ARMY TM 9-2815-256-24
AIR FORCE TO 38G1-96-2
MARINE CORPS TM 2815-24/5
All locations referenced herein are given facing the flywheel end (rear) of the engine.
1-8. DETAILED DESCRIPTION.
1-8.1. Turbocharger. A turbocharger, operated by exhaust gases, compresses intake air and routes it to the combustion
1-8.2. Camshaft. The camshaft is driven by an intermediate gear in the timing gear train which meshes with the
crankshaft gear. Camshaft rotates in honed machined bores in cylinder block; no bushings are used. The camshaft
lobes determine the time and rate of opening of each valve and actuates the fuel supply pump.
1-8.3. Intake and Exhaust Valves. Intake and exhaust valves are operated by cam followers, push rods, and rocker arm
assembly. Valve seat inserts in cylinder head are used for intake and exhaust valves.
1-8.4. Crankshaft. The crankshaft is a one-piece, heat treated, steel forging which operates in replaceable two-piece
front and center main bearings and five-piece rear main bearing. The rear thrust bearing has a five-piece set to support
crankshaft thrust and to limit end play.
1-8.5. Cylinder Liners and Pistons. Cylinder liners are "wet" (surrounded by coolant) and are individually replaceable.
O-rings are used to seal the connection between cylinder block and liners. Pistons are made of cast high-grade
aluminum alloy with internal ribbing. The skirt is cam ground to allow for expansion when heated during operation. The
piston crown has a cut-out swivel cup with a truncated cone in the center. Two compression rings and one oil control ring
are used. The top compression ring is a keystone type ring. All piston rings are located above the piston pin. The
hardened piston pins are fully-floating and held in position by means of retainer rings. Spray jets (piston cooling orifices)
in cylinder block direct pressurized oil to lubricate piston pins and cool pistons. Connecting rods are of forged steel and
have replaceable bushing and bearing inserts.
1-8.6. Cooling System. The cooling system consists of a radiator, water pump, cooling fan, two thermostats, and
connecting hoses. The fan is mounted on shaft of water pump and both are belt driven from the crankshaft pulley. The
thermostats control engine temperature and are installed in top of engine. The function of the cooling system is to
maintain a specific operating temperature of 175 to 185°F (79 to 85°C) for the engine.
1-8.7. Lubrication System. The lubrication system consists of oil pan (sump), a gear type pump, full flow spin-on oil filter
with built-in bypass valve, oil cooler with built-in bypass valve, pressure regulating valve, bypass valve, and the internal
1-8.8. Fuel System. The function of the fuel system is to inject a metered quantity of clean atomized fuel into the engine
cylinders at a precise time near the end of the compression stroke of each piston. The fuel system consists of the fuel
tank, fuel filter/water separator, fuel supply pump, fuel injection pump, and the fuel injectors. The fuel tank is not
mounted on the engine. The fuel supply pump is mounted to the block and is driven by the camshaft. The fuel injection
pump is mounted on the front plate and is driven by an intermediate gear in the timing gear train meshing with crankshaft
1-8.9. Electrical System. The electrical system is 24 VDC operation and consists of a battery charging alternator,
starter, externally mounted batteries, and other items as required. The battery charging alternator is mounted on front of
engine and is belt driven. When engine is operating, the battery charging alternator supplies 24 VDC to recharge the
batteries and maintain them at a full state of charge. The starter is mounted on the flywheel housing and when
energized, engages the ring gear of the flywheel to rotate the engine.