Checking valve shim clearance

Just about to check my valve clearance and was reviewing the spec on my cams
The spec call to set clearance at .020 tappet hight
Not really sure what that means
The Cams are Terry’s WAD .010 intake and Exhaust

Any input is always appreciated


Check the wording again on the clearance setting. A “Special Valve Timing Tappet Clearance” type of statement would refer to how to set the mechanical timing of the cam, which is a separate step from setting tappet clearance for running the engine. 0.020" inches clearance for timing is common.

Hi Roger,
you are correct
Just re read it and it states check intake and exhaust timing @ .20” tappet height
So now I really don’t know how to check timing at that height
I have the motor out for all new gaskets and wanted to check everything while At it
Any insight on how to check


Use a method to find TDC carefully and have a timing degree wheel attached to crankshaft. Then use a dial indicator to look for first opening movement and the last movement just at closure of the valve as the crank rotates the cam.

That part of setting the timing I understand
Where does the .20 come into play


Typically a valve timing event is given at a certain opening dimension. So at .020" opening movement of your intake valve your crank degree wheel should be at 23 degrees btdc.
It’s done that way because that’s when the valve actually starts to flow.
That assumes your lash is set at .010"
That’s what all the serrations are for in the cam gear. Surface a head, block, valve, or seat, chain stretch changes valve timing.
By the way its .020" not .2… big difference.

IIRC, Isky cams gave their specs at 0.050" lift.