Engine External Components.

*TM 9-2815-213-34

degrees. Coolant flows from the thermostat housing to

sists of a hand-priming pump which pumps fuel into the

the expansion tank in the radiator.

intake manifold, a glow plug which is electrically heated

(4) Air Intake System. The V8-300 diesel engine is a

by the battery, and a switch to turn on the glow plug while

fuel is pumped into the intake manifold. The fuel burns in

naturally aspirated engine. The air flows from the air

the intake manifold and heats the air.

cleaner through connections into the air intake manifold

and is drawn into the combustion chamber.

(5) Ventilation System. Ventilation for the removal of

NOTE

water and fuel vapor from the engine is accomplished by

Refer to the, appropriate technical

the crankcase breather system. The combination

manuals listed in Appendix A for a de-

breather and pressurizing valve is located on the left

tailed description of the engine starter

hand valve cover. During normal operation with valve in

and alternator.

the open position, crankcase ventilation is atmospheric.

For the deep water fording operation, valve is closed

e. Engine Internal Components (fig. 13).

manually to pressurize the engine crankcase.

(1) Cylinder block with bearing cap assemblies. The

d. Engine External Components.

cylinder block with bearing cap assemblies which serve

(1) Oil filler assembly and oil level gage. The oil filler

as a crankcase, is a cast iron alloy. Wet-type cylinder

cap is mounted on top of the left hand cylinder head

sleeves are installed in the cylinder block. Lubricating oil

cover. The oil level gage is mounted on the front left of

passage ways extend the full length of the block and

the engine oil pan.

supply oil to cylinder heads, crankshaft, and rocker

(2) Sending units. A sending unit mounted on the

levels.

(2) Oil pan. The engine oil pan is cast aluminum and

engine oil cooler transmits engine oil pressure to the oil

pressure gage on the vehicle instrument panel. A

contains a deep sump for 60% angularity operation. A

sending unit mounted to the thermostat housing

scavenge intake oil line attached to the double acting oil

transmits the coolant temperature to the water

pump (located at the flywheel end of the oil pan) extends

temperature gage on the vehicle instrument panel.

into the front sump, providing an intake for supplying the

(3) Water pump with pulley assembly. The impeller

necessary oil for lubrication.

(3) Crankshaft. The crankshaft, is a steel forging

type water pump with pulley assembly, mounted on the

front of the cylinder head, is driven from the crankshaft

with four integrally forged counterweights, five main

pulley assembly by one fan belt. The pump circulates

bearing journals, and four connecting rod bearing

water from the bottom of the radiator through the engine

journals. The crank throws are forged in two planes 180

cooling system. The coolant fan is of the pull-type and

degrees apart, with two throws in each plane. Cylinder

mounted to the idler pulley which is driven by the

block oil drain passages provide lubrication to the

crankshaft pulley.

crankcase main bearing. Holes drilled diagonally through

(4) Water temperature thermostat. The water

the crankshaft and connecting rod bearing journals

thermostat is installed in a housing on the front of the

provide direct passages for pressure lubrication of

right cylinder head. Water leaving this housing goes to

connecting rod bearings. The crankshaft is statically and

the radiator expansion tank. The thermostat operates

dynamically balanced.

(4) Crankshaft bearings and crankshaft thrust

from 173 degrees to 186 degrees Fahrenheit. A

thermostat by-pass line allows a limited circulation of

bearings. The five bearings supporting the crankshaft

coolant when the thermostat is closed.

are steel-backed, copper-lead, insert type, split on the

(5) Exhaust manifolds. The exhaust manifolds

diameter so that each bearing half is interchangeable. A

installed on the right and left side of the engine, collect

small tang at the joint positions the bearings in the

exhaust gases from the eight cylinders and route it to two

cylinder block and bearing caps. Holes in the bearings

exhaust pipe and muffler combinations located on each

are alined with the oil passages in the cylinder block.

side of the vehicle.

Grooves in the bearing surfaces aline with the drilled

(6) Intake Manifold Heater. To aid in starting the

holes in the crankshaft bearing journals to provide a

engine when the ambient temperature is 10 degrees

route for oil flow to connecting rod journals. Four

Fahrenheit or below, an intake air preheater is used. The

crankshaft thrust half-rings (bearings) are mounted on

preheater equipment con-

both sides of the rear main

1-4