TM 5-3895-346-14
GENERAL DESCRIPTION
ENGINE OVERHAUL
GENERAL DESCRIPTION
The two-cycle diesel engines covered in this manual have the same bore and stroke and many of the major
working parts such as injectors, pistons, connecting rods, cylinder liners, and other parts are interchangeable.
The meaning of each digit in the model numbering system is shown in Fig. 2 and 3. The letter L or R indicates
left- or right-hand engine rotation as viewed from the front of the engine. The letter A, B, C, or D designates
the blower and exhaust manifold location on the in-line engines as viewed from the rear of the engine, while the
letter A or C designates the location of the oil cooler and starter on the V-type engines.
Each engine is equipped with an oil cooler, full-flow oil filter, fuel oil strainer and fuel oil filter, an air cleaner,
governor, fan and radiator, and a starting motor.
Full pressure lubrication is supplied to all main, connecting rod and cam- shaft bearings, and to other moving
parts. A rotor-type pump on in-line engines draws oil from the oil pan through a screen and delivers it to the oil
filter. From the filter, the oil flows to the oil cooler and then enters a longitudinal oil gallery in the cylinder block
where the supply divides. Part of the oil goes to the camshaft bearings and up through the rocker arm
assemblies; the remainder of the oil goes to the main bearings and connecting rod bearings via the drilled oil
passages in the crankshaft.
Coolant is circulated through the engine by a centrifugal-type water pump. Heat is removed from the coolant,
which circulates in a closed system, by the radiator. Control of the engine temperature is accomplished by
thermostat(s) which regulates the flow of the coolant within the cooling system.
Fuel is drawn from the supply tank through the fuel strainer by a gear- type fuel pump. It is then forced through
a filter and into the fuel inlet manifold in the cylinder head and to the injectors. Excess fuel is returned to the
supply tank through the fuel outlet manifold and connecting lines. Since the fuel is constantly circulating
through the injectors, it serves to cool the injectors and to carry off any air in the fuel system.
Air for scavenging and combustion is supplied by a blower which pumps air into the engine cylinders via the air
box and cylinder liner ports. All air entering the blower first passes through an air cleaner.
Engine starting is provided by an electric starting system. The electric starting motor is energized by a storage
battery. A battery-charging generator, with a suitable voltage regulator, serves to keep the battery charged.
Engine speed is regulated by a mechanical engine governor.
GENERAL SPECIFICATIONS
4-53
Type ..................................................................
2-cycle
Number of cylinders ...........................................
4
Bore (inches) .....................................................
3.875
Bore (mm) .........................................................
98
Stroke (inches)...................................................
4.5
Stroke (mm) ......................................................
114
Compression ratio (nomi-
nal--(std. engine) ....................................
17:1
Total displacement (cubic
inches) .....................................................
212
Total displacement (litres) .................................
3.48
Number of main bearings...................................
5
48
