I am moving along with the rebuild of my .060 over 427 and mock up is just about complete. I need to degree the cam and measure piston to valve clearance. I've searched the archives and have a few questions and just need assurance that I am doing this correctly.

To measure piston to valve clearance I am going to follow these steps:

Basic info: Piston is SRP 152149 w/ 29cc dome.
Cam Lunati 402A3 243/276 .586/.600

1. Install light weight checking springs on the head.
2. Install the head and use the actual pushrods, lifters etc...

Question: What valve lash setting do I use? (The lash with cam card is
hot)

Question: Do I need to use the head gasket or can I add the compressed
thickness to my measurement?

3. Rotate the engine to 20* BTDC.
4. Install dial indicator on head and zero it on the retainer.
5. Press valve down until it contacts piston, take measurement, rotate engine
5* measure again; continue this until 20 degrees ABDC.

Question: Does this process look correct?

Bump

L,
I usually use a .030" valve spring shim under each corner instead of a head gasket. Most gaskets are about .038 so that gives you a little breathing room. Lash at the hot spec should be ok. If you want to be real safe, set it at zero.
Now here is where some guys will disagree ..... I always use clay when checking valve to piston clearance. The problem with the method you described with the dial indicator is it does not give you any idea whatsoever if the valve is too close to the edge of the valve cutout. I have seen pistons with the cutouts plenty deep, but not big enough diameter. If the valve is real close to the edge of the cutout, it might chek ok with your method, but as soon as you start the engine and the piston rocks around a little at tdc, you have contact :( Clay will show you how close the valve is all the way around.

Just to add to BillK's ( good ) advise .. I put a light coat of oil on the piston and valve head so the clay wont stick to either. I also prefer to use the actual valve springs that will be used.

They have a pretty informative (and lively) thread going on over at the DRR Tech Talk forum on this subject:

http://drr.infopop.cc/eve/ubb.x/a/tpc/f/80760912/m/9791034221

Thanks guys I don't want to out smart my self on this I just want to be accurate. It looks like I'll go with the clay. Thanks for shim tip Bill!

I use Clay, no head gasket and zero lash. I like to make sure of stuff like that!

Ditto on the "radius" of the valve relief. It can get pretty cozy with 2.19's on a small dome piston.

JIM

We use a procedure pretty close to that detailed by Darin Morgan in the DRR Tech Talk thread referenced above. However, I don't think that is necessary for the typical street/strip ride. But, I do highly recommend getting an old valve, turning it down, "center punching" the reliefs and then checking the radial clearance. This becomes particularly important if you are using aftermarket heads that may have changed the valve placement. It doesn't make much sense to cut the reliefs .030" (as an example) deeper when all you needed to do was offset them a little bit.