Measuring Connecting Rod Bearing Clearance - Gaging Plastic Method

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

IMPORTANT:

Connecting rod bearings are a precision insert type. Connecting rods are of a powdered metal design and cannot be shimmed or filed for bearing fit. If clearances are found to be excessive, a new bearing and/or connecting rod are required.
Do not rotate the crankshaft while gaging plastic is between the crankshaft journal and the bearing surface.

Remove the bearing cap, bearing half and bolts.

Fig 1: View Of Piston, Connecting Rod, Bearing Cap, Bearing Halves & Bolts

Courtesy of GENERAL MOTORS CORP.

Install the gaging plastic onto the connecting rod bearing journal. Install the gaging plastic the full width of the journal.

Fig 2: View Of Gaging Plastic Installed On Crankshaft Journal

Courtesy of GENERAL MOTORS CORP.

Install the bearing cap, bearing, and bolts.
Tighten:
1. Tighten the connecting rod bolts first pass to 20 N.m (15 lb ft).
2. Tighten the connecting rod bolts a final pass to 75 degrees using the J 45059 .
  Refer to Piston, Connecting Rod, and Bearing Installation .

Fig 3: View Of Piston, Connecting Rod, Bearing Cap, Bearing Halves & Bolts

Courtesy of GENERAL MOTORS CORP.

Remove the bearing cap, bearing, and bolts.
Measure the gaging plastic at its widest area using the scale supplied with the plastic gaging kit.
The connecting rod bearing clearance should be 0.023-0.076 mm (0.0009-0.003 in).

Fig 4: Measuring Gaging Plastic

Courtesy of GENERAL MOTORS CORP.