I have a new block and some AFR heads and everything. I need to check the piston to valve clearance. I have some clay (from a Cranium game, lol, do I need more high-tech clay?) and I put it on the pistons. How many cylinders should I test? I think I need a lifter that doesn't compress. I have some old hydraulics laying around. How can I jam them so they don't move? I could really use some advice here.

Once it's all assembled, I was thinking I'd turn the crank around one time and then take the heads off to measure the clay. I have calipers and dials, but measuring smushy clay doesn't sound easy. Has anyone here done this before?

 

If you have some old lifters take one apart and remove the spring and place whatever you can get your hands on to put the pushrod cup against the retainer clip in the lifter ,when assembled. (I have used small washers stacked inside).

If you check the one cylender and there is alot or the clearance is really sufficient, then I would check only a few, if the clearance is pretty close then all need to be looked at. Of course I've only done this a few times and each time I did it the clearance was really wide.

 

A few tricks I've used is use light valve springs like an old inner spring. For your hyd lifters I don't know what to tell you, I use solids. I've turned flat hyd. tappets inside out to degree the cam, but it changes your lifter hieght (no cup). I keep an old head gasket for use as a dummy when doing the test, and I only check one cyl., but I do it twice for repeatability. To measure the clay I use a 6 inch machinist's rule, and just plunge it into the part where the valve impresses onto the clay and scrape away part of it, so you can see the edge you just cut, to measure against.

 

I took an old lifter, removed the internals, filled it with some of the "clay" type of epoxy and put the cup back on. You can squish out a little of the epoxy if there's too much in there.

Put a little oil on the clay so it doesn't stick. After cranking it over and removing the head I used a razor blade to slice the clay then measured the cross-section with calipers.

 

Use modeling clay.

 

//www.fordmuscle.com/fundamentals/pistontovalve/

I know, but its all the same and a good one for a biginner.