Clearance

In order to determine the correct replacement insert size, accurately measure the bearing clearance. Use either of the following methods to measure the bearing clearance however, the first method gives more reliable results than the second method.
1. This method yields measurements from which to compute the bearing clearance.
a. Measure the crankshaft journal diameter, in several places, approximately 90 apart.
b. Average the crankshaft journal diameter measurements.
c. Measure the taper and runout.
d. With the bearing inserts installed in the correct bore and torqued to specification, measure the bearing insert ID with an inside micrometer.
e. If new inserts are replacing the inserts, measure after installing the new inserts.
f. Select a suitable set of inserts, if the readings are within limits.
^ Bearing sets are available in standard and undersize, in order to keep clearances within the limits.
^ Replace the crankshaft if the clearances cannot be brought into specifications.
2. This method yields the bearing clearance directly, however it does not give any indication of bearing or journal runout.
a. Install all of the bearing inserts into the block.
b. Install the crankshaft into the block.
c. Place a piece of gauging plastic across the entire bearing width.
d. Seat the bearing cap carefully, by tapping it lightly with a suitable tool.

CAUTION: Do not rotate the crankshaft.

e. Torque the bearing cap bolts to specification.
f. Remove the bearing cap, leaving the gauging plastic in place, regardless of whether the gauging plastic adheres to the journal or to the bearing cap.
g. Measure the flattened gauging plastic, at its widest point, with the scale printed on the gauging plastic package.
h. Remove all traces of the gauging plastic after measuring.