Roller Lifter Camshafts - Cam Lobe Appearance

88pontiac11

Bulletin Number: 88-6-55
Reference Number: 836118
Publish Date: 6/88
Subject: ROLLER LIFTER CAMSHAFTS


Models 1987-88 FIREBIRD WITH 5.0L (VIN F AND H),
Affected: OR 5.7L (VIN 8) ENGINES
The camshafts currently used in roller lifter engines are made of steel and polished to a fine mat finish. After running the engine for a short period of time, the lifter track (the path the lifter contacts) on the cam lobe burnishes to a smooth mirror finish. This results in a shiny path around the cam lobe which varies in width and is surrounded by areas with a dull off color sufaace finish. This burnishing is a desirable work hardening condition and should not be confused with wear. As a result of this unusual appearance, any decision to replace a roller lifter style camshaft should be based on measuring lift or on the existence of a wear step greater than .005" on the face of the cam lobe. The decision should not be made based on the appearance of the cam lobe surface.

This is an informational bulletin.