Checking
the
crankshaft for
wear.
To check the
crankpins and main journals
for
tapering wear and
out-of-round wear, the diameter
of
each crankpin
or
main journal should be measured at
two
places along
the crankpin
or
main journal, in
two
directions
"A"
and
"B"
each place, as shown in the figure at right. If
necessary, regrind the crankpins and main journals
to
the next under size.
If
any crankpin
or
main journal
has been worn out beyond the service limit, replace
the crankshaft.
Diameter of crankpin
and
main journal
(mm)
Description
Standard
Service limit
Main
journal
43
-0.70
dia.
Crankpin dia.
40
-0.70
Inspection
of
the crankshaft oil clearance. Oil
clearance
is calculated
by
subtracting the diameter
of
main journal
or
crankpin from the inside diameter of
the main bearing
or
rod bearing. To check the main
bearings and rod bearings
for
tapering wear and out-
of-round wear, the inside diameter
of
each main bear-
ing
or
rod bearing should be measured, after its
bearing cap is fastened
to
the specified torque, at
two
places along the bearing, and in
two
directions
"A"
and
"B",
each place as shown in the figure at right. If
necessary, replace the worn bearing with a new one.
If the oil clearance still exceeds the service limit,
regrind the crankshaft
to
the next under size and
replace the bearing with one
of
the corresponding
under sizes.
CAUTION
Checking
Crankshaft
for
Wear
Under·size diameters
(mm)
Description Main
journal Crankpin
0.25
US
42.715""'42.730
39.
715""'39.
730
0.50
US
42.465""'42.480
39.465""'39.480
2
Measuring Main Bearing 1.0.
A crankshaft which has been sized cannot be reground
to
any under size.
Tightening torque
(kgm)
Oil
clearance
(mm)
Description
Standard Description
Service limit
Main bearing
cap
bolt
5.0""'5.5
Main bearing
0.10
Rod
bearing
cap
nut
3.2""'3.5
Rod
bearing
O.
15
Westerbeke
Engines
52
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