Chevrolet 1991 Light Duty Truck Repair Manual page 355

5L engines) difference.
4. Normally main bearing journals wear evenly and
are not out-of-round. However, if a bearing is being
fitted to an out-of-round journal, be sure to fit to
the maximum diameter of the journal. If the bear­
ing is fitted to the minimum diameter and the jour­
nal is excessively out-of-round, interference
between the bearing and the journal will result in
rapid bearing failure.
5. If the bearing clearance is within specifications,
the bearing is satisfactory. If the clearance is not
within specifications, replace the bearing. Always
replace both upper and lower inserts as a unit.
6. A standard or undersize bearing may produce the
proper clearance. Refer to the proper section for
bearing availability. If not, it will be necessary to
regrind the crankshaft journal for use with the next
undersize bearing. Do not grind rolled fillet crank­
shafts, such as used on 2.5L, 2.8L, and 6.2L
engines. After selecting the new bearing, recheck
the clearance.
7. Remove the flattened gaging plastic.
8. Perform the preceding steps on the remaining
main bearings.
GENERAL ENGINE MECHANICAL 6A-19
Figure 38—Measuring the Gaging Plastic
Bearing Journal