964 Cam - Piston to Valve Clearance?

[kstylianos]

By any chance, has anyone performed (and still have the numbers) the piston to valve clearance procedure on an SC using 964 cams timed at 1.26 with all else stock? I'm assuming stock CIS pistons, stock deck height (.25 shims), stock heads (not flycut). If otherwise, please list variations from stock. Just trying to get an idea.

-TIA

[aigel]

You don't have to do the all out piston to valve clearance check that Wayne describes in detail in the book. Go to the end of the valve to piston clearance check chapter and read about the quick and dirty way to do it. If you did not change anything but the cams, you will be fine by setting the valve adjustment screws ath the respective clearance and turning the engine over carefully. If it does not lock up, you are safe.

There should be more than adequate clearance, going from a SC grind to the 964 grind. The lift increase is almost nothing. Most of it is in the duration, IIRC. Check the cam specs between SC and 964. You can also hit up "camgrinder" with a PM and ask him for specs and verification.

George

[kstylianos]

The quick and dirty way is what I'm planning on doing. I just want to get an idea of the clearances in stock form so I can estimate shimming as .25 have been taken off the heads. Deck/squish apperas to be ok, just scared about the high dome CIS pistons getting too close to the intake valve. I'd like to keep the stock .25 shim in there as with the heads being flycut will raise compression just a little. I think I'll be fine, of course I'll check anyway. Just curious if anyone has any BTDT wisdom.

[Jeff Alton]

I think I had at least 2mm of clearance on my 3.2 with these cams. I also had about .17mm removed from the heads when I had them resurfaced during the rebuild. You should not have to worry.

Jeff