Greetings all.
I have 71 Ford 302 and want to find top dead center using a piston stop. I am confused on the initial setting of the stop. How do you know how far to adjust the end that contacts the piston?? And do you have to start at the approximate location of TDC?

Thanks

 

TDC is the point where the piston reaches it's highest point in the cylinder before dropping back down. There are two "TDC" points in a 4 stroke engine's cycle, one at the top of the compression stroke, one at the top of the exhaust stroke. You would position the stop just above the point where the piston reaches it's highest point, then adjust it down when the piston gets to that point. You'll need to rotate the crank back and forth to find that point. Also remember that there's a few degrees of dwell time at TDC as the crank throw rotates under the connecting rod.

 

Thanks Baddad. This helps!

 

I always use a degree wheel to find TDC.
Using a stop bolt you can rotate the engine until it hits the bolt. Note the number on the degree wheel. Now remove the bolt rotate the engine past TDC (Approx.) and then reinstall the stop bolt. Now back the engine until it hits the bolt again. Note the number n the wheel. Mark the point on the wheel that is halfway between the two numbers the engine stopped at. That should be TDC.

 

You can use Jim's technique without a degree wheel. Mark the damper at the stop point either side of TDC. The point midway between these points is TDC.