Construction
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CONSTRUCTION
General
The Sisudiesel 20/34---series engines (3---, 4---, or 6---cylin-
ders) are water---cooled, four stroke, direct---injection in---line
diesel engines. All engines are produced as naturally aspir-
ated engines, turbocharged engines and the four--- and six
cylinder engines also as intercooled.
The engines have a rigid and ribbed cylinder block. The crank
mechanism is designed for supercharging. The cylinder
liners are wet and supported at the middle. The cylinder head
bolts are high tensile bolts.
Cylinder block
The cylinder block is the main body of the engine, to which
other engine parts are attached. Wet and replaceable cylinder
liners are supported at the middle which reduces vibrations
and directs coolant circulation mainly to the upper part of the
liners.
The seal between the cylinder liner lower part and the cylinder
block is achieved by three o---rings, which are fitted in grooves
in the liner. The upper part is sealed by the cylinder head
gasket.
The camshaft is located in the cylinder block. The camshaft
front bearing location is fitted with a separate bearing sleeve.
The remaining bearing locations are machined directly in the
cylinder block. The latest 620/634---engines have separate
bearing sleeves in all camshaft bearing locations. The drilling
for the camshaft rear end is covered with a plug.
There are spaces on both sides of the rear main bearing for
guide bearing shims (the crankshaft thrust bearings).
Flywheel housing
The flywheel housing is fitted at the rear end of the cylinder
block. The seal for the crankshaft rear end is placed in a bore
in the housing. The starter motor fixing point is fitted in the fly-
wheel housing.
The lower face of the flywheel housing functions as a sealing
surface for the oil sump gasket. This means that the lower face
of the cylinder block must be level with the flywheel housing.
When fitting the flywheel housing, its position is determined
by tension pins.
The flywheel housing are delivered according to the require-
ments set, by the engine application and differet flywheel
housings can be mounted on all engine types.
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