Operation
and
Maintenance
Manual
for
WP2.1C/WP3.9C
Series
Marine
Diesel
11
bearing cover bolts, tighten the middle ones first and then the ones on both sides
symmetrically to complete one operation step. The specified torque should be reached
gradually in 2
～
3 steps.
The two halves of main bearings are different. The upper one has an oil groove and an
oil hole. It should be placed in the bearing saddle of the cylinder block. On both sides
of the fifth main bearing cover are installed two thrust bearings to control the endwise
movement of the crankshaft. The thrust bearings
should be placed with the grooved face
outward.The cylinder liner is of the dry type.
After the liners are pressed into the cylinder block,
the top surface of each cylinder liner collar should
be 0.04
～
0.12 mm higher above the surface of the
cylinder block (see Fig.4). For the same cylinder
block, the difference in the height between one
cylinder liner and another should be less than 0.05
mm. If this dimensional tolerance is exceeded,
replace the wrong cylinder liners with selected
ones. When pressing-in a liner, be sure to apply
the force evenly and perpendicularly on its top.
There is a graphite-coated gasket between the cylinder block and cylinder head.
Check to see that the holes in the gasket line up respectively with the holes for the
locating sleeves and the holes for the circulation of water and oil in the cylinder block.
Place an O-ring seal (6.3×18) in the oil hole of the gasket.
3.3 Valve System
Both camshaft gear (part 1 in Fig.4) and injection pump gear (part 3 in Fig.4) are
driven by the crankshaft gear (part 6 in Fig.4) via an idle gear (part 2 in Fig.4). The
gears have dot marks on them . In assembly, all the marks should be correctly placed
to ensure correct valve timing and injection timing (see Fig.5) .
The valves are opened and closed in certain timing events. They are driven by the
camshaft through tappets, push rods and rocker arms.
Fig. 4
