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07-15-2013, 11:56 AM
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#1
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Super Moderator
Join Date: Dec 2007
Posts: 6,850
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Turbo I4 Diagnostic Troubleshoot Excessive Crankcase Pressure
All in the title. Turbo I4 has an issue with excessive crankcase pressure.
The head was warped so bad it had to be resurfaced but the cams still rocked from the head being bowed. So a crack in the head was a definite suspect. We pulled the head, but cannot see any cracks. And the area between the combustion chamber and the crankcase is THICK, which makes me second guess the diagnosis.
Piston walls look kinda shiny, but there is still evidence of cross hatching. Plus there was no issue with ring blow-by before the over-heating/ HG failure/ head warpage issue. Which makes me second guess poor ring sealing.
No blow by into the coolant. No oil contamination. HG was new MLS, no evidence of blow by into a crank case pressure port from the HG.
Ideas?
__________________
I <3 forced induction.
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07-15-2013, 12:08 PM
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#2
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Fast & Filthy
Join Date: Jun 2008
Posts: 3,840
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How can you tell it has excessive crankcase pressure?
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07-15-2013, 12:34 PM
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#3
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Super Moderator
Join Date: Dec 2007
Posts: 6,850
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It is pushing oil out everywhere, intake, valve cover seal, spark plug seals (on top), pcv popping out.
It is a symptom, mechanic confirmed.
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I <3 forced induction.
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07-15-2013, 12:38 PM
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#4
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Fast & Filthy
Join Date: Jun 2008
Posts: 3,840
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I've only seen that with a blown head gasket on a boosted engine.
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07-15-2013, 05:21 PM
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#5
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Senior Member
Join Date: Jun 2009
Posts: 2,509
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Is the PCV even working?
__________________
93 GMC Typhoon: new money pit/PITA. Now GT3788R powered.
Boost, because sometimes atmospheric pressure just isn't enough.
"If it has tit's or tires, you can be pretty sure your going to have problems with them..."
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07-15-2013, 07:49 PM
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#6
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Super Moderator
Join Date: Dec 2007
Posts: 6,850
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Not under boost, it should really be hollowed out and routed to the intake. I did that with mine, it helped a lot.
__________________
I <3 forced induction.
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07-15-2013, 07:51 PM
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#7
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Super Moderator
Join Date: Dec 2007
Posts: 6,850
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Quote:
Originally Posted by 94cobra69ss396
I've only seen that with a blown head gasket on a boosted engine.
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The crankcase port that runs from the block through the head is only a 1/2" single port. Not likely, but possible.
__________________
I <3 forced induction.
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07-15-2013, 11:55 PM
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#8
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Senior Member
Join Date: Jun 2009
Posts: 2,509
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Quote:
Originally Posted by enkeivette
Not under boost, it should really be hollowed out and routed to the intake. I did that with mine, it helped a lot.
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The Typhoon actually has 2 PCVs on the same valve cover. One goes to the TB, the other goes to the intake pipe before the turbo. Under boost, there is enough suction on the intake to pull a vacuum on the vent.
__________________
93 GMC Typhoon: new money pit/PITA. Now GT3788R powered.
Boost, because sometimes atmospheric pressure just isn't enough.
"If it has tit's or tires, you can be pretty sure your going to have problems with them..."
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07-16-2013, 09:47 AM
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#9
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Super Moderator
Join Date: Dec 2007
Posts: 6,850
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Nice
__________________
I <3 forced induction.
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07-16-2013, 10:02 AM
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#10
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Senior Member
Join Date: Jun 2009
Posts: 2,509
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Maybe try something like that with this car?
__________________
93 GMC Typhoon: new money pit/PITA. Now GT3788R powered.
Boost, because sometimes atmospheric pressure just isn't enough.
"If it has tit's or tires, you can be pretty sure your going to have problems with them..."
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