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View Poll Results: PCV Options
Leave it alone.
15
11.11%
Add a catch can.
47
34.81%
Change to a truck PCV valve.
9
6.67%
Remove the entire system and run a breather.
64
47.41%
Voters: 135. You may not vote on this poll

What to do with PCV system?

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Old 02-01-2006, 01:15 AM
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Originally Posted by BackinBlack02SS

EDIT: Anyone know the gm part number for the red vaccum cap pictured here? http://www.ls1howto.com/howto/geniii...erside_pcv.jpg


you can by them at autozone or checkers for like $3.00 for a whole kit, theay are exactly the same
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Old 02-02-2006, 05:47 AM
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Write up would be awesome. This would decrease the clutter on my new 408!
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Old 02-02-2006, 02:15 PM
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Originally Posted by 2002covtz28
i thought you just needed the one on the passenger side and cap everthing else off, so is it more saft to have it on the drivers side as well?, is it needed
I would have one on the drivers side as well IMO since some people with one breather were having problems with oil leaking out of their valve cover seals and oil pan seal.
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Old 02-02-2006, 05:49 PM
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Originally Posted by SmaknaSS
I would have one on the drivers side as well IMO since some people with one breather were having problems with oil leaking out of their valve cover seals and oil pan seal.
Where are these people? It would be nearly impossible to create enough positive pressure to force oil out of any seals.
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Old 02-02-2006, 05:53 PM
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Forged my engine and replaced it with a LS6 PCV system ... valley cover and all ... of course, that was not an option in the poll, so, I said scrap it and go with the breather.
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Old 02-02-2006, 07:19 PM
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if u remove anything how are u creating vacuum in the crankcase? isnt that part of the reason its on there?
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Old 02-02-2006, 07:54 PM
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Originally Posted by ls2 bait
if u remove anything how are u creating vacuum in the crankcase? isnt that part of the reason its on there?
There isn't much vacum in the stock PCV system. the PCV valve actually closes when your motor is producing vacum. when there is less or no vacum (ie: WOT) the valve opens to let the crankcase pressure into the motor.
If there was full vacum going thru your PCV you would probably go thru a quart a day.
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Old 02-02-2006, 08:38 PM
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Originally Posted by SUX2BU
There isn't much vacum in the stock PCV system. the PCV valve actually closes when your motor is producing vacum. when there is less or no vacum (ie: WOT) the valve opens to let the crankcase pressure into the motor.
If there was full vacum going thru your PCV you would probably go thru a quart a day.

While I agree with most of what you said, I think you have it backwards. The pcv valve is open under vaccum conditions and closed when there is no vaccum (WOT). When you have the pedal to the metal there is no crank case pressure being evacuated.
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Old 02-02-2006, 09:22 PM
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well is the motor getting a vacuum from somewhere else then? seems to me that for an everyday car that doesnt run wot most of its life that this could cause premature seal failure. please correct me if im wrong-im trying to learn.
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Old 02-02-2006, 10:29 PM
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Originally Posted by BackinBlack02SS
While I agree with most of what you said, I think you have it backwards. The pcv valve is open under vaccum conditions and closed when there is no vaccum (WOT). When you have the pedal to the metal there is no crank case pressure being evacuated.
Actually my furry little friend, duruing WOT is when there is the MOST crankcase pressure.
Ever see a car on the dyno with a bad front main seal? The higher the rpm's the more oil it pukes out of the bad seal.
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Old 02-02-2006, 10:32 PM
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Originally Posted by ls2 bait
well is the motor getting a vacuum from somewhere else then? seems to me that for an everyday car that doesnt run wot most of its life that this could cause premature seal failure. please correct me if im wrong-im trying to learn.
please rephrase your question.
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Old 02-02-2006, 10:39 PM
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So...how about that writeup...
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Old 02-02-2006, 10:40 PM
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Originally Posted by SUX2BU
Actually my furry little friend, duruing WOT is when there is the MOST crankcase pressure.
Ever see a car on the dyno with a bad front main seal? The higher the rpm's the more oil it pukes out of the bad seal.
This is true, but you missed the point. The pcv valve is only open during vaccum situations. Vaccum does not occure under wot. Do you see where I am leading with this, "my furry little friend?"

Last edited by BackinBlack02SS; 02-02-2006 at 11:31 PM.
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Old 02-02-2006, 10:42 PM
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Old 02-02-2006, 10:47 PM
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Originally Posted by BackinBlack02SS
This is true, but you missed the point. The pcv valve is only open during vaccum situations. Vaccum does not occure under wot. Do you see where I am leading with this "my furry little friend?"
True: vacum does not occur at WOT
Thats the only part you got right.
If the valve is closed at WOT (while the engine is producing the most crank case pressure) where does that pressure go? It blows out the seals if your right.
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Old 02-02-2006, 10:49 PM
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Originally Posted by SUX2BU
True: vacum does not occur at WOT
Thats the only part you got right.
If the valve is closed at WOT (while the engine is producing the most crank case pressure) where does that pressure go? It blows out the seals if your right.
Not unless you have an extreme amount of blowby. Most short WOT burts won't create enough crank case pressure to do any damage regardless. Think about it. Vaccum is what opens the valve. When there is no vaccum the valve is closed.

EDIT: Short summary: The stock LS1 pcv system does not evacuate crank case pressure under WOT.
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Old 02-02-2006, 10:54 PM
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Originally Posted by BackinBlack02SS
Not unless you have an extreme amount of blowby. Most short WOT burts won't create enough crank case pressure to do any damage regardless. Think about it. Vaccum is what opens the valve. When there is no vaccum the valve is closed.

EDIT: Short summary: The stock LS1 pcv system does not evacuate crank case pressure under WOT.
BOOYAKAH!
http://www.advanceautoparts.com/engl...0050101pv.html
At idle the engine isn't working very hard and the valve remains mostly closed, allowing a small amount of the crankcase gases back through the engine. At full throttle the engine works harder and creates more crankcase gases, so the PCV valve opens wide to let more through. If the valve gets gummed up with gunk it won't meter properly.
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Old 02-02-2006, 10:57 PM
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Just Google "how a PCV valve works"
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Old 02-02-2006, 11:00 PM
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If the engine is able to create enough crank case pressure the ball will be pushed open, but even then, there is not much that can be evacuated through that tiny opening. GM has a tsb for excessive oil usage regarding the pcv valve. It specifically states that this problem is prevelant with most manual transmission cars that use the engine to slow the car down after high rpm use, aka a ton of vaccum being created. I shouldn't have said the stock pcv system doesn't evacuate pressure under WOT. It does, just not enough IMO. Either way, I like the breather idea better. Eliminate oil consumption and vent more crank case pressure.

Last edited by BackinBlack02SS; 02-02-2006 at 11:31 PM.
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Old 02-02-2006, 11:32 PM
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Originally Posted by ls2 bait
well is the motor getting a vacuum from somewhere else then? seems to me that for an everyday car that doesnt run wot most of its life that this could cause premature seal failure. please correct me if im wrong-im trying to learn.
vacuum occurs during normal everyday driving right. so where is it going to go if its not going thru the pcv? i like the idea however it just seems as though this would be bad for the seals on my motor.
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