. Main filter. 4. Filter pressure gauges. 5. Auxiliary filter. 6. Adapting oil lines.

When the selector valve handle is parallel with the engine crankshaft, the flow of oil is to the main oil filters. When the handle is turned 90° away from the engine, the oil flow is to the auxiliary oil filters.


SCHEMATIC FLOW DIAGRAM OF DUPLEX LUBRICATION FILTER SYSTEM
1. Selector (diverter) valve. 2. Filter vent valve. 3. Main filter. 4. Filter pressure gauges. 5. Auxiliary filter. 7. Check valves. 8. Vent lines to engine crankcase from filters. 9. Pump for engine oil. 10. Oil cooler.

Prelubrication System (16 Cylinder Engines Only)

The prelubrication system has an oil pump (1) that is turned by a motor (3). The motors used are: a 115/230 VAC, 24 VDC, 32 VDC, and an air motor. The motor and pump are mounted on the right side of the engine. The pump pulls oil from the oil pan base and then pushes the oil through a tube that connects to the engine oil line at tee (2). Check valve (4) is used to prevent the flow of engine oil backwards through the prelubrication pump to the oil pan base.


COMPONENT LOCATION
1. Oil pump. 2. Tee. 3. Electric motor. 4. Check valve.

When you start the engine, the prelubrication pump will give lubrication to the engine before the starting motors turn. When oil pressure at the oil lines to the turbochargers is 1 to 3 psi (7 to 20 kPa), a pressure switch will close and activate the starting motors. When the engine starts and the start switch or air valve is released the prelubrication pump stops.

Cooling System


FLOW OF COOLANT IN RADIATOR COOLING SYSTEM
1. Aftercooler. 2. Exhaust manifold. 3. Tubes. 4. Water manifold. 5. Regulator housing. 6. Radiator. 7. Bypass line. 8. Water pump. 9. Cylinder head. 10. Engine oil cooler. 11. Junction housing. 12. Bottom passage. 13. Flywheel housing. 14. Top passage.

Engine Jacket Water Cooling System

The two most used methods to remove heat from the engine jacket water are the radiator and the heat exchanger. The heat exchanger method must have an expansion tank to give room for the expansion of the coolant. The radiator has a top tank to give room for the expansion of the coolant.

A gear driven centrifugal-type water pump is used to move the coolant through the engine jacket water cooling system. The water pump is on the right side of the engine on the rear of the accessory drive housing.

The flow of coolant through the engine is as follows: Coolant from radiator (6) or expansion tank (16) is pulled through the inlet line by water pump (8). The water pump then pushes the coolant to engine oil cooler (10). From the oil cooler the coolant goes to top passage (14) in flywheel housing (13).

Coolant goes through the top passage in the flywheel housing to junction housing (11) on the left side. The coolant turns 180 degrees in the junction housing cover and goes into bottom passage (12) in the flywheel housing.


FLOW OF COOLANT IN HEAT EXCHANGER COOLING SYSTEM
1. Aftercooler. 2. Exhaust manifold. 3. Tubes. 4. Water manifold. 5. Regulator housing. 8. Water pump. 9. Cylinder head. 10. Engine oil cooler. 11. Junction housing. 12. Bottom passage. 13. Flywheel housing. 14. Top passage. 15. Water cooled turbocharger shield. 16. Expansion tank. 17. Engine jacket water heat exchanger.

NOTE: On engines equipped with a jacket water aftercooler, part of the coolant goes to the aftercooler through a pipe from the top passage of the junction housing. The coolant goes through the front core of the aftercooler, and through a pipe to the rear core. From the rear aftercooler core the coolant goes through a pipe to the bottom passage of the junction housing. A plate with an orifice is installed between the junction housing and the junction housing cover, to cause the coolant to flow through the aftercooler.

In the bottom passage of the flywheel housing part of the coolant goes to the left side of the cylinder block. The remainder of the coolant goes across the flywheel housing into the right side of the cylinder block. The coolant then flows through the cylinder block, around the cylinder liners and into cylinder heads (9). Lines from the rear of the cylinder block let coolant go to water cooled turbocharger shield (15). Coolant goes from the shield through lines to either water cooled or water shielded exhaust manifolds (2).

Coolant from the cylinder heads goes through tubes (3) to the exhaust manifold shields or the water cooled exhaust manifolds and then to the front of the engine to water manifold (4).

Coolant goes from the water manifold to regulator housing (5). The regulators in the housing control the flow of coolant to the radiator or heat exchange to control the temperature in the cooling system.

When the system has a radiator, there is a bypass line (7) from the inlet side of the regulator housing to the inlet pipe for the water pump. When the system has a heat exchanger and expansion tank, there is a bypass passage from the inlet side of the regulator housing to the expansion tank. In either system when the temperature of the coolant is not high enough to open the regulators, coolant will bypass the radiator or heat exchanger to permit quick warm-up of the engine.

Coolant Level Switch

Some systems with expansion tanks have a coolant level switch for the purpose of checking coolant level in the system. The coolant level can be seen through the glass on earlier type switches. The float (1) which operates the switch (2) also can be seen. The float position on the later type switch is shown by the operating arm (3).

When the coolant level gets too low, the switch can be used to sound an alarm, light a warning light or operate a device to stop the engine.


COOLANT LEVEL SWITCH (Earlier Type)
1. Float. 2. Switch.


COOLANT LEVEL SWITCH (Later Type)
2. Switch. 3. Operating arm.


FLOW OF COOLANT IN SEA WATER COOLING SYSTEM
17. Engine jacket water heat exchanger. 18. Sea water pump. 19. Aftercooler inlet elbow. 20. Outlet elbow. 21. Marine gear oil cooler. 22. Flange. 23. Water outlet connection. 24. Flange.

Sea Water And Separate Circuit Aftercooler Water Systems

Sea Water System

The sea water aftercooler system uses sea water (water that is not treated) to remove heat from the aftercooler cores and other cooling system components. A gear driven, centrifugal-type water pump is used to move the sea water through the system. The pump is on the left side of the engine on the accessory drive housing. Zinc rods are installed in the sea water system to help prevent corrosion of the system components. These rods must be replaced from time to time to keep the resistance of corrosion high. The plugs for the zinc rods have red paint for easy identification.

Sea water pump (18) pulls water through the inlet pipe and then pushes it through a pipe to aftercooler inlet elbow (19). A part of the water at the elbow goes to the front aftercooler core and through a pipe to the rear aftercooler core, and the remainder of the water goes through a pipe to outlet elbow (20). The restriction of the pipe to the outlet elbow will cause most of the water to go through the aftercooler. Water from the rear aftercooler core goes to the outlet elbow and mixes with the water from the inlet elbow.

NOTE: There is a plate with an orifice installed between the rear aftercooler core and the outlet elbow to help keep the aftercooler cores full of water.


FLOW OF COOLANT IN SEPARATE CIRCUIT COOLING SYSTEM
19. Aftercooler inlet elbow. 20. Outlet elbow. 21. Marine gear oil cooler. 22. Flange. 23. Water outlet connection. 24. Flange. 25. Fresh water pump. 26. Keel cooler. 27. Expansion tank.

Part of the water at the outlet elbow goes to marine gear oil cooler (21), and the remainder goes through flange (22) to water outlet connection (23). Water from the marine gear oil cooler goes to flange (24). There is a plate with an orifice installed between the aftercooler outlet elbow and flange (22) to make the water go through the marine gear oil cooler.

Water from the water outlet connection goes to the tube side of the engine jacket water heat exchanger (17). The water goes through the heat exchanger and then to the sea water outlet (overboard discharge).

Separate Circuit System

The separate circuit aftercooler system uses fresh water (water that is treated) to remove heat from the aftercooler cores and other cooling system components. A gear-driven centrifugal-type water pump is used to move the fresh water through the system. The pump is on the left side of the engine on the accessory drive housing.

Fresh water pump (25) pulls coolant through the inlet pipe and then pushes it through a pipe to the front aftercooler core. The coolant flows through the front aftercooler core and then through the rear aftercooler core to outlet elbow (20). Part of the coolant at the outlet elbow goes to marine gear oil cooler (21) and the remainder goes through flange (22) to water outlet connection (23). Coolant from the marine gear oil cooler goes to flange (24). There is a plate with an orifice installed between the aftercooler outlet elbow and flange (22) to make the coolant go through the marine gear oil cooler.

Coolant from the water outlet connection goes to keel cooler (26) or a fresh water heat exchanger which will remove the heat from the coolant. The coolant then returns to the water pump inlet pipe. An expansion tank (27) is installed in the inlet pipe to give room for expansion of the coolant.

Basic Block

Cylinder Block, Heads And Liners

The cylinder block is a 60° vee. There is a counterbore in the top of the block for each cylinder liner. The bottom of the counterbore is the support for each liner. Covers on the side of the cylinder block permit inspection or replacement of the connecting rod and main bearings without removal of the oil pan base.

The engine has one cylinder head for each two cylinders. The block has studs to fasten the cylinder heads.

Coolant in the engine flows around the liners to remove heat from them. Three o-ring seals at the bottom and a filler band at the top of each cylinder liner make a seal between the cylinder liner and the cylinder block.

Pistons, Rings And Connecting Rods

The piston has three rings; two compression rings and one oil ring. All rings are located above the piston pin bore. The two compression rings seat in an iron band which is cast in the piston. The oil ring is spring loaded. Holes in the oil ring groove return oil to the crankcase.

The full-floating piston pin is held in place by two snap rings which fit in grooves in the pin bore.

A steel heat plug in the top of the piston prevents erosion (wearing away) of the top of the piston at the point of highest heat.

Piston cooling jets, located on the bottom of the valve lifter brackets, throw oil to cool and give lubrication to the piston components and cylinder walls.

The connecting rods and caps are cut at an angle which let the piston and connecting rod assembly be removed up through the cylinder liner. The connecting rod bearings are held in location with a tab that fits in a groove in the connecting rod and cap. The connecting rods must be installed with the part number toward the radius in the crankshaft journal.

Crankshaft

Combustion forces in the cylinder are changed into usable rotating power by the crankshaft. The crankshaft has a gear on each end. The gear at the front drives the gears in the accessory drive. The gear at the back drives the engine camshaft and the fuel injection pump camshaft. The crankshaft end play is controlled by thrust bearings on the rear main bearing cap. For an opposite rotation engine the crankshaft is turned end for end.

Timing Gears

The timing gears are in a compartment at the rear of the cylinder block. Their cover is the front face of the flywheel housing. The timing gears keep the rotation of the crankshaft, camshaft, balancers (8 cylinder engine), fuel pump and governor drive in the correct relation to each other. The timing gears are driven by a gear in front of the rear flange of the crankshaft.


TIMING GEARS (8 Cylinder Engine Illustrated)
1. Fuel pump and governor drive gear. 2. Camshaft cluster gear. 3. Balancer gear (8 cylinder engines only). 4. Crankshaft gear.

The crankshaft gear (4) turns the camshaft cluster gear (2). This gear turns the balancer gear (3) (8 cylinder engine) and gear (1) of the fuel pump and governor drive.

The small cluster gear of the camshaft is held to the camshaft with a key, plate and bolts.

Vibration Damper

The force from combustion in the cylinders will cause the crankshaft to twist. This is called torsional vibration. If the vibration is too great, the crankshaft will be damaged. The vibration damper limits torsional vibrations to an acceptable amount to prevent damage to the crankshaft.

The vibration damper is installed on the front of the crankshaft. The damper has a weight in a metal housing. The space between the weight and the housing is filled with a thick fluid. The weight moves in the housing to limit the torsional vibration.


CROSS SECTION OF A TYPICAL VIBRATION DAMPER
1. Solid cast iron weight. 2. Space between weight and case. 3. Case.

The 8 cylinder engine has a short, rigid crankshaft and does not need a vibration damper except for some special applications. The 12 cylinder engine has one vibration damper. 16 Cylinder Engines Serial No. 35B1 thru 35B1275, 91B1 thru 91B633 and 91B732 thru 91B755 have one vibration damper. 16 Cylinder Engines Serial No. 35B1276-Up, 91B634 thru 91B731 and 91B756-Up have two vibration dampers.

Front Accessory Drive

The front accessory drive gives a location to operate accessories such as a sea water pump, fresh water pump, air compressor, hydraulic pump, and alternator. The engine oil pump, fuel transfer pump, and jacket water pump are also driven by the front accessory drive.

The direction of rotation of the accessory drive is the same for standard or opposite rotation engines.

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 250 psi (1720 kPa) when filled.

For engines which do not have heavy loads when starting, the regulator setting is approximately 100 psi (690 kPa). 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 can not 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 150 psi (1030 kPa) 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 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 150 psi (1030 kPa). 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 (Ingersoll-Rand Motor Shown)
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) pulls back 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 3000 psi (20 700 kPa), 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 3000 psi (20 700 kPa) 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 3000 psi (20 700 kPa) 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 3000 psi (20 700 kPa). 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


HYDRAULIC STARTING MOTOR
1. Rotor. 2. Piston. 3. Thrust bearing. 4. Starter pinion. A. Oil inlet. B. Oil outlet.

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 starting 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.

Electrical System

The electrical system can have 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.

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

The starting circuit can have 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-type belts from a pulley on the accessory drive. 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 the 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.


5S9088 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.

Starting System Components

Starting Motor

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

The starting motor has a solenoid. When the start switch is activated, electricity from the electrical system will cause the solenoid to move the starter pinion to engage 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 starting motor. When the start switch is released, the starter pinion will move away from the ring gear of the flywheel.


STARTING MOTOR
1. Field. 2. Solenoid. 3. Clutch. 4. Pinion. 5. Commutator. 6. Brush assembly. 7. Armature.

Solenoid

A solenoid is a magnetic switch that uses low current to close a high current circuit. The solenoid has an electromagnet with a core (6) which moves.


SCHEMATIC OF A SOLENOID
1. Coll. 2. Switch terminal. 3. Battery terminal. 4. Contacts. 5. Spring. 6. Core. 7. Component terminal.

There are contacts (4) on the end of core (6). The contacts are held in the open position by spring (5) that pushes core (6) from the magnetic center of coil (1). Low current will energize coil (1) and make a magnetic field. The magnetic field pulls core (6) to the center of coil (1) and the contacts close.

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

The circuit breaker is a safety 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 completes the electric circuit 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 after it cools. Push the reset button to close the contacts and reset the circuit breaker.


CIRCUIT BREAKER SCHEMATIC
1. Reset button. 2. Disc in open position. 3. Contacts. 4. Disc. 5. Battery circuit terminals.

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.

Glow plugs are provided for low temperature starting conditions. Systems without glow plugs are usually used where ideal starting conditions exist or where an Automatic Start-Stop system is used.

A fuel or oil 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 or oil 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 Service Manual for the generator or to the Attachment Sections of this manual, for this information.

The chart gives the correct wire sizes and color codes. Make reference to the description in Systems Operation for the function of each of the components.

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. 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. Heat-Start switch. 2. Magnetic switch. 3. Glow plugs. 4. Ammeter. 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.

(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. 2. Magnetic switch. 3. Glow plugs. 4. Ammeter. 5. Battery. 6. Starting motors. 7. Alternator.

(Prelubrication Pump)


230V-AC PRELUBRICATION PUMP
1. Oil pressure switch. 2. Start switch. 3. Magnetic switch. 4. 230V-AC Prelubrication pump. 5. Battery. 6. Starting motor. 7. Relay.


24-30-32 V-DC PRELUBRICATION PUMP
1. Oil pressure switch. 2. Start switch. 3. Magnetic switch. 4. 24-30-32 V-DC Prelubrication pump. 5. Battery. 6. Starting motor.

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.

(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. 2. Magnetic switch. 3. Glow plugs. 4. Ammeter. 5. Battery. 6. Starting motors. 7. Alternator.

(Prelubrication Pump)


230V-AC PRELUBRICATION PUMP
1. Oil pressure switch. 2. Start switch. 3. Magnetic switch. 4. 230V-AC Prelubrication pump. 5. Battery. 6. Starting motor. 7. Relay.


24-30-32 V-DC PRELUBRICATION PUMP
1. Oil pressure switch. 2. Start switch. 3. Magnetic switch. 4. 24-30-32 V-DC Prelubrication pump. 5. Battery. 6. Starting motor.

Engine Protection Devices

Shutoff Control

A shutoff control for overspeed (engine running too fast) and low oil pressure is provided for industrial engines. An attachment is also available to provide protection for high coolant temperature and is used with the shutoff control.

V12 and V16 Marine Engines are equipped with reversal protection in addition to overspeed. The shutoff for reversal protection is available as an attachment for V8 Marine Engines. These reversal protection controls do not have protection for low oil pressure.

The shutoff control (1) is installed in the V of the engine at the rear of the governor. The control is driven from the fuel pump and governor drive shaft.

Engine oil pressure is used to activate the low oil pressure shutoff control. The location of plug (2) is for the connection of a shutoff control valve for water temperature. The line (4) supplies engine oil pressure to the shutoff control.


SHUTOFF CONTROL
1. Shutoff control. 2. Plug (pressure oil connection to water temperature shutoff). 3. Fuel rack shutoff reset cable assembly. 4. Pressure oil line to shutoff control. 5. Reset button. 6. Emergency manual shutoff button.

The overspeed shutoff part of the control stops the engine mechanically in the event of engine overspeeding.

Controls equipped with reversal protection are activated by low oil pressure only when the engine runs in reverse.

The emergency manual shutoff button (6) works with the overspeed shutoff and provides the operator with an emergency shutoff control.

NOTE: DO NOT use the emergency manual shutoff button to shut down the engine in normal operation. This will cause more than normal wear on the overspeed shutoff parts.

Reset button (5) is used to set the control after the engine has been stopped by the control because of low oil pressure. It is also used after the engine has been stopped because of high water temperature.

NOTE: It is not necessary to set the control after a normal engine stop.

The shutoff control parts get lubrication from leakage past the oil pressure shutoff piston. Return oil goes through two drilled holes in the bottom of the housing.

Shutoff Control Operation

Low Oil Pressure Shutoff and Water Temperature Shutoff

The oil pressure control will stop the engine when the lubrication oil pressure drops below 12 ± 3 psi (85 ± 20 kPa). It will also stop the engine when high water temperature opens a shutoff control valve which causes low oil pressure to the control.


SHUTOFF CONTROL (Cross Sectional Side View; Normal Operation)
1. Worm shaft. 2. Slide follower. 3. Slide follower shaft. 4. Cover. 5. Guide. 6. Piston. 7. Spring. 8. Release rod.

Under normal engine operation, engine lubricating oil goes through line (4). (See illustration of Shutoff Control.) This oil goes to cover (4) and against control piston (6). (See illustration Shutoff Control, Cross Sectional Side View; Normal Operation.)

One end of slide follower (2) is engaged with guide (5). The follower is free to pivot about slide follower shaft (3) in the housing and is activated by the movement of guide (5).

Worm shaft (1) is turned by the shutoff drive which is turned by the fuel pump and governor drive shaft. Any time the engine is running the control is in operation.

When the pressure of the engine oil is normal, piston (6) is held against guide (5) putting spring (7) in compression and keeps slide follower (2) out of contact with worm shaft (1).


SHUTOFF CONTROL (Top View; Normal Operation Position)
1. Worm shaft. 2. Slide follower. 3. Slide follower shaft. 5. Guide. 8. Release rod. 9. Pin. 10. Release latch. 11. Spring.

When the pressure of the lubrication oil drops below normal operating range, the oil pressure on piston (6) will also drop and spring (7) will force guide (5) and piston (6) to the stop position and cause slide follower (2) to turn on shaft (3) and contact worm shaft (1).

The slide follower (2) will move the length of worm portion of shaft (1) when slide follower (2) is engaged with worm shaft (1). As the follower comes close to the end of its movement, pin (9) on the follower makes contact with release latch (10).

The release latch is then moved out of engaged position and releases rod (8) which moves outward by force of spring (11).


SHUTOFF CONTROL (Side View; Shutoff Operation Position)
1. Worm shaft. 2. Slide follower. 3. Slide follower shaft. 5. Guide. 6. Piston. 7. Spring. 8. Release rod.


SHUTOFF CONTROL (Top View, Shutoff Operation Position)
1. Worm shaft. 2. Slide follower. 8. Release rod. 9. Pin. 10. Release latch. 11. Spring.

Release rod (8) moves to contact plunger (12) in the rear of the governor drive housing. The plunger then moves forward to contact the lever assembly in the governor drive housing to move the fuel rack to the fuel off position and stop the engine.


RACK SHUTOFF
12. Plunger.

Engine Reversal Protection Control

The shut off control for engine reversal protection is the same as the control for low oil pressure except the threads on worm shaft (1) go in the opposite direction. Low oil pressure will shut off the engine only if the engine runs in reverse. The oil pressure will be low because the engine oil pump will not give oil pressure in reverse.

Overspeed Shutoff


OVERSPEED CONTROL
1. Carrier assembly. 2. Rotating weight. 3. Release latch. 4. Release rod.

When an overspeed (engine running too fast) condition has happened, the overspeed shutoff control, located in the shutoff control housing, will activate the release rod. The release rod moves the fuel rack to the off position to stop the engine.

Overspeed carrier assembly (1) is driven by gears and the shutoff drive which is driven by the fuel pump and governor drive shaft. When the engine is running the overspeed carrier will turn. A rotating weight (2) in the carrier flange is held toward the center of the carrier shaft by an adjustment screw, spring and nut.

When the engine rpm increases, the centrifugal force acting on the weight increases, and the weight moves out of the carrier flange. This movement of the weight continues until the spring force (restriction of weight movement outward) is equal to the force moving the weight out.

When the engine overspeeds, the weight will move out of the carrier flange and make contact with release latch (3). Release latch (3) will move and permit release rod (4) to move down which moves the shutoff lever and the fuel rack to the fuel OFF position.

Emergency Manual Shutoff Button


EMERGENCY SHUTOFF
1. Spring loaded weight. 2. Carrier assembly. 3. Pin 4. Plunger. 5. Button.

Manual shutoff button (5) is used only to stop the engine in an emergency. DO NOT use the shutoff button to stop the engine in normal operation. In normal operation, remove all of the load from the engine and make a reduction in engine rpm to low idle before the engine is stopped.

In an emergency where the engine must be shut down immediately, push the emergency shutoff button and hold it in until the release rod has been released.

When button (5) is pushed, it will move plunger (4) against pin (3) which will force weight (1) out of carrier assembly (2). This makes the shutoff control operate the same as an overspeed (engine running too fast) condition.

Setting The Shutoff Control

When the engine has been shut-down by the shutoff control, the reason for the shut-down must be corrected and the control set again before the engine can be started.

Setting After Overspeed and Emergency Manual Shut-down

The release rod is set by moving the lever (1). The engine now can be started.


SHUTOFF SETTING CONTROL
1. Lever.

Setting After Low Oil Pressure or High Water Temperature Shut-down

Push reset button (4) on the top of the shutoff control housing. This moves control piston (3) and pin against slide follower guide (1). The movement of the guide turns slide follower (2) away from the end of the worm shaft. This permits the spring to move the slide follower to the start of the worm shaft threads.

Latch the release rod (5) by pulling on the shutoff setting control lever.

The engine can now be started.


SHUTOFF SETTING CONTROL
1. Slide follower guide. 2. Slide follower. 3. Control piston. 4. Reset button. 5. Release rod.

NOTE: In cold weather operation, it may be necessary to push the reset button (4) while cranking the diesel engine to prevent activating the shutoff control. This is necessary as the oil pressure will not increase to the operating range fast enough because of the longer cranking period needed under these conditions.

Under conditions of normal operation, pressure of the lubrication oil will increase to the operating range before the follower has moved to the limit of travel and activates the release latch and rod.

Caterpillar Information System:

D379, D398, D399 INDUSTRIAL & MARINE ENGINES Pressure Accumulator For Hydraulic Starter
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Hand Pump For Hydraulic Starter
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Charging Pump For Hydraulic Starting
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Hydraulic Starting Motor
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Air Starting Motor
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Pressure Regulating Valve For Air Starting Motor
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Starter Solenoids
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Starter Motor
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Magnetic Switch
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Generator Regulator
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Alternator Regulators
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Alternators And Regulators
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Testing And Adjusting
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Cable Adjustment<BR> (Air Inlet Shut-off)
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Governor
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Governor Drive Upper Housing
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Governor Drive Upper Housing
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Governor Air Actuators
D379, D398, D399 INDUSTRIAL & MARINE ENGINES 3N9125 Air Actuator Group
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Magnetic Pickup
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Shut-Off Solenoids
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Shutoff Valve For Water Temperature
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Rack Shut Off Cylinder 1N5073 and 5N5762
D379, D398, D399 INDUSTRIAL & MARINE ENGINES Air Inlet Shut Off
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