I installed my solid roller, and noticed I now have no piston to valve clearance on the intake at maximum lift, and only about .030 on the exhaust. The lift of this cam is about .650, and when you take out the lash, .024, I was sure I wouldnt have a problem. My last cam (flat tappet) was a .610 lift, and I had about .110 clearance at max. lift w/ that. So is that why the cam shop told me to check my pushrod length? I have two length checkers. I assume the procedure is to get to the max. lift, and adjust the pushrod to get the clearance I need, then check the geometry? Someone let me know if Im on the right track with this. Thanks, John

I'm pretty sure that pushrod length isn't going to effect how much lift you get. It effects the placement of the rocker tip on the valve stem.

I know factory roller cams use shorter pushrods by about .8.

You need proper pushrod length to make sure your rocker arm stays in the center of the valve stem or it can slip off among other things.

Here is a link that tells how it's done. I used the rockers that I put in the motor to check mine. http://www.holley.com/HiOctn/TechServ/TechInfo/IECVTTech1.html

Originally posted by Johnny O:
I installed my solid roller, and noticed I now have no piston to valve clearance on the intake at maximum lift, and only about .030 on the exhaust. The lift of this cam is about .650, and when you take out the lash, .024, I was sure I wouldnt have a problem. My last cam (flat tappet) was a .610 lift, and I had about .110 clearance at max. lift w/ that. So is that why the cam shop told me to check my pushrod length? I have two length checkers. I assume the procedure is to get to the max. lift, and adjust the pushrod to get the clearance I need, then check the geometry? Someone let me know if Im on the right track with this. Thanks, John =
John,
Max lift has nothing to do with piston to valve clearance.
The valves get closest on overlap with the exhaust getting the closest just before TDC & the Intake just after TDC.
Lift is not near as important as duration & lobe separation along with where the cam is installed (intake centerline)
If you retard the cam the exhaust valve gets closer & the intake if you advance it.

You adjust pushrod length to get the narrowest pattern on the valve tip as close to center as possible.
Normally you will have the best geometry with the tip of the rocker just to the intake side of center with the valve closed.
Also, the pushrod length will be close to the same as a standard solid depending on what lifter you are using but any time you change cams you need to check it.

Thanks very much guys, and I was tired last night when I did the measurements. I did it wrong, and now after reading here and my "big book", I know what I did. Im going now to measure clearance with the dial indicator method, and Im hoping for the best.