Bearing Clearance Measuring Procedures; Micrometer Method For Crankshaft Bearings - Volvo Penta 5.0 GL Manual

Bearing Clearance Measuring
Procedures
Micrometer Method for Crank-
shaft Bearings
VPA 7748089 English 09-2007
Inspect the crankshaft bearings for improper seating indicated
14.
by bright, polished sections of the crankshaft bearings.
• If the lower half of the crankshaft bearing is worn or dam-
aged, both the upper and lower halves of the crankshaft
bearing should be replaced.
• Generally, if the lower half of the crankshaft bearing is suit-
able for use, the upper half of the crankshaft bearing should
also be suitable for use.
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The crankshaft bearings are of the precision insert type and do not
use shims for adjustment. If the clearances are excessive, then new
upper and lower crankshaft bearings will be required. The service
crankshaft bearings are available in the standard size and an under-
size.
The selective fitting of the crankshaft bearings are necessary in pro-
duction in order to obtain close tolerances. For this reason, in one
journal bore you may use one-half of a standard crankshaft bearing
with one-half of an undersize crankshaft bearing
NOTICE! Do not use the plastic gauge method to measure con-
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necting rod bearing clearances. The plastic gauge
method for measuring connecting rod bearing clear-
ances will result in unreliable measurements. Use
only the micrometer method to correctly determine
the connecting rod bearing clearances.
In order to determine the correct replacement crankshaft bearing
size, the crankshaft bearing clearance must be measured accurate-
ly. Either the micrometer or plastic gauge method may be used; how-
ever, the micrometer method gives more reliable results and is
preferred.
Measure the crankshaft journal diameter with a micrometer in
1.
several places, approximately 90 degrees apart, and then aver-
age the measurements.
Determine the taper and the out-of-round of the crankshaft jour-
2.
nal. See Engine Specifications 5.0 Litre on page 139.
Install the crankshaft bearings into the engine block.
3.
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Engine — 5.0 & 5.7 Litre
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