Location of Engine Components

left bank of cylinders is numbered IL through

(e) Double lip oil seal in cooling fan drive

6L.

for deep-water fording to prevent water from

d. Starting from the front, the main bearings

entering the engine.

are numbered 1 through 7.

(f) An improved fuel injection pump

e. The cylinders, pistons, connecting rods, and

incorporating a filter at the fuel inlet to prevent

connecting rod bearings are numbered with their

foreign materials from entering the pump,

respective cylinder number locations.

thereby extending pump life.

(g) Simplified and improved cooling fan

General Description

1-8.

clutch, eliminating the hydraulic engagement

a. The Model AVDS-1790-2-M, AVDS-1790-

feature.

2-AM and the AVDS-1790-2A engines are 12-

(h) Oil filler tube has been relocated at

cylinder, 90 degree, V-type, 4-cycle, air-cooled,

left rear of left turbosupercharger to prevent oil

turbosupercharged, diesel engines. The cylinder

spillage from plugging cylinder cooling fins and

assemblies are individually replaceable units,

restricting air flow t h r o u g h the engine and

with overhead valves and valve rocker assem-

transmission oil coolers. The relocation

blies in the head. The cylinders are arranged in

eliminated the need for the oil filler and indicator

two banks of six cylinders each. Each bank of

tube splash pan drain.

cylinders has an overhead camshaft arrangement

(i) Primary fuel filter screen type element

to actuate the valves of each cylinder.

has been replaced with a high capacity

b. The engines feature a fuel injection system

replaceable-type element.

and a turbosupercharged air induction system

(j) Wall thickness of cylinders has been

w h i c h obtains optimum engine performance.

increased to improve service life. Cylinders with

The fuel injection system has a fuel injection

increased wall thickness can be identified by

metering pump which supplies metered fuel to

machine groove around mounting base flange.

through fuel injector

individual

cylinders

(k) Drain cocks and hoses on fuel filters

nozzles. The fuel supply pump assembly (figs. 1-

were replaced with rigid lines and drain valves

3 and 1-6) located at the front of the engine,

located on top of the engine.

draws fuel through the primary and secondary

(l) Additional clamps and supports have

fuel systems from the vehicle fuel tanks and

been added to fuel injection lines to reduce line

delivers it to the injection pump. A tur-

breakage from vibration.

bosupercharger assembly (figs. 1-1, 1-2, 1-4, and

(m) Added numerous tube and hose

1-5 ) is located on each side of the engine at the

clamps and rerouted lines to prevent line failures

rear. The turbosuperchargers are exhaust-gas

from chaffing and vibration.

driven and increase the air flow pressure entering

(n) Added a preformed packing to starter

the air intake manifolds (figs. 1-1, 1-2, 1-4, and

drive bearing cage, and a flat gasket to the drive

1-5).

adapter to prevent oil leaks. Preformed packings

c. The engines are equipped with a 28 volt,

cannot be used on engines which have bearing

300 amp, dc generator (figs. 1-1 and 1-4) and a

c a g e s without the groove for the preformed

24 volt solenoid operated starter (figs. 1-2 and 1-

packing.

5).

(o) Time totalizing meter added to record

d. The engines are lubricated by a forced feed

total engine operating hours.

system. The system consists of three circuits;

1-7. Location of Engine Components

i.e., the scavenge circuit, the main or pressure oil

circuit, and the piston cooling circuit. These

a. In this manual the terms defined in b

circuits are operated independently by one oil

through e, below will be used to identify the

pump which consists of three separate sections.

location of parts and assemblies on the engines.

e. The engines are equipped with two intake

b. The ends of the engines will be called the

manifold heaters (figs. 1-1, 1-2, 1-4, and 1-5)

"damper end" or "front" and the "flywheel

which are installed in the air intake systems

end" or "rear".

between the intake manifold elbows and the

c. As viewed from the front end toward the

The heaters, when

t u r b o superchargers.

rear, the side to the right will be called the "right

operated, preheat the air entering the cylinders

side" and the side to the left will be called the

t o facilitate cold weather starting and cold

"left side". Beginning at the front, the right bank

weather idle operation.

of cylinders is numbered lR through 6R and the

1-3