I have never done a leak down test and would like to learn how. Where can i find such information? Or can someone tell me how to do such a test? Any help will be Greatly Appricatied!

 

Do a search on "leak down test", in the last couple of weeks, the entire spec of a procedure with the orifice sizes and all that was posted.

 

To perform acylinder leakage test, you'll need a reliable source of compressed air, a pressure regulator, and a cylinder leakage tester.

The compressor will have to maintain at least 100 PSIG for the test, and is the most expensive component needed. If you don't have and didn't plan to get one, you can either have someone else perform the test or borrow/rent a compressor.

You can purchase a cylinder leakage tester for right around $120, or build your own for about $30. If you already own a compression tester, hopefully it is NOT the type that is simply held against the spark plug opening, but has a hose/fitting that threads into the spark plug hole. The first type is notoriously inaccurate, mostly from poor sealing and leakage. If you have the type with a hose/fitting, you already have the most difficult/uncommon part in your hands - the adapter hose. Find a quick connect fitting that will mate with the one on your compression tester, or change both fittings on teh compression tester to a more commonly available type. If the tester doesn't already have a quick disconnect fitting, install one. Assemble a manifold from two ¼" NPT "Tees", a couple of mating quick-connect fittings, and one specially modified ¼" NPT nipple between the two "Tees" as such:



The nipple needs to be plugged with a solid material that can either be brazed or silver soldered in place. A small section of bolt or other plug would be suitable. Through this plug you will drill a 1.0mm hole (0.040") using a 1.0mm or #60 drill. This is the "secret" controlled orifice that makes the leakage testers work. The orifice regulates the flow of air to the cylinder, and in that way creates a pressure differential between the two gauges. The greater the flow (cylinder leakage), the greater the differential.

Set the regulator at 100 PSI for the incoming (line) gauge and monitor the leakage (cylinder) gauge to compare the two readings. Using 100 PSIG on the line gauge makes the percentage calculations direct - 100 PSIG in and 85 PSIG out = 15% leakage. It's that easy.