Bearing Selection

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Measure bearing clearance to determine the correct replacement bearing insert size. There are two methods to measure bearing clearance.
- Method A gives more reliable results and is preferred. Method A yields measurement from which the bearing clearance can be computed.
- Method B yields the bearing clearance directly. Method B does not give any indication of bearing run-out.
IMPORTANT: Do not mix inserts of different nominal size in the same bearing bore.
To measure bearing clearance using Method A, use the following procedure:
1. 2.1 Measure crankshaft bearing journal diameter with a micrometer in several places, 90° apart. Average the measurements.
2. 2.2 Measure crankshaft bearing journal taper and runout.
3. 2.3 Install inserts and lower crankcase. Tighten bearing cap bolts to specification.
4. 2.4 Measure bearing I.D. in several places 90° apart, average measurements.
5. 2.5 Subtract journal measurement from bearing I.D. measurement to determine clearance.
6. 2.6 Determine whether clearance is within spec. If out of spec choose different inserts.
7. 2.7 Measure connecting rod inside diameter in same direction as the length of rod with an inside micrometer.
  
  Fig 1: Measuring Crankshaft Bearing Clearance (Method A)
  Courtesy of GENERAL MOTORS CORP.
8. 2.8 Measure crankshaft main bearing inside diameter with an inside micrometer.
9. 2.9 Select a set of bearing inserts that will produce desired clearance.
10. 2.10 If specified clearances cannot be met, the crankshaft journals must be reconditioned and undersized bearing inserts installed.
To measure bearing clearance using Method B, use the following procedure:
1. 3.1 Clean used bearing inserts.
2. 3.2 Install used bearing inserts.
3. 3.3 Place a piece of bearing gaging plastic across the entire bearing width.
4. 3.4 Install bearing caps.
  NOTE: In order to prevent the possibility of cylinder block or crankshaft bearing cap damage, the crankshaft bearing caps are tapped into the cylinder block cavity using a brass, lead, or a leather mallet before the attaching bolts are installed. Do not use attaching bolts to pull the crankshaft bearing caps into the seats. Failure to use this process may damage a cylinder block or a bearing cap.
5. 3.5 Install the bearing cap bolts.
  IMPORTANT: Do not rotate the crankshaft.
6. 3.6 Remove bearing cap, leaving the bearing gaging plastic in place. It does not matter whether bearing gaging plastic adheres to the journal or to the bearing cap.
7. 3.7 Measure bearing gaging plastic at its widest point with the scale printed on the gaging plastic package.
8. 3.8 Remove gaging plastic.
9. 3.9 Select a set of bearing inserts that will produce the desired clearance.
  
  Fig 2: Measure Bearing Clearance (Method B)
  Courtesy of GENERAL MOTORS CORP.