Measure the 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.
Method A
- 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 using J 45059 . See «Special Tools»(ref-239708-S25923693292006080100000) .
- 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.
Method B
- Clean the used bearing inserts.
- Install the used bearing inserts.
- Place a piece of gaging plastic across the entire bearing width.
- Install the 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.
- Install the bearing cap bolts to specification using J 45059 . See «Special Tools»(ref-239708-S25923693292006080100000) .
- Remove the bearing cap, leaving the gaging plastic in place. It does not matter whether the gaging plastic adheres to the journal or to the bearing cap.
- Measure the gaging plastic at its widest point with the scale printed on the gaging plastic package.
- Remove the gaging plastic.
- Select a set of bearing inserts that will produce the desired clearance.