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Crankcase pressure = leaky turbo?

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Old 06-23-2005, 08:09 AM
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Default Crankcase pressure = leaky turbo?

Has anyone ever had crankcase pressurization cause a turbo to leak oil into the compressor housing? Turbos are GT series with the stock oil restrictors, mounted about level with the valve covers...drain lines are -10 with no kinks or upward angles, so it deffinately isn't a gravity problem. Only thing I can imagine is the PCV pressurizing the case and oil backing up that way?

We cleaned the oil out of the I/C and piping, then ran the PCV to a catch can and from there to just before the turbo inlets. Hopefully this will solve the problem.

Anyone else have suggestions?
Old 06-23-2005, 09:57 AM
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You do have some kind of one way check valve between the intake and PCV so the boost doesnt pressurize the crankcase right?

Too small of air filters will cause oil to be drawn from the seal as well. I would take the crankcase breather lines off the inlet for now and se if the problem stops before I did anything.
Old 06-23-2005, 08:03 PM
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Seems to be a common problem with the Garrett GT series.
Old 06-23-2005, 08:16 PM
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I'm having the same problem...this guys turbo looks like mine
http://www.turbomustangs.com/forums/...threadid=42598

reading that post now myself...
Old 06-24-2005, 01:40 AM
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i had issues initially with mine not draining. dry sump, sealed crankcase, until the pump would pull enough vac the drains would back up.

small vent line solved the issue.
Old 06-24-2005, 03:47 PM
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YES. I JUST resolved this problem a couple days ago. I went to a local car parts store and bought a brake booster check valve and put it in the crankcase vent tube going from my passenger valve cover to the throttle body. Haven't seen oil since...
Old 06-24-2005, 04:23 PM
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I thought that you shouldn't have any lines going to the TB anymore. My TB and intake holes are capped off....been that way as per PD and ATI?

John from limit engineering emailed me today
------------------------------------------------------------------------
Jeremy,

This is the most common problem with retrofit kits.

-10 drain is too small for a GT42. Should be at least -12 with
as few turns as possible. MUST be going down at all times
(never horizontal or up). Must terminate in the pan above the
oil level.

How much oil pressure do you have? Hot? Cold? How do you
ventilate the crankcase? Carburetor or EFI?

For your information, the seal (piston ring) on the exhaust side
of a turbocharger is not an oil seal, it is an exhaust seal. It is
there to keep the exhaust gases form contaminating the crank-
case.

Regards,

John C. Craig

Limit Engineering, Inc.
Performance Turbochargers
Garrett Performance Distributor
--------------------------------------------------------

So take it FWIW, I'll be looking for a -12 return line now and bigger fitting for the oil pan.
J
Old 06-24-2005, 07:14 PM
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Originally Posted by frcefed98
I thought that you shouldn't have any lines going to the TB anymore. My TB and intake holes are capped off....been that way as per PD and ATI?

John from limit engineering emailed me today
------------------------------------------------------------------------
Jeremy,

This is the most common problem with retrofit kits.

-10 drain is too small for a GT42. Should be at least -12 with
as few turns as possible. MUST be going down at all times
(never horizontal or up). Must terminate in the pan above the
oil level.

How much oil pressure do you have? Hot? Cold? How do you
ventilate the crankcase? Carburetor or EFI?

For your information, the seal (piston ring) on the exhaust side
of a turbocharger is not an oil seal, it is an exhaust seal. It is
there to keep the exhaust gases form contaminating the crank-
case.

Regards,

John C. Craig

Limit Engineering, Inc.
Performance Turbochargers
Garrett Performance Distributor
--------------------------------------------------------

So take it FWIW, I'll be looking for a -12 return line now and bigger fitting for the oil pan.
J
Good info, thanks. I'm picking mine up in the morning, hopefully we have solved the problem. I'm running a 9200 Weldon but have still been having issues.



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