Originally Posted by
LeadSled
finding top dead center by any measures that rely on the height of the piston at TDC, results can vary quite markedly.
That's true. I wasn't gonna mention that, but now that you have, at the top of the stroke, the piston moves very little with fairly large changes in crankshaft angle. It makes it a challenge to figure crankshaft angle accurately, which is what you're really interested in.