Date:         Thu, 3 Dec 2009 02:50:26 -0500
Reply-To:     Sam Payne <bungeegull@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Sam Payne <bungeegull@HOTMAIL.COM>
Subject:      Re: info needed on crancase ventilation systems (mostly I4)

Neil,

       Thanks very much for the info. My original Audi motor didn't have a
pcv valve that I could find, the Bentley manual for it has no info, and
Audi 80's are like hen's teeth in the yards near here, so it's hard to get
a good look in the flesh at the original engine, BUT....
    The larger problem is which system should be considered 'original'
anyhow? I'm using an Audi engine run by NOT it's stock CIS injection
system, but by a pulsed injection system (LH Jetronic 2.4) taken off a
Saab. So I'm not sure what venting system to use: the original Audi engine
vent design, the fuel injection system I modified it with (from a Saab),
or the vent system on VW's like yours.
    I would prefer to use the VW system, actually, because it's simpler
for my intake plumbing, and the VW pcv valve will help reduce oil buildup
in the intake--I cut one open and the valve also serves as an air/oil
separator, because the input from the valve cover drains back into the
cover, while the output sticks up from inside the chamber like a raised
drainpipe, meaning oil droplets which swirl around in the valve and stick
to the walls etc. will drain back into the engine. Hard to describe.
   On the other hand I wonder if I should use the Saab vent system, since
all vented gasses in that system have already been measured by the air
mass meter, and the vented gasses probably matter more to the FI system
operation than to the engine.
   Or do engine venting requirements vary a lot from engine to engine,
meaning I should stick with the stock engine system.
   Gack. I'm probably being overcautious but I'm also curious about how it
all works. Why does the VW vent system have no fresh air intake? Why does
the Saab system have no PCV valve? Which is better?
   Maybe I have to bug Frank again.
   Anyway, thanks for your help again, and any more info will be welcome!

     Sam