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Crankcase Pressure Under Boost?

Discussion in 'Forced Induction' started by atari, May 7, 2003.

  1. atari

    atari Junior Member

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    OK here is my problem. Fully built motor.(has been run in 6 months) I was having boost leaks so i blocked off the inlet to the turbo, oppened the throttle body and hooked a bicycle pump to one of the vacuum lines. Im not holding more than 5-6 lbs. i think im leaking at the t/b or manifold. So here is my question. im building up pressure in the crankcase.
    This doesnt seem right.
    do i need to have the motor at tdc? to avoid valve overlap? that shouldnt matter...
    am i leeking at the rings? they havent seem oil in a while...
    built the motor last year 1000k break-in and stored for winter.
    any ideas?
     
  2. pissedoffsol

    pissedoffsol RETIRED

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    the crankcase is part of the vacuum system. Hence, the PCV, or positive crankcase ventilation valve. are you running any sort of catch can? breather? or did you tap into your charge pipe to run the stock-like hose to the air intake pipe just before the throttle body?
     
  3. atari

    atari Junior Member

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    Ok im running a catch can but its disconected and it in no way connected to the intake or anything else for that matter.
    ive got pressure coming out of the -an fittings on the valve cover? I know this seems like really simple stupid shit but ive had sooo many problems im just narrowing things down
    thanks
     
  4. pissedoffsol

    pissedoffsol RETIRED

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    you should hook it back up. you need the IM sucking in from the cover to the chage pipe, cleaned of course by the catch can, so that it creates suction, and sucks the shit out. if you don't, it sits in your valve train.
     
  5. atari

    atari Junior Member

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    i understand i need it hooked up for driving purposes but for pressure testing purposes should i just cap off the breather ports on the valve cover?
    p.s. ive eliminated all emisions from the car (removed) and for testing reasons ive capped off all vaccume ports on the i/m
     
  6. pissedoffsol

    pissedoffsol RETIRED

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    killing your vacuum system is NOT a good idea
     
  7. atari

    atari Junior Member

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    what exactly does that mean? im not running the car im just trying to narrow down a boost leak.
     
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