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 47 of 779
d.
Forged steel valve rocker arms (A and B )
with roller cam-followers are used. The rollers
are hardened and honed to provide an extremely
smooth and permanent contact surface. Hollow
rocker arm shafts and drilled passages in the
rocker arms convey
1-16. Camshafts
Note.
The key
parentheses refer to
oil to all moving parts.
letters shown below in
figure 1-8.
a.
The left and right camshaft assemblies (C
and K) are mounted, one on each bank, on the
cylinders and operate the valve mechanism. The
camshafts are hollow to provide oil passages for
pressure lubrication to the valve parts and to
permit deflection when the cylinders fire,
Tubular molded rubber hoses enclose the
camshafts between cylinders.
b.
Each camshaft is driven by the accessory
drive gear (M), accessory drive gearshaft
assembly (H), camshaft drive bevel gearshaft
(G), camshaft drive gearshaft (E), and camshaft
driven gear (D) through an inclined quill type
camshaft drive shaft (F). The drive shafts can be
rem oved to permit separate rotation of the
camshafts for engine timing. When camshafts
are correctly’ positioned in relation to the
crankshaft, the drive shafts have different
number of splines on each end and this allows
them to be inserted in the camshaft bevel
gearshafts without disturbing relationship
between camshafts and crankshaft.
1-17. Lubrication System (figs. 1-9 and 1-
10)
a. General.
The main pressure oil pump draws
oil from the pressure oil pump compartment in
the oil pan. This compartment is fed by the
scavenge oil pump which picks up oil from both
ends of the engine oil pan. The pressurized oil is
forced through the engine oil coolers and main
oil filter to the engine oil galleries and bearings.
A pressure regulator valve, located on the right
side of the crankshaft damper and oil filter
housing, is influenced by the pressure in the
main bearing oil gallery and returns the in-
coming excess unfiltered oil to the oil pan. A
small portion of the pressure oil is diverted, after
passing through the main oil filter, and passes
through the auxiliary oil filter to provide the
turbosuperchargers and the fuel injection pump
with oil having a greater degree of filtration. The
piston cooling oil pump picks up oil from the end
compartment (rear) of the oil pan and delivers it
to the piston oil sprayer nozzles. These nozzles
are located in the crankcase, below each
cylinder, and provide a continuous oil spray to
the pistons and cylinder walls.
b. Oil Pan.
The oil pan (figs. 1-1 and 1-4) is a
one-piece, aluminum alloy casting divided into a
pressure oil pump compartment, oil reserve
compartment, and the end compartments at the
front and rear of the pan. The oil pan is designed
to maintain a constant oil level above the main
pressure oil pump pickup tube in the pressure oil
pump compartment during vehicle operation
regardless of the angle at which the engine may
be inclined.
1-7
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