Camshaft Drive System

WARNING: This page is about a different car, the 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The camshaft drive system consists of one primary timing drive chain driven by the crankshaft sprocket. The primary timing drive chain drives 2 intermediate drive shaft sprockets. Each oil pressure fed intermediate drive shaft sprocket drives separate secondary timing drive chains. Each secondary timing drive chain drives the respective cylinder head's intake and exhaust camshaft position actuators.

The primary timing drive chain uses 2 stationary timing drive chain guides and an oil pressure hydraulically actuated tensioner with built-in shoe. The tensioners minimizes timing drive chain noise and provides accurate valve action by keeping slack out of the timing drive chains and continuously adjusting for timing drive chain wear. The tensioners incorporate a plunger that adjusts out with wear allowing only a minimal amount of backlash. The tensioners are equipped with oiling jets to spray oil onto the timing components during engine operation. The secondary timing drive chains use a stationary timing drive chain guide and movable timing drive chain shoe. The secondary timing drive chain shoe is under tension from an oil pressure hydraulically actuated tensioner. All tensioners are sealed to the head or block using a rubber coated steel gasket. The gasket traps an adequate oil reserve to ensure quiet start-up.

There are 2 primary timing drive systems. The first design primary timing drive chain uses a roller timing drive chain and a crankshaft sprocket with roller timing drive chain teeth and incorporates a molded-rubber cushion ring. The second design primary timing drive chain uses an (IT) inverted tooth timing drive chain and a crankshaft sprocket with IT timing drive chain teeth without a molded-rubber cushion ring. The primary timing drive chain connects the crankshaft sprocket with the left and right side intermediate drive shaft sprockets.

The first design intermediate drive shaft sprockets incorporate roller timing drive chain inner and outer sprocket teeth. The second design intermediate drive shaft sprockets incorporate IT primary timing drive chain sprocket teeth and roller timing drive chain secondary timing drive chain sprocket teeth.

The 2 timing drive systems individual components are not interchangeable, do not mix primary roller timing drive chain components with primary IT timing drive chain components.