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Valve Cover breathers or Catch Can?

Discussion in 'Terminator Talk' started by Silverboost, Jan 10, 2017.

  1. Silverboost

    Silverboost Active Member Established Member

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    So what's the verdict on this? I know with going with valve cover breathers you will get fine oil mist on the motor, but it definitely keeps the garbage out of the engine. I am leaning this direction as there is less hoses running around the engine bay, but just looking for suggestions.

    Thanks,
    Mike
     
  2. toomanytoys

    toomanytoys Member Established Member

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    After doing breathers I could smell the engine inside of the car. That's all it took to go catch can. Haven't smelled it since
     
  3. 03cobra#694

    03cobra#694 You Guys... Staff Member Super Moderator

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    Catch can myself, oil mist would drive me nuts.
     
    BlksvtCobra01 likes this.
  4. speedoflife

    speedoflife Member Established Member

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    This has been discussed as naseum on this site:

    http://lmgtfy.com/?q=site:svtperformance.com+catch+can+or+breather+cobra

    My opinion: any air that enters/exits the engine system post MAF (aka unmetered air) is not good. Maybe it will cause problems. Maybe not. Why risk it? And breathers are messssssy. That eliminates breathers.
    So....
    Catch can (and/or prefilter if you would like) on drivers side. Catch can and/or prefilter on passenger side.

    I personally vote for catch cans (enclosed) on both sides and a prefilter on the drivers side so the can doesn't fill up as fast.

    This one's really a no-brainer.
     
  5. MalcolmV8

    MalcolmV8 Well-Known Member Established Member

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    If you can live with the oily mess and smell breathers on the valve covers will work for you. I ran mine to catch can which solved the oil issue but not the smell. So instead of a breather on the catch can I have a hose that runs to the exhaust and bleeds in just after the X pipe.

    More specifically I only have a catch can on the passenger's valve cover. The driver's valve cover just goes directly to the exhaust. In my testing with dual catch can setups I never ever got oil in the driver's side. Only the passenger's side will collect oil. So why have the extra weight of a second can on the driver's side catching nothing but moisture?
     
  6. speedoflife

    speedoflife Member Established Member

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    My drivers side catch can definitely catches a good amount of oil. Not to say that is representative of everyone's car, but most people catch oil on the drivers side.

    Dumping the drivers side into the exhaust is a solution for sure. Does your exhaust leave more soot than normal?
    That still opens up a closed-loop system to the "atmosphere." To each their own on that one.

    And if you're worried about the weight of a catch can (relative to the benefits of catching misted oil), just take a poop before you go drive your Cobra. That's maybe 2-3 lbs added?
     
  7. MalcolmV8

    MalcolmV8 Well-Known Member Established Member

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    Is that with both valve covers freely open and the PCV system deleted? If so I've seen that on multiple cars and the passenger's side is always the side catching oil. Now when guys do custom setups and partial PCV systems where one valve cover is vented and the other goes to the lower intake or to the intake tube etc. then yeah it changes things.

    No because as I mentioned before the driver's side on my car is just moisture. No oil. The passenger's side has a catch can because it catches oil.
    I have no "closed-loop" system as you called it. I deleted the PCV a long time ago to keep oil out of my intercooler. It would not pass emissions in a state that requires it but other than that its fine.

    Again there's no misted oil on my driver's side. My passenger's side has a catch can.
    It didn't make sense to have a can with all the AN fittings and complexity on the driver's side, not to mention how short of real estate I am for space, when a simple hose straight to the exhaust does exactly the same job. I was pointing out the weight savings is just a bonus.
     
  8. DSG2003Mach1

    DSG2003Mach1 Well-Known Member Established Member

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    I tried breathers, couldnt stand the smell (probably made worse by being a new motor not broken in yet). I put everything back and put the JLT filter kits in place
     
  9. MalcolmV8

    MalcolmV8 Well-Known Member Established Member

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    Nope it smells all the same, breaking in or many miles. It stinks.
     
  10. DSG2003Mach1

    DSG2003Mach1 Well-Known Member Established Member

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    I was just thinking there may be more vapor as the rings seat is all, had some issues and ended up with a lot of idle time before I could put it under a load.
     
  11. MalcolmV8

    MalcolmV8 Well-Known Member Established Member

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    I've been there, it sucks. Did the rings still seat?
     
  12. DSG2003Mach1

    DSG2003Mach1 Well-Known Member Established Member

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    I guess? Not really sure how to say for sure. I talked to the builder, he said they should still seat it would just take a little longer. The car doesnt smoke out the tailpipes, the minuscule oil use appears to be accounted for by the veeery slow leak from the moroso oil pan, no fuel smell in the oil etc...car runs like a raped ape, will be on the dyno soon. The catch can isnt filling up super fast or anything
     
  13. MalcolmV8

    MalcolmV8 Well-Known Member Established Member

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    Sounds like you're good. When they don't seat you get a lot of blow by, low compression on tests and generally the car burns oil and smokes a little. Usually fouls plugs fairly often although not always.
     
  14. speedoflife

    speedoflife Member Established Member

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    That all makes sense. Everybody's setup is so different that it's hard to judge from the internet.

    If I could get away with it, I would just delete the system as you have.... that's the best solution.
     
  15. Silverboost

    Silverboost Active Member Established Member

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    Can you post a pic of your set up? Having a hard time envisioning it tonight!


    Sent from my iPhone using Tapatalk
     
  16. ctgreddy

    ctgreddy Active Member Established Member

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    I've had regular breathers on my car for the past 3 years. Every couple weeks I'll wipe off my valve covers but there's very little oil residue. And I've never had an oil smell.

    Every engine's different just like said above but I love my setup. Cheap easy looks nice and zero issues with no smell.
     
  17. Rambro

    Rambro Active Member Established Member

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    Breathers here for the past two years and no issues. Very little residue and there is a faint smell but it's not enough to bother me or make me want to play the catch can game again. I had a catch can and pre filters and still had oil in my intake, waste of money IMO.
     
  18. MalcolmV8

    MalcolmV8 Well-Known Member Established Member

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    That's why I deleted the PCV and my catch can doesn't go back to the intake manifold. While it does slow down oil it'll never completely stop it. Manifold vacuum will always get some oil in.
     
  19. 2011 gtcs

    2011 gtcs GT500 poster Premium Member

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    My PCV lines are deleted and I run twin metco motorsport breathers. I have no oil spell at all surprisingly and no oil mist at all.
     

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