Camshaft Drive System

WARNING: This page is about a different car, the 2002 Oldsmobile Aurora and 2001 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.

The four overhead camshafts are driven by three separate fine pitch chains. The primary drive chain connects the crankshaft with the intermediate shaft and sprocket located directly above the crankshaft behind the engine front cover. Each camshaft drive chain connects the intermediate sprocket with both intake and exhaust cams in the cylinder head. Two camshaft drive chains are used; one for each cylinder head. Each of the chains incorporates a hydraulic tensioner to minimize chain noise and provide accurate valve action by keeping slack out of the chain and continuously adjusting for chain wear. This is accomplished by providing engine oil pressure to each tensioner forcing a nylon pad into mesh with the slack side of the chain. As the chain stretches from wear, a ratchet mechanism inside the tensioner prevents the nylon pad from retracting when the engine is turned off and engine oil pressure ceases.