TM 5-3895-382-24
The pistons have two compression rings and an oil control ring.
The groove for the top ring has a hard metal insert in order to
reduce wear of the groove. The skirt has a layer of graphite in
order to reduce wear.
The correct piston height is important in order to ensure that
the piston does not contact the cylinder head. The correct
piston height also ensures the efficient combustion of fuel
which is necessary in order to conform to requirements for
emissions.
A piston and connecting rod are matched to each cylinder.
The piston height is controlled by the length of the connecting
rod. Seven different lengths of connecting rods are available in
order to attain the correct piston height. The different lengths
of connecting rods are made by machining the small end
bearing off-center in order to form an eccentric bearing. The
amount of the eccentricity of the bearing creates the different
lengths of the connecting rods. Two heights of pistons are
available in order to attain the correct piston height. The piston
heights match specific lengths of pistons.
NOTE:
Always refer to the engine identification number
in order to get the correct new parts.
The crankshaft has five main journals. End play is controlled
by thrust washers which are located on both sides of the center
main bearing.
The timing case is made of aluminum. The timing gears are
stamped with timing marks in order to ensure the correct
assembly of the gears. When the number 1 piston is at the top
center position on the compression stroke, the marked teeth of
the following components will match the marks that are on the
idler gear crankshaft, camshaft and fuel Injection pump. There
is no timing mark on the rear face of the timing case.
The crankshaft gear turns the idler gear which then turns the
following gears:
the camshaft gear
the fuel injection pump
a lower idler gear which turns the gear of the lubricating
oil pump
The camshaft and the fuel injection pump run at half the rpm of
the crankshaft.
The cylinder block provides support for the full length of the dry
cylinder liners. The cylinder liners are a press fitted part. The
cylinder liners are pressed into the cylinder block. The cylinder
liners have a flame ring above the flange.
Either a Lucas DP 200 Series fuel injection pump is installed
on the engine, or a Stanadyne fuel injection pump is installed
on the engine. Both pumps conform to requirements for
emissions. Both the pump timing and the high idle are preset
at the factory. Adjustments to the pump timing and high idle
should only be made by personnel which have had the correct
training. The fuel injection pumps have mechanical governors
in order to control the engine rpm.
Coolant from the bottom of the radiator passes through the
centrifugal coolant pump. The pump is driven by a gear. The
gear of the pump is driven by the gear of the fuel injection
pump.
If equipped, an air compressor is located on the left side of the
engine. The air compressor is mounted directly to the rear
face of the timing case. The air compressor is driven by the
main idler gear through an idler gear for the compressor. The
cylinder head of the air compressor is cooled by coolant from
the engine. The air compressor is lubricated by the lubrication
system of the engine.
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