How to Change a Grand Prix Timing Chainby Christopher L. Ingersoll
The timing chain is one of the most crucial components of your car's engine. The camshaft, crankshaft, pistons, spark plugs, alternator and valves all have to perform their tasks in the right order at the right time or the engine won't run correctly, or at all. The Grand-Prix models have powerful engines so it is very important that the timing is done accurately or the sheer force of the engine could damage itself. You should have a good knowlege of the Grand-Prix engine and its components before attempting timing chain repair.
Remove the timing chain cover, located on the left side of the engine block when you're looking in from the front, by unscrewing the bolts around the edge of the cover with a socket wrench.
Turn the camshaft sprocket bolts two full rotations to loosen them, but do not remove them completely
Screw in the vibration damper bolt into the end of the crankshaft and turn the crankshaft using a socket wrench on the bolt head until the timing marks on the crankshaft and camshaft sprockets are aligned, or at "Top Dead Center." The specific alignment should be on the timing chain cover or on the sticker you will find under the hood.
Remove the two camshaft sprocket bolts with a socket wrench, taking care not to move the crankshaft -- which is still linked up with the sprocket -- in the process.
Pry the camshaft sprocket off the camshaft with two large screwdrivers and slip the chain off with the sprocket.
Pull the crankshaft sprocket with the puller.
Place the new crankshaft sprocket on the end of the crankshaft. The hole in the sproket should only be able to fit one way on the end of the crankshaft like a key in a lock. Do not bolt it down yet.
Make sure the camshaft is rotated so that the dowel pin, a piece that looks like a metal down poking out of the front of the sprocket, is at 9 o'clock on early models, or 3 o'clock on later models, by turning the sprocket by hand. Check the under hood sticker for specifics as the orientations may change slightly for different years.
Put the chain on the camshaft sprocket and then link it with the crankshaft sprocket.
Make sure that the "O" on the crankshaft is at 12 o'clock and the dowel pin is at the correct position.
Install the two camshaft sprocket bolts in the front of the sprocket and tighten them to 18 foot-pounds of torque if it's a 1989 model or earlier and 21 if it's a 1990 model or later, with a torque wrench. See directions on the torque wrench packaging to make sure that you are holding it correctly or you may get a false reading.
Lubricate the chain and sprockets by pouring minimal amounts of clean engine oil on the chain and sprocket teeth.
Re-install the timing chain cover.
- Make sure to compare the specifications from this article with the sticker on the underside of your car's hood, as specifications are subject to change.
Items you will need
- Vibration damper bolt
- Standard and socket wrench sets
- Screwdriver set
- New timing chain
- New camshaft sprocket
- New crankshaft sprocket
- Engine Oil
- "General Motors, Haynes Repair Manuel"; Robert Maddox, John H. Haynes; 2002
- Aeronautical piston engine image by Andrew Breeden from Fotolia.com