Checking The Cylinder Block - Westerbeke 9.0 BCG Technical Manual

Checking the Cylinder Block
1. Check the cylinder block for damage or cracks. If neces-
sary, repair or replace the cylinder block.
2. Check to see that the oil passages and coolant passages
of the cylinder block are open. If clogged, remove with
compressed air or a wire probe.
3. Check the cylinder block for distortion. If it exceeds the
allowable limit of distortion, repair or replace the cylinder
block.
Allowable Limit of Distortion: 0.002 inches
(0.05 mm)
2
4. Check for scratches or burns on the cylinder walls. If necessary, repair by boring each cylinder or replace
the cylinder block.
5. Measure the wear on the cylinder bores at
the six positions shown in the figure to the
right with an inside micrometer. (The wear
is the difference between the maximum and
minimum diameters.) If the cylinder bores
have worn beyond the specified wear limit,
the cylinder block requires boring to restore
each cylinder's true wall surface.
Standard Bore Diameter: 2.9921 - 2.9933
inches (76.00 - 76.03 mm)
Out-of-Roundness, Taper Limit: 0.0031 in-
ches (0.08 mm)
Wear limit: 0.0039 inches (0.10 mm)
6. Check the ridge in the cylinder. If the engine
has a large number of hours on it, a large
cylinder ridge most likely will be present. If
a ridge exists, have the cylinders reamed to
remove these ridges. Leaving these ridges
in the cylinder can break piston rings when
the pistons are installed in the engine. In ad-
dition, if new piston rings are to be installed,
have the cylinder walls deglazed (roughed
up) so the rings may seat properly.
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