Valve Adjustment - Quick Question

bdholsin

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When adjusting the valves on my '83 Special, is it critical to get the timing mark at exactly top dead center or is it ok to be off by a couple widths of the timing mark? Here's what I'm doing and it's driving me nuts:
1. Remove both spark plugs.
2. Remove the stator cover.
3. Remove the tappet covers.
4. While watching the intake valve on one side I sloooooooowly rotate the engine with a ratchet.
5. Just before TDC the engine rotates quickly just past TDC (that is the part that kills me). The end result is the timing mark being just a couple millimeters past TDC.
6. Perform valve adjustment and then do it again on the other side.

It takes me several (if not a dozen) attempts to hit TDC exactly perfect. Am I splitting hairs or is it close enough? Just curious about this.

Thanks.
 
it's not critical, you are on the base circle of the cam. Use a wrench and go back a few degrees if you have to. An offset box wrench works good for this.
 
Last edited:
A breaker bar instead of the rachet works too. and yes the pressure from the other valves is what makes the engine turn too far.
 
I always suggest setting it so the correct gauge goes and the next size up does not. Then, once you set that valve, rotate the engine back around and re-check that valve. I found it is usually off. Exhaust opens-piston going up, intake opens-piston going down, when piston comes back, (both valves closed/compression stroke) that's TDC.
 
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