Engine - Roller Lifter Camshafts
88chevy21Number: 88-271-6A
Section: 6A
Date: JUNE, 1988
Subject: ROLLER LIFTER CAMSHAFTS
Model and Year: 1987-88 CAPRICE, CAMARO, CORVETTE WITH 4.3L (VIN CODE Z), 5.0L (VIN CODE E, F, H) AND 5.7L (VIN CODE 8) ENGINES
TO: ALL CHEVROLET DEALERS
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 surface 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.