Connecting Rod Measurement Procedure

Piston Pin End

1. Courtesy of GENERAL MOTORS COMPANY

   NOTE:

   Measurements of all components should be taken with the components at normal room temperature.

   Measure the piston pin bore to piston pin clearances using the following procedure:

   1. Piston pin (1) bores and pins must be free of varnish or scuffing.
   2. Using an outside micrometer, take 2 measurements of the piston pin (1) in the area of the connecting rod contact.

2. Courtesy of GENERAL MOTORS COMPANY

   Using an inside micrometer, measure the connecting rod (1) piston pin bore.

3. Subtract the piston pin diameter from the piston pin bore.
4. Compare the clearance measurements with the Engine Mechanical Specifications (L84) , or Engine Mechanical Specifications (L87) .
5. If the clearance is excessive, replace the piston pin. If a new pin does not resolve the clearance problem, replace the connecting rod.

Connecting Rod Crankshaft Bearing End

1. Courtesy of GENERAL MOTORS COMPANY

   NOTE:

   Measurements of all components should be taken with the components at normal room temperature.

   Using an inside micrometer, measure the connecting rod (1) crankshaft bearing bore.

2. Compare the bore measurements with the Engine Mechanical Specifications (L84) , or Engine Mechanical Specifications (L87) .
3. Replace the connecting rod if the bore is out of specifications. DO NOT recondition the connecting rod.