sr20det breather setup ??

Thread in 'Technical Questions' started by g6mmc, Aug 26, 2010.

  1. Captain Muppet

    Captain Muppet Pro-tard

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    :D

    This is how all technical threads should be.
     
  2. martinb

    martinb Member

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    information from people that know... not people that have read..
     
  3. BLAZE

    BLAZE Member

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    anyone have a simple how to guide to this for a noob? :o
     
  4. g6mmc

    g6mmc Member

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    #24 g6mmc, Sep 9, 2010
    Last edited: Sep 9, 2010
  5. g6mmc

    g6mmc Member

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  6. Captain Muppet

    Captain Muppet Pro-tard

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    1 - remove WOT breather hose from inlet pipe.
    2 - plumb that hose in to a catch can.
    3 - vent the catch can to atmosphere via a filter
    4 - realise that unless you're running shit loads of boost it won't make a measurable difference to power at all.
    5 - open your bonnet when parked so people can see your shiny catch can.

    You can just disconnect the hose and stick a breather filter on it, but then should you have a massive blow-by event it'll basically become a hose pipe for hot, flamable, oil vapour. No one likes being on fire.

    Really we need a "why-to" guide more than a "how-to". And the "why" is basically that you have increased the engines performance to the point where the standard breather system couldn't cope. Clean your inlet pipework inside, go for a drive, then check it. If it is dripping with oil inside after a short drive then maybe you should do something about it. Whether that something is to vent to atmosphere or fit piston rings that work is your choice.

    Over filling the engine with oil can also cause excessive oil carry over in to the breather system.
     
  7. Captain Muppet

    Captain Muppet Pro-tard

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  8. chrisb

    chrisb Member

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    Thes engines need vacuum all of the time... - SRT Forums - SRT4, SRT6, SRT8, SRT10 & Dodge Forum
    SR Owners... More HP Easy Mod... Catch Can Setup - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum
    Changing PCV Setup--Opinions Wanted - SR20 Forum

    yes my info is assumptions at the min because i am in the process of building my engine because it put all the oil into the catch tank out the dipstick went on fire spun a bearing and threw a rod out of the block, however its important to know that the engine had only approx 1k miles on it with new pistons, rings, all bearings, crank polished balanced, along with the head reconditioned with seals, guides, reseated valves, bc springs. hence no issues with the engine pressurising the crank due to old worn out parts, which is why im assuming that breathing was the issue as the car was mapped running 1.4bar boost venting to the atmosphere.

    i was running no pcv as it was maped to idol without one, then crank vent went straight up to T on rocker then to catch then to atmosphere. dont get me wrong im not saying it will not work venting to atmosphere as all it needs is the pressure to go somewhere but im assuming it will get out of the engine with a little assistance quicker when plumbed into vacume.

    what happened with my own settup i can determine that the oil in the catch was coming from the crank case because when it filled and was not venting to atmosphere any more (ie blocked cause of oil) the pressure came out threw the dipstick as it had no where else to go. then from reading the above topics etc i can see the flaw in the design with the T piece, the oil goes the easiest route and that is straight threw to the catch tank. my options are to modify my rocker cover to have two seperate connections (which is the way a vvt rocker has been designed and im assuming again that this problem doesnt occur with this type) because a pipe is then run straight from the block to the head, and any oil that is present will drain threw the head to the block again leaving just the vapour to deal with. this is where the second connection comes into play, i will run it to the catch tank and then to the intake behind the filter but before the afm

    only reason i am going to apply a vacume is because in one of the topics above it has been proven with dyno runs that vacume apposed to no vacume does have an advantage

    the main issue is the poor design of the 180sx rocker cover

    im hoping to have everything up and running again in a couple of weeks and i will report back on how its working or possibly not if thats the case

    chris
     
    #28 chrisb, Sep 9, 2010
    Last edited: Sep 9, 2010
  9. chrisb

    chrisb Member

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    i think from reading that you have a vvt engine?

    which has two connections already in the rocker cover?

    thats what im hopefully going to achieve by either welding a vvt and non vvt together or the simpler way by adding a connection to my nonvvt cover like done in one of the topics i posted

    can other people that have had issues or had no issues state weather or not its vvt or non vvt rockers cause i think this is where the problem is occuring

    maybe im wrong to assume and yes im guessing that all problems are with nonvvt heads and vvt heads are fine

    thanks
    chris
     
  10. chrisb

    chrisb Member

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    lol you guys are going to be sick of me replying to everything but im gona try everythin to hopefully prevent me blowing another engine

    correct pcv only works at idol, ive mapped it out of the equation which effectivly means i can block it off completely? the power issue is at wot

    what does everyone think?
     
  11. chrisb

    chrisb Member

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    vvt or non vvt rocker?
     
  12. chrisb

    chrisb Member

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    from everything then i am assuming everyone knows where im coming from?

    which for me means that the picture above is completely wrong, ie the pressure from the crank will go straight up threw the t into the intake again which looks to be before the afm which means unmetered air into the intake. and no catch can unless standard one is behind that heat shield will mean oil and vapour which if they get the pressure i experienced the intercooler will be filling with oil with no warning


    someone stop me my head is fried lol
     
  13. g6mmc

    g6mmc Member

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    brilliant help there chris, cheers
     
  14. JohnJ

    JohnJ Active Member

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    @chrisb - Mine is a vvt engine, you're right.

    I think you've misdiagnosed your own engines problems. I'm fairly sure something failed causing so much crankcase pressure. How did you run it in?

    If you hadn't put the catch tank in, the oil would have gone through the inlet!
     
  15. chrisb

    chrisb Member

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    was run in before the mapping and ran at 340hp settup for 6 campionship rounds and a couple of practice days, then turbo blew, while i was up grading i took head off and got new guids and seals in because that wasnt done when i got the valves seated and also bc springs, then mapped for same boost but running bigger turbo and external gate settup

    before at 340 i would have filled a catch tank every two events but at 380-400 it was every few laps

    ive learnt the hard way on how oil starvation really kills an engine, got my head back today and it needed new guids and seals which i assume also went due to the lack of oil as all were practically new when i took the car out that day.
     
  16. bigrichy

    bigrichy Team Beard

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    Yeah, that'll ruin a day out alright :no::(
     
  17. g6mmc

    g6mmc Member

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    what does anyone that actually knows about these rockers think ?
     
  18. JohnJ

    JohnJ Active Member

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    Chris my SR runs at 370 bhp with 740 injectors, 2871R etc. It is used hard on track 2 / 3 times a month. Yesterday it had customers driving it asll morning and then passenger rides in the afternoon.

    That was 120 X 45 second runs yesterday afternoon.

    Next Sunday it will have the same kind of day at Buxton.

    It has had this lifestyle at this power for a year and has not yet filled the catch can once.
     
  19. JohnJ

    JohnJ Active Member

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    I have just been out and checked the catch can after yesterday and there's maybe half an eggcup of oil in it.

    It's not your breather that's at fault I don't think.
     
  20. chrisb

    chrisb Member

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    you have vvt rocker so oil get redirected threw the head back to the block leaving only vapour coming out the other port to catch tank. the only way to tell if you car would be doing the same is to put a catch tank between the block and rocker.

    chances are alot of vvt cars in the country are doing the exact same thing only noone realises because of the better rocker design

    the vast amount of nonvvt competition cars i have looked at over the past few weeks seem to have the same problem, almost everyone of them had the dipstick cable tied in and engines soaking with oil from breather.

    i think there is a very good reason nissan had the small black catch can between the block and the T in the rocker, il be cutting my old one in half to see how well its baffeled
     

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