2 Answers

Instructions
1
Pull the distributor cap off the engine by unbolting it off. Observe the current rotor position.

2
Take a breaker bar with a socket that will fit on the crankshaft pulley. Put it on the crankshaft damper pulley, making sure it fits.

3
Turn the crankshaft pulley clockwise, slowly. Watch the rotor in the distributor. When the rotor starts moving, stop turning.

4
Mark the damper pulley position with chalk or a marker so you can remember the exact position. The mark should be placed on the crankshaft damper.

5
Turn the crankshaft in the opposite direction carefully and slowly. Pay attention to the rotor in the distributor. Once it begins to move, stop turning immediately.

6
Mark the second crankshaft position again.

7
Measure the number of degrees of rotation of the crankshaft. Wrap a measuring tape around the crankshaft damper where the marks are located to measure the circumference of the damper. Then measure the distance between the two marks made.

8
Divide the distance between the two marks by the total circumference of the damper. Multiply the result by 360, which is the total number of degrees in a circle. The result will the give you the amount of degrees between the two marks.

A chain that isn't loose will have about three to five degrees of reverse motion before the distributor begins to turn. A timing chain that is very loose and needs to be replaced will have 10 or more degrees of reverse motion.

Read more: How to Check a Timing Chain | eHow.com http://www.ehow.com/how_7521157_check-timing-chain.html#ixzz22ubnRSBC

If it's bad, replace it with a "Jackson" gear drive. Cost a few bucks more but well worth it.