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PVC Valve or Valve Cover Breathers

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Old Oct 26, 2009 | 12:14 PM
  #1  
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From: Northern Kentucky
Car: 1991 Trans Am GTA, 2003 Grand Am GT
Engine: 350 Tune Port
Transmission: 700R4
PVC Valve or Valve Cover Breathers

I just purchased new valve covers and they come with a breather in each cover, which look much better than the PCV tube. Can I block off the PCV valve port in the intake and just run the breathers or much I have the PVC valve?

Thanks!
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Old Oct 26, 2009 | 12:36 PM
  #2  
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From: Philly, PA
Re: PVC Valve or Valve Cover Breathers

You can, but you may not like the oily mess on your valve covers after you drive it a while.
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Old Oct 26, 2009 | 12:44 PM
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From: Enschede, Netherlands
Car: 82 TA 87 IZ L98 88 IZ LB9 88 IZ L98
Engine: 5.7TBI 5,7TPI 5.0TPI, 5,7TPI
Transmission: T5, 700R4, T5, 700R4
Axle/Gears: 3.08, 3.27, 3.45, 3.27
Re: PVC Valve or Valve Cover Breathers

PVC = polyvinylchloride...a plastic
PCV, run the PCV...no sense in running dual breathers on a street car. The PCV does help keep your oil clean and may provide a little better ring sealing. Breathers stink up the engine bay and interior. The only reason to run them is if you don't want the PCV to dillute your intake and mess up fuel distribution on a race engine. If anything, run scavenge tubes in your collector and hook the PCV to that.
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Old Oct 26, 2009 | 02:05 PM
  #4  
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From: Northern Kentucky
Car: 1991 Trans Am GTA, 2003 Grand Am GT
Engine: 350 Tune Port
Transmission: 700R4
Re: PVC Valve or Valve Cover Breathers

Whoops, I always confuse PVC and PCV. Thank you for the info! As you mentioned, I am going to stay with the PCV. Would you mind expanding on what you mean by "run scavenge tubes in your collector and hook the PCV to that" I am not quite sure what you mean.

Also, should I remove the vent in the other valve cover and replace it with an oil cap?
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Old Oct 26, 2009 | 02:29 PM
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From: Enschede, Netherlands
Car: 82 TA 87 IZ L98 88 IZ LB9 88 IZ L98
Engine: 5.7TBI 5,7TPI 5.0TPI, 5,7TPI
Transmission: T5, 700R4, T5, 700R4
Axle/Gears: 3.08, 3.27, 3.45, 3.27
Re: PVC Valve or Valve Cover Breathers

45 degree tubes on the collector with a check valve on top so that the exhaust pulses pulla slight vacuum.

Moroso sells a weld in kit but if you have some old smog legal headers or manifold you can simply chop the top of the air tube off a set of old headers (the section with the NPT thread where the check valve threads onto) and weld those on the collector at a 45 deg. angle.

Last edited by Twin_Turbo; Oct 26, 2009 at 02:55 PM.
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Old Oct 26, 2009 | 02:33 PM
  #6  
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From: Northern Kentucky
Car: 1991 Trans Am GTA, 2003 Grand Am GT
Engine: 350 Tune Port
Transmission: 700R4
Re: PVC Valve or Valve Cover Breathers

Thanks for the explanation. I am actually running Hooker 2460's w/o air tubes. I guess the simplest thing to do is just connect the PCV valve. Not a big deal, the valve cover breathers just looked really good. Is there anything worng with running a breather on the opposite side of the PCV valve?
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Old Oct 26, 2009 | 08:36 PM
  #7  
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From: Philly, PA
Re: PVC Valve or Valve Cover Breathers

Nothing wrong with it at all. PCV valve in one and breather in the other is exactly how it should be done.
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