THose calibrated dowel rods, pencils, pieces of wire or pinky fingers are notorious for being 20 to 30 degrees out to lunch!
How many degrees of crank rotation are there during dwell time when the piston just gets to tdc and the lag before it starts to go back down?
You need a piston stop.
You need to be accurate or you're wasting your time.
A link for you.
http://www.crankshaftcoalition.com/w...op_dead_center