POOR DRIVEABILITY/PERFORMANCE INCORRECT GAS/DIESEL CAMSHAFT

Model and Year: 1981-1986 Caprice and Monte Carlo Models

TO: ALL CHEVROLET DEALERS

Roller lifter camshafts for 1981-85 V8 diesel and 1986 V8 gasoline engines are almost identical except for lobe contour and their fit to the camshaft adaptor. Until recently it was impossible to inadvertently install the wrong camshaft in an engine because:

- The adaptor on a diesel engine is smaller and will not fit a gas camshaft.

- The adaptor on a gas engine contains a pin that must fit into a hole. This hole is not drilled on a diesel camshaft.

Shortly this pin will be removed from the gas adaptor. It would then be possible to inadvertently install a diesel camshaft in a gas engine. This will result in poor performance and economy due to cam lobe contour differences.

Identification:

There is .015" difference between the adaptor hole size. A gasoline adaptor on a diesel camshaft will have a very sloppy fit. The diameter of the camshaft where it fits to the adaptor is:

Gasoline - .951 - .952 Diesel - .936 - .937

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.