TM-9-2815-200-35
ENGINE, WITH CONTAINER:TURBOSUPERCHARGED, DIESEL ,FUEL INJECTION ,90-DEGREE “V” TYPE, AIR - COOLED ,12 - CYLINDER , ASSEMBLY ;MODELS AVDS-1790-2M (2815-856-4996), AVDS-1790-2A AND AVDS-1790-2AM (2815-856-9005)
TECHNICAL MANUAL; DIRECT SUPPORT, GENERAL SUPPORT AND DEPOT MAINTENANCE MANUAL INCLUDING REPAIR PARTS AND SPECIAL TOOLS LISTS
TM-9-2815-200-35 - Page 43 of 779
(e) Double lip oil seal in cooling fan drive
for deep-water fording to prevent water from
entering the engine.
(f) An improved fuel injection pump
incorporating a filter at the fuel inlet to prevent
foreign materials from entering the pump,
thereby extending pump life.
(g) Simplified and improved cooling fan
clutch, eliminating the hydraulic engagement
feature.
(h) Oil filler tube has been relocated at
left rear of left turbosupercharger to prevent oil
spillage from plugging cylinder cooling fins and
restricting air flow
through the engine and
transmission oil coolers. The relocation
eliminated the need for the oil filler and indicator
tube splash pan drain.
(i) Primary fuel filter screen type element
has been replaced with a high capacity
replaceable-type element.
(j) Wall thickness of cylinders has been
increased to improve service life. Cylinders with
increased wall thickness can be identified by
machine groove around mounting base flange.
(k) Drain cocks and hoses on fuel filters
were replaced with rigid lines and drain valves
located on top of the engine.
(l) Additional clamps and supports have
been added to fuel injection lines to reduce line
breakage from vibration.
(m) Added numerous tube and hose
clamps and rerouted lines to prevent line failures
from chaffing and vibration.
(n) Added a preformed packing to starter
drive bearing cage, and a flat gasket to the drive
adapter to prevent oil leaks. Preformed packings
cannot be used on engines which have bearing
cages without the groove for the preformed
packing.
(o) Time totalizing meter added to record
total engine operating hours.
1-7. Location of Engine Components
a.
In this manual the terms defined in b
through e, below will be used to identify the
location of parts and assemblies on the engines.
b.
The ends of the engines will be called the
“damper end” or “front” and the “flywheel
end” or “rear”.
c.
As viewed from the front end toward the
rear, the side to the right will be called the “right
side” and the side to the left will be called the
“left side”. Beginning at the front, the right bank
of cylinders is numbered lR through 6R and the
left bank of cylinders is numbered IL through
6L.
d.
Starting from the front, the main bearings
are numbered 1 through 7.
e.
The cylinders, pistons, connecting rods, and
connecting rod bearings are numbered with their
respective cylinder number locations.
1-8. General Description
a.
The Model AVDS-1790-2-M, AVDS-1790-
2-AM and the AVDS-1790-2A engines are 12-
cylinder, 90 degree, V-type, 4-cycle, air-cooled,
turbosupercharged, diesel engines. The cylinder
assemblies are individually replaceable units,
with overhead valves and valve rocker assem-
blies in the head. The cylinders are arranged in
two banks of six cylinders each. Each bank of
cylinders has an overhead camshaft arrangement
to actuate the valves of each cylinder.
b.
The engines feature a fuel injection system
and a turbosupercharged air induction system
which obtains optimum engine performance.
The fuel injection system has a fuel injection
metering pump which supplies metered fuel to
individual
cylinders
through fuel injector
nozzles. The fuel supply pump assembly (figs. 1-
3 and 1-6) located at the front of the engine,
draws fuel through the primary and secondary
fuel systems from the vehicle fuel tanks and
delivers it to the injection pump. A tur-
bosupercharger assembly (figs. 1-1, 1-2, 1-4, and
1-5 ) is located on each side of the engine at the
rear. The turbosuperchargers are exhaust-gas
driven and increase the air flow pressure entering
the air intake manifolds (figs. 1-1, 1-2, 1-4, and
1-5).
c.
The engines are equipped with a 28 volt,
300 amp, dc generator (figs. 1-1 and 1-4) and a
24 volt solenoid operated starter (figs. 1-2 and 1-
5).
d.
The engines are lubricated by a forced feed
system. The system consists of three circuits;
i.e., the scavenge circuit, the main or pressure oil
circuit, and the piston cooling circuit. These
circuits are operated independently by one oil
pump which consists of three separate sections.
e.
The engines are equipped with two intake
manifold heaters (figs. 1-1, 1-2, 1-4, and 1-5)
which are installed in the air intake systems
between the intake manifold elbows and the
turbo superchargers.
The heaters, whe n
operated, preheat the air entering the cylinders
to facilitate cold weather starting and cold
weather idle operation.
1-3
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