Quote:
Originally Posted by Joe's Garage
You will need a helper to do this.
Remove the spark plug from cylinder #1.
Put a big socket and breaker bar (or a really long ratchet) on the crankshaft/balancer retaining bolt.
Turn the crankshaft clockwise (when viewed from the front) until the timing mark on the balancer starts coming up from below the timing marks/numbers on the timing cover. Try to stop at about 5 or 6 o'clock.
Have your helper hold his/her finger pretty firmly over the spark plug hole for #1. They will feel either suction or pressure at different points as you rotate the crankshaft. That's normal.
Keep rotating the crankshaft clockwise.
As the timing mark on the balancer rotates up, your helper should feel pressure pushing his/her finger off the spark plug hole if the cylinder is on the compression stroke.
There is a 50/50 chance this will happen the first time you come up on the marks. If there is no pressure, cylinder #1 is on the exhaust stroke. Rotate the crankshaft one complete rotation and do it again.
If you visualize the harmonic balancer as a clock, with the timing marks at about 10 o'clock, the pressure should start at around 5 o'clock as you rotate the crankshaft.
You may have to repeat this a couple times to make sure you're on the compression stroke.
When you are on the compression stroke for #1, the pressure should build up just until you get to the 0* timing mark on the timing cover. As you pass 0*, the pressure should change to suction and pull your helper's finger against the hole.
This does not mean that the pressure instantly changes to suction. Work the crankshaft up to the 0* mark and pause until the pressure bleeds off. Then keep turning the crankshaft clockwise and see if any more pressure builds up.
If the pressure continues to build after you pass the 0* mark and then starts sucking in approximately the area where you are now seeing the timing mark when the engine is running, the harmonic balancer is bad and the outer ring has slipped.
Hopefully my explanation is not too confusing......
If you're not sure your timing light is functioning right, you may want to borrow a known good light and verify. Or put your light on a known, correctly timed engine and see what is indicated.
Good luck!
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Thanks. Am familiar with this and similar procedures. I plan to pull the valve cover and verify compression stroke.