Weird problem

[CREEP]

I've discovered alot of air coming out of my valve cover with a recent boost leak test. It has trouble building even 5-6psi. PCV is good. Bypassing the turbo by putting the tester on the UICP seems to solve the problem. It builds boost immediatly up to 15psi and only has what i'd consider normal blowby out of valve cover. Motor was rebuilt recently with good even compression. Now the weird part is it doesn't smoke which would support the fact that the compressor housing seal is shot, causing it to get into my oil feed coming from the head. Power is definately down. It's only trapping 100mph at best on a pte scm5031 @20psi. No more than 7 counts of knock.

I'm stumped here. This seems like it could be something simple. Any help would be great. Thanks.

 

[98mitsuGSX-SD]

Redo a boost leak test at the turbo to the UICP. Seal those boost leaks. Since your not able to build pressure at the turbo your leaking around that portion from the UICP back to the turbo. You've already verified constant pressure from the UICP and on.

**Edit** Did you disconnect the BOV line and place a plug on it to take the BOV out of boost leak test?

 

[oldman]

1. It's perfectly normal for pressure to enter crankcase through your oil return (not feed) during a static pressure test because the so call "turbo seal" is simply a metal seal that is pressed up against the CHRA housing via oil pressure. However, this is only true if the turbo has no excessive shaft play which can physically destroy the seal.

2. The BOV line can not be disabled during a leak test because it holds the valve close against the pressure in the UICP, without it, your BOV will open resulting in pressure lost through the BOV return tube. What needs to be disabled is the MBC.

 

[CREEP]

1. It's perfectly normal for pressure to enter crankcase through your oil return (not feed) during a static pressure test because the so call "turbo seal" is simply a metal seal that is pressed up against the CHRA housing via oil pressure. However, this is only true if the turbo has no excessive shaft play which can physically destroy the seal.

Rings maybe then? I am going to re-check compression with a dry AND wet test. Last week though it was even throughout the cylinders at 155 w/ a crappy tester. No excess shaft play or smoke.

I really do appreciate the help guys, this car runs my life.

 

[oldman]

Rings maybe then? I am going to re-check compression with a dry AND wet test. Last week though it was even throughout the cylinders at 155 w/ a crappy tester. No excess shaft play or smoke.

I though you said the problem was gone after you moved the tester to UICP? This is the bottom line, there are 4 locations where pressure air can enter the crankcase during a static pressure test, Turbo, PCV, intake valve seals and piston ring. You sound like you're intelligent enough to eliminate them one at a time on your own. Tip: Testing with a warm motor will help seal the rings better.

 

[CREEP]

Ahhhhhh christ-mas.

Thank you all very much.

 

[CREEP]

New test done right:

Dry: 152-149-145-155
Wet: 168-168-173-171

 

[oldman]

New test done right:

As in all four plugs removed, engine fully warmed up, throttle fully applied and battery fully charged?

Remember, you're only testing one combustion chamber during a boost leak test because only one set of intake valves will be open.

 

[CREEP]

As in all four plugs removed, engine fully warmed up, throttle fully applied and battery fully charged?

Yes, yes, yes, yes.

 

[oldman]

How much oil did you pour in the cylinders? A cap full is all you need, as in the small cap that comes with old style oil bottles.

 

[CREEP]

I put in a cap full. Are you getting at something here?

 

[oldman]

I put in a cap full. Are you getting at something here?

I'm making sure the test was done right because with that kind of increase between dry and wet, I would expect your dry test to be much lower as well as smoke out of your tail pipe.