Leakdown Tester and ?'s

[Fisherman]

I am building one for general use... Actually prompted by harbour freight having a regualtor for only 2.99 on sale right now...

So I am building a manifold to do the testing. The following drawing depicts my simple design. I figure you could either have the guage mounted on the testing manifold or use the injector hole with a compression guage inserted and feed air to the system via the glow plug hole. Probably best to mount it on the manifold but I already have the compression tester and could use a gas tester that reaches 300 PSI if this is high enough. This one does not have a schrader valve in the intake end of the hose.

One other anomaly I noted in their testing procedure is that they state the pressure loss values atr various points but how in the world can you tell if you losing 15% at the rings and 10% at the valves? Put a flow control meter on the valve cover/tailpipe and intake/exhaust manifolds and... Well you get my point.

I was researching this procedure however and see no specs for the pressure constant (PSI) to load to the cylinder. It also seems a little odd to me that they would suggest this be done at TDC since what if you have a cracked block below the rings at TDC? Testing at TDC would not find this crack so wouldn't it be more effective to test at the bottom of the intake stroke? You also would not have to worry about your pressure pushing the piston down either at that point in the cycle.

Okay, be gentle I did this drawing in about 5 minutes....I did not pick the colors but let the program default...