TM 9-4940-549-14&P
ENGINE ASSEMBLY
12-1. GENERAL.
The engine assembly is a six cylinder, four cycle, fuel injected, com-
a.
pression ignition, liquid cooled diesel engine. The assembly consists
of the cylinder head, rocker arm assembly, timing gears and housing,
camshaft, flywheel and flywheel housing, main bearings and crankshaft,
piston and connecting rod assembly, and cylinder block.
The cylinder head is a one piece casting and is detachable. Valve
b.
seats are part of the casting, but valve guides are removable.
c.
The rocker arm assembly is mounted on the cylinder head. It func-
tions to open and close the valves.
d.
The timing gears determine the sequence of valve opening and fuel
.
The gears are enclosed in a housing, the cover of which
Injection.
contains the front crankcase oil seal.
The camshaft actuates the rocker arm assembly which operates the
e.
valves. It is driven by a gear which meshes with the crankshaft
gear.
f.
The flywheel is made of cast iron. The flywheel is attached to the
crankshaft by six bolts, one of which is off center. This permits
the flywheel to be installed in only one position for timing purposes.
The flywheel housing serves as a cover for the rear of the cylinder
block and oil pan and as a partial enclosure for the flywheel. It
provides the mounting for the starter assembly and also contains the
rear crankshaft seal.
The crankshaft has seven main bearing journals and six connecting
g.
rod bearing journals. This arrangement places each connecting rod
journal between two main bearing journals. All bearing journals are
surface hardened and are drilled for oil passages.
The connecting rods are heavy alloy steel forgings with precision
h.
type bearings for the crankshaft and bronze bushings for the full
floating piston pin. The pistons are made of aluminum and are the
solid type (no saw slots or splits in the skirt). Each piston is
fitted with five rings. The top three rings are compression type
and the fourth ring from the top is an oil control ring. The fifth
ring is an oil scraper ring.
i.
The cylinder block and crankcase are cast as a single unit giving
ridged support for the crankshaft. Cooling is obtained by water
jacketing the entire length of the block.
