I have a factory service manual and have been puzzled by the formula on the valve clearance page. I think there may be a typo and I'm wondering if you could clear it up for me. The formulas are S = (V+T) - 20 and S = (V+T) - 25. According to the manual, S = Shim thickness to be used, V = Measured valve clearance, and T = Shim thickness required. Shouldn't T actually be "current shim thickness". The wording has got me confused and your spreadsheet would suggest that T = the thickness of the current shim. Am I right about this?
This spreadsheet would suggest so. It is a great tool by the way.
Valve clearance calculator