FBIII

I'm putting S4 heads on an S3 shortblock and need to check valve to piston clearance. Is it possible to position the cams at a point where they will run nearest to the piston or do I have to reassemble the chest and put a timing belt on and run thru a complete revolution?

toofast928

"have to reassemble the chest and put a timing belt on and run thru a complete revolution"

Yes it's the only way to do it.

123quattro

What exactly are you trying to figure out? If you want to know relative valve to piston clearance, you will need to reassemble and put some putty on top of the piston and then spin it. Then you take it back apart and measure the impression.

You can't just put the valve at their lowest point and measure the distance to the piston at it's highest point because the two parts will be occupying the same space.

FBIII

I thought it might be possible to statically position the piston and camshafts to mirror the moment that they run closest to one another.

123quattro

If you had complete cam profile data, you could simulate it in excel or something with the motion equations. I doubt you can come up with enough cam data though.