[urq] Too much Crankcase ventalation?

Claus Vegener vegener at post7.tele.dk
Wed Sep 5 15:00:44 EDT 2007


Dave - I am not happy to hear, that you have those problems with an AAN, 
where the valve cover do have a return drain to the crankcase with the hole in the block 
at back cold side.and from there down under the PCV goes up to a breather can.
I don't have the hole and made one in the 3B pan (so that what that funny flaps are for).
I have placed an outlet at the top of the valve cover - but should have been more in the front close to the filler cap,
 where there is some room to weld a drain plate under the outlet to the separator and catchtank.

But Scott: The reason for not running the ventilation back to the inlet and using vacuum to do that
is also, that the octane number decreases with oil mist. 
I have heard about a vacuum pump to make vacuum inside the engine; but I think it only moves the problem and
need a drain to the pan too.
Claus
  ----- Original Message ----- 
  From: QSHIPQ at aol.com 
  To: Djdawson2 at aol.com ; vegener at post7.tele.dk ; quattro at audifans.com ; urq at audifans.com 
  Cc: benswann at comcast.net 
  Sent: Wednesday, September 05, 2007 6:49 PM
  Subject: Re: [urq] Too much Crankcase ventalation?


  Gents
  I think there are some misunderstandings of how PCV works, and the risks and benefits of a variable PCV valve closed loop system.  If I were looking to modify PCV to be properly routed, the nicely designed ball valve used in the toyota supra turbos is where I'd start my search.  For a good introduction into how that valve works and some of the issues, take a gander thru this pdf...

  http://www.autoshop101.com/forms/h63.pdf

  I used this information as a guideline for PCV reroute and modification on my supercharger addition to my landcruiser

  HTH

  Scott Justusson
  In a message dated 9/5/2007 10:35:40 A.M. Central Daylight Time, Djdawson2 writes:
    Claus,
    This is the same experience I've had.  Mine is a '93 UrS4 with an AAN, and runs in the lower 12 second range as well.  Upon launch, oil goes everywhere... typically 1/2 quart pushed out the breather on each run.  The car isn't geared appropriately for the 1/4 mile, so I end up going through the traps at over 8000 rpm.

    During daily use, this is not ever an issue... but very annoying during a hard launch on the street or track.

    Dave






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