Piston to valve clearance

[fordteacherguy]

I check valve drop (P/V clearance) in approximately the same range as the other posters but also set up a handy spread sheet that takes those valve drop reading readings and also contains my theoretical valve lifts at those designated points. My spreadsheet calculates P/V clearances by doing the simple adding and subtracting and giving me a total P/V clearance. I also set up some conditional values in Excel that turn the cells red if I'm below a minimum P/V threshold. I've found building a P/V spreadsheet useful because I can move the cam degree cells left or right (simulating advancing or retarding the cam) and see what the new P/V clearance should be with the cam at those various places. Using a P/V spreadsheet also allows me to check a different cam in a bare block with a crank, get the lift @ degree numbers off of that new cam, punch the numbers in to my existing motor valve drop measurement sheet and recalculate new clearances.

As always, you DO need to physically check P/V clearance that math=actual clearance but so far it has worked great for me.