GM: Electra/Park Avenue/Ninety-Eight 1990-1993

Connecting Rod Bearings


If you have already removed the connecting rod and piston assemblies from the engine, follow only Steps 3-7 of the following procedure.


The connecting rod bearings are designed to have a slight projection above the rod and cap faces to insure a positive contact. The bearings can be replaced without removing the rod and piston assemblies from the engine.

  1. Drain the engine oil and remove the oil pan. See the `Oil Pan' removal procedures. It may be necessary to remove the oil pump to provide access to rear connecting rod bearings.
  3. With the connecting rod journal at the bottom of the travel, stamp the cylinder number on the machined surfaces of the connecting rod and cap for identification when installing, then remove the rod nuts and caps.
  5. Inspect journals for roughness and wear. Slight roughness may be removed with a fine grit polishing cloth saturated with engine oil. Burrs may be removed with a fine oil stone by moving the stone on the journal circumference. Do not move the stone back and forth across the journal. If the journals are scored or ridged, the crankshaft must be reconditioned or replaced.
  7. The connecting rod journals should be checked for out-of-round and correct size with a micrometer.

Crankshaft rod journals will normally be standard size. If any undersized bearings are used, all will be 0.254mm undersize and 0.254mm will be stamped on the number 4 counterweight.

If plastigage® material is to be used:

  1. Clean oil from the journal bearing cap, connecting rod and outer and inner surfaces of the bearing inserts. Position the insert so that the tang is properly aligned with the notch in the rod and cap.
  3. Place a piece of Plastigage® material in the center of lower bearing shell as shown in the illustration.
  5. Install the bearing cap onto the connecting rod and torque to specifications. Remove the bearing cap and determine the bearing clearances by comparing the width of the flattened plastic gauging material at its widest point with the graduation on the Plastigage® package. The number within the graduation on the envelope indicates the clearance in thousandths of an inch or millimeters. If this clearance is excessive, replace the bearing and recheck the clearance with the Plastigage® material. Lubricate the bearing with Assembly Lube or engine oil before installation. Repeat Steps 2-7 on the remaining connecting rod bearings.

All rods must be connected to their journals when rotating the crankshaft, to prevent engine damage.