Westerbeke 8.0KW-60Hz Service Manual page 34

ENGINE-DISASSEMBLY, INSPECTION AND ASSEMBLY
;o.....,~;::::-SCALE
PLASTIGAUGE
1. Wipe
all
oil off the crankshaft journal and the bearings
inside surfaces.
2. Install the crankshaft.
3. Cut the plastic gauge such that its length matches the
width of the bearing, then place it on the journal along
the journals axis.
4. Gently fit the crankshaft bearing cap and tighten the bolts
to the specified torque.
S. Remove the bolts and gently remove the crankshaft
bearing cap.
6. Using the scale printed on the plastic gauge bag, measure
the plastic gauges crushed section at its widest point.
STANDARD VALUE 0.02· 0.04mm (.000788· .00157In)
LIMIT O.lmm (.00394In)
FILLET·ROLLED SECTION
NOTE:
The crankshaft pins and journals are fillet-rolled
and must not be machined to undersize dimensions.
CYLINDER BLOCK
1. Visually check for cracks, rust and corrosion and inspect
the cylinder block using a flaw detecting agent. Rectify
defects where possible or replace the cylinder block.
2. Ensure that the top surface is free of gasket chips and
other foreign material. Check the cylinder blocks top
surface for distortion using a straight edge and thickness
gauge.
STANDARD VALUE 0.05mm (.00197;n)
LIMIT O.lmm (.00394In)
MEASURE IN ALL
OIRECTIONS
STRAIGHTEDGE
3. Check the cylinder walls for cracks and seizure marks.
If
defects are evident, bore all the cylinders to oversize or
replace the cylinder block.
4. Using a cylinder gauge, measure each cylinders bore and
cylindricity. If any cylinder is severely worn, bore all the
cylinders to oversize and replace the piston and piston
rings accordingly. Take measurements at the points
shown.
STANDARD VALUE:
CYLINDER BORE 75.5mm (2.97In)
CYLINDRICITY O.lmm or Ie .. (.00394In)
MEASURE
CYLINDER
GAUGE
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BORING CYLINDERS
1. Oversize pistons to be used should be determined on the
basis of the cylinder with the largest bore.
2. Oversize pistons are available with the following oversize
dimensions: 'O.25mm, O.5Omm, O.75mm and l.OOmm.
Measure the diameter of the piston to be used. Boring
must be carried out such that the piston-to-cylinder
clearance complies with the standard value. The pistons
diameter should be measured at the points shown.
3. Calculate the boring finish dimension based on the piston
diameter dimension.
BORING FINISH DIMENSIDN
=
PISTON O.D. + PISTDN-TO-CYLINDER
CLEARANCE (0.02 - O.04mm (.000788 •• 00157In)) - HONING MARGIN
(0.02MM)
4. Bore each cylinder to the calculated boring finish
dimension.
A
CAUTION:
To prevent distortion caused by
heat increased during boring, bore the cyllnden; in
the following order: No.2, No.4, No.1 and No.3.
S. Hone the cylinders to the final finish dimension (piston
0.0. + piston-to-cylinder clearance).
6. Check the clearance between the pistons and cylinders.
STANDARD VALUE 0.02 • 0.04mm (.000788 - .00157In)
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THRUST OIRECTION
~ WESTERBEKE
PISTON D.D.
Engines & Generators
26