Measuring Crankshaft Bearing Clearances (Micrometer Method)
WARNING: This page is about a different car, the 2002 Pontiac Sunfire and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
Measure the bearing clearance to determine the correct replacement bearing insert size. There are two methods to measure bearing clearance.
Micrometer method gives more reliable results and is preferred.
Micrometer method yields measurement from which the bearing clearance can be computed.
Important: Do not mix inserts of different nominal size in the same bearing bore.
- Measure the crankshaft bearing journal diameter with a micrometer in several places, 90 degrees apart. Average the measurements.
- Measure the crankshaft bearing journal taper and runout.
- Install the crankshaft bearing inserts. Tighten the bearing cap bolts to specification.
- Measure the connecting rod inside diameter in the same direction as the length of the rod with an inside micrometer.
- Measure the crankshaft main bearing inside diameter with an inside micrometer.
- Select a set of bearing inserts that will produce the desired clearance.
- If the specified clearances cannot be met, the crankshaft journals must be reconditioned and undersized bearing inserts installed.