NOT that this method won't work if you're REALLY, really careful but with the stop being that close to top of piston travel, I think it would be easy to mis-mark the actual stopping point on pulley, because as the piston is near it's upper-most travel in the cylinder, there's a situation where a FEW degrees of crank movement can translate to negligable upward movement of piston. That's why I suggested positive stop at least 3/4" down from top of piston movement. Just FWIW for accuracy. DD