Degreeing cams with heads on

[Ghoste]

I know the proper way to do it is with the heads off and the couple of times I have degrees a cam, this is the way I've done it.  But am I giving up anything by trying it with the heads on?

[greenpigs]

Possible finding the true TDC?

[Ghoste]

That's what I'm asking I guess.  I do have an adjustable positive stop that I've used for other things.  Any reason I can't stick that in the cylinder bring the piston up to it, check the reading on the degree wheel and then rotate the opposite direction and divide the difference to establish TDC or will that be too inaccurate?

[John_Kunkel]

Most of the cams I've degreed in were with the heads installed, as long as you know for sure where TDC is it's no problem.

[Ghoste]

Would it be correct to establish it the way I mentioned or would taking up any slack in the chain by rotating in the opposite direction negate that effort?

[mauve66]

i know people that have feed some nylon rope into the #1 plug hole and then did the full stop one way then the full stop the other then divide by 2, then to verify that it is the #1 stroke and not the #6 stroke they checked the valvestems, i was told they have to BOTH be slightly loose @ TDC,  these people seem to have no problems but again that is 2nd hand info from what they TELL me.

[firefighter3931]

That's what I'm asking I guess.  I do have an adjustable positive stop that I've used for other things.  Any reason I can't stick that in the cylinder bring the piston up to it, check the reading on the degree wheel and then rotate the opposite direction and divide the difference to establish TDC or will that be too inaccurate?

Yep....done it several times and works like a charm. A threaded piston stop in the plug hole does the job ! 


Ron

[Ghoste]

That's exactly what I have Ron.  It threads in there and then another threads into that and has a locknut for when you get it set where you want.