The Ford Barn - View Single Post

Bored&Stroked · 10-21-2019, 10:48 AM

RE: Since your going to have to use a dial indicator anyway, to get accurate readings, why not use it to set TDC?

The reason that many advocate for the positive stop method of finding TDC is due to the amount of piston dwell (in crankshaft degrees) at TDC. In other words, there are a few degrees of rotation where the dial indicator doesn't show movement. One could think they are at TDC with the crank actually being in a slightly different position than the dial indicator shows. So, this causes your TDC "pointer" to be off just a bit.

You can always use BOTH methods - so that your cross-validate one against the other . . . to achieve your final pointer setting.

When I use a dial indicator only, I have to visually pay attention to the "before/after" movement of the crank to figure out where TDC is. Hopefully I'm making some sense . . .

10-21-2019, 10:48 AM	#31
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,067	Re: Cam Degreeing/Checking Important RE: Since your going to have to use a dial indicator anyway, to get accurate readings, why not use it to set TDC? The reason that many advocate for the positive stop method of finding TDC is due to the amount of piston dwell (in crankshaft degrees) at TDC. In other words, there are a few degrees of rotation where the dial indicator doesn't show movement. One could think they are at TDC with the crank actually being in a slightly different position than the dial indicator shows. So, this causes your TDC "pointer" to be off just a bit. You can always use BOTH methods - so that your cross-validate one against the other . . . to achieve your final pointer setting. When I use a dial indicator only, I have to visually pay attention to the "before/after" movement of the crank to figure out where TDC is. Hopefully I'm making some sense . . .