Build a compression tester?
 

I've got a leak down test kit that has all the hoses and such to attach to a head. I got me thinking, is there anything special about the gauge of a compression tester that I couldn't find a gauge of the proper range and make my own compression tester?

John I have one you can use...

You need a gage, a spark plug adapter and a check valve that will hold the air. And a way to release the air.

And you can't put all that together any cheaper than they can in China. Go to Pep Boys and buy one.

I'll have to take you up on that Jon......

I have the spark plug adapter and a ton of fittings adapters and other goodies, may even have the gauge, plus I'm a member of the "why buy what I can build" club.

If you really want to build it:

You can use a tire valve as the check valve. Just slide a rubber sleeve on the OD and adapt it a gauge. Push it into the hole and voila, you have a peak-hold pressure gage.

You just need to reach inside it to push the valve stem and release the trapped air.