[Heath]

I decided to build a homemade pressure tester using a pvc cap with a schrader valve. I coupled it to my turbo intake and used my air compressor to pressurize the system.
The first thing I found was air leaking from the bpc solenoid. The vacuum line I used to block off the two unused nipples (mbc+a installed but not yet fine tuned) had popped off the center nipple. Easily remedied.
Next, and even more noticeable once the first leak was fixed was the large volume of air escaping through my oil cap. This concerns me. Should it? I removed the check valve from the vacuum line running from the valve cover to the intake manifold/tb and tested it. Air passes through only one way. I have the arrow pointing to the intake, away from the valve cover. Air can pass from the crankcase to the intake but not from the intake to the crankcase.
That leaves me where? Is the pressurized air flowing through the tb in to the head and past the valve stems? Is it entering through the open valves then passing the rings to the oil pan? Engine has around 87k.
A couple months ago I removed the valve cover and cleaned the vent system thoroughly using carb cleaner and compressed air to dry. There should be no restrictions. Everything looked good.
What variable(s) am I missing?

 

[ppap]

A smoke machine works in the same manner but with a visual at the source of the leak.
How much pressure was your compresser set for?

 

[earthworm]

I hope that the pressure was not too high..

Some things may have vent holes, so you would have to know these details.

But I think this is a very interesting idea with merit..

 

[Heath]

I started the pressure at 12psi and then worked on up to around 40psi. The thing is it was leaking so badly the pressure wouldn't hold and was gone within two seconds of removing the line from the valve. I could run to my open car door and look in at my boost gauge and never see it register anything other than "0"
I would be surprised if the system saw more than 10psi to be perfectly honest. I plan to retest since it has been suggested a bone cold engine (55 degrees) would not seal properly and the internals, particularly the rings, need to be hot.
I really don't know where else to check.