Measuring Wall Thickness of Main and Rod Bearings
 

What I learned today while assembling my LS motor.
Large end of rod is round, but with the bearing insert installed it's not.

The location on the bearing that is measured is acquired important. Crankshaft bearings should be measured 90° to the parting line. By design most crankshaft bearings have an eccentric design, which means the wall thickness at the parting line is not equal to that at the 90° center-line.

The purpose of the eccentric design is to compensate for casting distortion during operation, create a “wedge” affect that promotes the formation of oil film, and for slight tolerance differences of the jointing components. To determine the amount of eccentricity, measure the bearing at the center-line and then at approximately 3/8” above the parting line since some bearings may also have an additional “relief” near the parting ends.

When using plastic-gauge it should be inline with the rod direction to get a good measurement.