Pre assemble or no?

[degreeoff1]

OK...so here I am @ the time of cam towers heads etc etc. Now our wonderful host's book says that I can assemble without the piston/valve check or not. Should I as I am using ross 9.8 to 1 comp and GE40 cams....The entire top end came from a car that was set up this way with 920 miles on it....I am right @ the limit deck height wise, so what are your feelings on this?

(PS I kind of want to do it anyways if only to have a practice run on cam timing....)

Thanks

Josh the novice 9elben engine builder

[KTL]

Check it. You've got the advantage that your piston and cam assembly are known to work together, but how close you don't know. And like you said, it's good education.

You can count the screw turns or actually watch the clearance measurement on your dial indicator. I did not feel comfortable turning the valve in to a set lift amount and then slowly rotating the crank to check for clearance/interference. Seems easy to bend a valve if you're not VERY careful. So instead I rotated the crank to a certain position, and turned in the valve adjustment screw until the valve contacted the piston. I found that my DC20 cams on stock 3.2 pistons would have the tightest clearance at approx. 10 degrees past TDC overlap. Yours will differ with a different cam profile.

[p911sc]

I agree with Kevin. I would check the clearance. Its easy enough to do and it will give you piece of mind. I used the same approach...rotating the engine first and then turning in the adjustment screws while counting the number of turns.
Rick

[304065]

Assemble, then test. If something's not right, you just preassembled!

It's easy enough to clean the sealant off the head-to-cam tower interface.