Note: you may actually see this on the 'net: "To find the crankshaft rotational position from the piston's location in the bore, divide the stroke in inches by 180°. This gives you the stroke per degree. Example: 4.00" stroke ÷ 180 = .0222" per degree. Divide the measured piston position down from TDC by .0222" to get the crank angle. In this case, the piston is 1.13" down, so the rotation is 51°.
This is always wrong at every point (except 0° and 180°).
