[urq] Too much Crankcase ventalation?

Ado Sigal a.sigal at bluewin.ch
Wed Sep 5 14:48:58 EDT 2007

Hi Ben

On atmo engines, the connection between valve cover/crancase and IM is 
always done with metered orifice PCV, as there is no pressure in the IM. 
Turbo engines use PCV check valve, in order to prevent pressure been 
created in the crankcase. The other hose on Urq and other is not metered 
and always goes to no pressure side (before the throttle body). In your 
case, instead to the igloo, it can go anywhere suitable in the atmo side 
of the intake, or be released into the atmo via filter, or into the 
catch can with filter to the atmo. It seems that you need to insert the 
PCV check valve into the IM/v.cover hose, and mount the filter on the 
other hose and release it underbonnet into the atmo for the moment, and 
go from there.

I am doing this with CIS, since it was found that there is no 
condensation gunk or oil coming out of it, probably because its so hot 
on EM side of the motor and oil always gets hot. On the other hand, I 
used catch can on 5L atmo Passat that has crankcase and v/cover 
connected via metal pipe, and have to drain it on regular bases. What 
cones out of the c/can is smelly water and few drops of oil, and one 
would not want to return this into the crankcase again. In your case, 
the oil escape or condensation shouldn't be an issue with no pressure in 
the crankcase, good engine and hot oil. However, if you want to improve 
on the issue, you can try to fit the plastic splash cover used on 4 cyl 
VW engines. Never tried it, but the VW  4 pot uses very similar head 
design, so the splash cover could be made to fit, me thinks. Seen one on 
Transporter recently.

HTH, Ado

Ben Swann wrote:

>The engine installed in '83 Ur Quattro >>>
>OK - back to the XS crankcase/camcover vent issue - this is surely what it is,
>and Scott helped bring it to light with his questions.  I'd rather not design
>and implement a catch-can system yet although it is something possibly to
>consider if I push boost over 2.5 bar.   I would like to know how I can
>regulate things so it just isn't trying to suck the outside in at idle or blow
>insides out at full boost - slated to be 2.5 in the near future, but need to
>do basic tuning first.
>In answer to Scotts ?'s below re. how it is plumbed, it seems I my have things
>a bit too simplified right now and I would not even consider present hookup to
>be "PVC".  Basically there is direct connection using a stock hose between cam
>cover, intake manifold and crankcase.  So I surmise that whatever manifold
>pressure is, it is the same inside the camcover, and crankcase as well.  Big
>oversight I suppose or more like, just getting things to work as they should
>after the car has been down for nearly a year.
>Catch can recovery system is not outside the question of future mods, but
>certainly outside the scope for the immediate needs as best as I can tell.
>TIA for suggestions even on how to make a simple catch can and drainback.  

More information about the urq mailing list