C-57
35 Series 4WD, Model - 3535, 4035, 4535 and 5035 SM June’08
A. DESCRIPTION :
The engine block is the main body of the engine, around
which the engine is built. It is a one piece casting and
webs integral with it form the upper halves of the main
bearing supports. The lower half bearing supports are
in the form of caps machined to mate with the webs
in the crankcase. On the upper face of the crankcase
are replaceable heli-coil thread inserts for the cylinder
head capscrews. These inserts are manufactured from
stainless steel which will not rust or corrode. Through
accuracy in manufacture, frictional loss between the
capscrew thread and the insert is reduced, resulting
in an increased clamping pressure on the cylinder head
gasket for a given torque on the bolts.
The crankshaft is supported in 5 main bearings for
4 cylinder engine with end thrust on the rear and for
3 cylinder engine it is supported in 4 main bearings.
The bearings are of the steel backed insert type and
do not require fitting on assembly. The bearing caps,
which hold the lower bearing inserts in position, are
not interchangeable and each one is stamped with its
location in the crankcase No.1 is at the front. The caps
are secured to the crankcase by capscrews and lockwires
in early models and by “Place” bolts, which do not
require any locking mechanisms, in later models.
During manufacture main bearing caps are rough
machined, then assembled to the crankcase prior to
being line reamed. This results in each bearing cap being
fitted for only one position, therefore, finished bearing
caps cannot be supplied individually for service due to
the necessity for line reaming to fit the particular bore
where it is intended to mate.
The crankshaft supports the connecting rods and pistons
along its length and converts the reciprocating
movement of the pistons into the rotary movement
required to drive the transmission. At the front end of
the crankshaft is the gear which drives the timing gear
train and the pulley which drives the fan and water
pump. The flywheel is mounted on the rear of the
crankshaft and to this is mounted the clutch which
forms the link between the engine and transmission.
The purpose of the flywheel is to oppose and moderate,
by its inertia, any fluctuation in the speed of the engine.
It counteracts varying torques during the stroke of the
engine and provides a rotating balance weight which
carries the crankshaft over dead centres. The flywheel
is secured to the crankshaft by six capscrews with
locking plates. Dowels are provided in the crankshaft
flange for accurate location. The starting ring gear is
a shrink fit on the flywheel and is replaceable.
Extreme care must be taken to assure
perfect cleanliness of the crankcase, crankshaft and
bearings after service has been completed.
Crankcase, Crankshaft, Main Bearings & Flywheel
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