I am trying to build my own cylinder leakage tester using very accurate guages and regulator. Has anyone ever build their own and how do I figure how big of a restriction I need between the guages. I am going to be testing leakage on other things besides engine cylinders. I'm looking for a formula to calculate the restriction. Any help or input will be greatly appreciated.

I was thinking of doing the same thing and I found a good one in the Summit Racing catalog for $65.00. Too cheap to be screwing around making a homemade one.

Just buy one. After buying 2 guages and a regulator, it's more trouble/cost than it's worth.
But if you've got A LOT of free time. Here are instructions:
http://www.xs11.com/tips/misc/misc3.shtml
Gary

Ed ck out the instructions , it says ck em with the pistion down?

http://images.google.com/imgres?imgu...LD:en%26sa%3DN

Yeah but you need to loosen all the rockers so the valves stay closed.
If you check at TDC, the engine could turn over if it's not exactly at TDC. That's especially true on small engines. You'll find it hard to get 100psi in a 4 cylinder without it turning over.
The solution, use 30-50 psi to test.
Gary

[QUOTE=Strip Poker 388]Ed ck out the instructions , it says ck em with the pistion down?

I see that! I usually keep tapping the remote starter switch until the piston is at TDC on the compression stroke. If the engine moves, I start over.
I never checked leak-down at BDC because it's a lot of extra work to loosen the rocker arms and then adjust them again.
Depending on the headers, sometimes just pulling the valve covers is a royal PITA!

[QUOTE=Edward R. Cozzi]Thats the way I do it also. I was always told you wouldn't get a correct reading at the bottom of the bore.

As a cylinder wears,it wears more at the top than at the bottom, it tapers. It kind of makes sense, because I would think there is more pressure on the rings higher up in the cylinder. So in my opinion you would get a better idea of cylinder condition testing differential at TDC rather than BDC. Doug

Some will tell you to check at TDC beacuse of the cyl taper. Some say check at BDC to check for cracks in the cyl wall. If you are already set to do it, both is not the worst idea. Also if the number gets better at the bottom, you got some block wear to deal with

I do both. Found a problem this winter with a cylinder that I wouldnt have found if I just did top. Skirt had hurt the cylinder wall, didnt show at TDC of course.