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Old 04-09-2009, 12:47 PM   #1
methaddict
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Full Race TS, BW 8374 EFR

Default what are causes for excessive crank case pressure?

what conditions make this happen? higher breathing capacity in the heads? stuck pcv? cams?
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Old 04-09-2009, 01:43 PM   #2
berdugo
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not sure, just guessing, some blow by, lots of blow by from worn out piston rings or broken ringlands?
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Old 04-09-2009, 01:43 PM   #3
gto7419
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blow by.... and a crappy pcv system...
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Old 04-09-2009, 04:29 PM   #4
drewdogg
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blow by... bad rings/ringlands
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Old 04-09-2009, 04:58 PM   #5
MartinSTi05
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Don't forget higher cylinder pressure. Even if you have good ring seal blowby will get higher as cylinder pressure increases.
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Old 04-09-2009, 08:52 PM   #6
methaddict
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Quote:
Originally Posted by MartinSTi05 View Post
Don't forget higher cylinder pressure. Even if you have good ring seal blowby will get higher as cylinder pressure increases.
Ok this sounds like this maybe the reason why I was getting blue smoke out my exhaust. Since this is directly related to my other thread, here's a link: "Blue white smoke out of exhaust on newly built motor" I have no play on the turbo shaft and was told by a turbo rebuilder that my symptoms sound like the turbo seal is still good and was getting excessive crank case pressure. We disassembled the motor and all rings and ring lands were intact. I just had some debris in the oil that caused the crank journals to get scored up. I'm getting the crank black nitrided and repolishing the journals. I will install a good air/oil separator and remove the pvc.

Last edited by methaddict; 04-09-2009 at 08:59 PM.
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Old 04-09-2009, 08:58 PM   #7
moorebl
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try the crawford AOSits pricy but a good piece. i even think peeople on here are selling 1 or 2 of them
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Old 04-09-2009, 09:00 PM   #8
methaddict
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I'm going with one by Kelly of Covert Performance.
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Old 04-09-2009, 09:24 PM   #9
gto7419
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Quote:
Originally Posted by methaddict View Post
I'm going with one by Kelly of Covert Performance.
link???

Id like to take a look at these!
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Old 04-11-2009, 07:47 AM   #10
n2oiroc
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a bad compressor side seal on the turbo will do all the things you described.
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Old 04-11-2009, 06:10 PM   #11
methaddict
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Quote:
Originally Posted by n2oiroc View Post
a bad compressor side seal on the turbo will do all the things you described.
I described these symptoms to a couple of turbo rebuilders and they all say the turbo is fine. If it was the turbo it would have been constantly been smoking. They all say it's blow by possibly from a bad pcv.

Last edited by methaddict; 04-11-2009 at 11:35 PM.
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Old 04-11-2009, 07:37 PM   #12
RealStreet
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in the 10's and the bends

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If there is excissive crankcase pressure it can back the drain up and cause the turbo to smoke.This is usually a concern on decel. I don't know that oil sitting in the cylinder will burn during startup because of it's low flash point. Most times you get smoke on startup it's coming from someplace behind the valve, that way you get some fuel in the mix to help light the oil up.

Jay Meagher
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Old 04-12-2009, 07:41 AM   #13
n2oiroc
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Quote:
Originally Posted by methaddict View Post
I described these symptoms to a couple of turbo rebuilders and they all say the turbo is fine. If it was the turbo it would have been constantly been smoking. They all say it's blow by possibly from a bad pcv.
they can say what they want, but i have been there twice now. oil blew out of my catch can a week before any symptoms showed up. then it smoked like hell at startup once, didnt smoke for 200 miles and then smoked like mad again. started sucking a bit of oil before i saw any smoke. the smoke really only starts to show up when the turbine side takes a dump. not all bad seals do this.....


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