[T3] cylinder head breather ports on a 1972 Squareback

[Dave Pallo]

[[[Without fresh air getting into the case, there will be a bit of a vacuum
in his case, much of which will be alleviated by blowby and vapor from any
gas in the oil. This should not cause any problems.]]]
 
My '72 with its PCV system intact draws what I would call a "fair" amount of
air from the crankcase. If I were to plug the ports on the heads - the
vacuum draw would pull air in from somewhere. I know blowby would make a
contribution by adding air into the case, but I think there would still be a
need for more air into the crankcase than that (especially on a new motor),
and I would bet the easiest place for the crankcase to draw in air would be
around the crankshaft behind the fan, where there is no seal, and this would
be unfiltered air being drawn into the crankcase. When VW used the heads
with breather ports made just for a PCV equipped motor - these are not small
ports ( about .5" diameter X 2), and they made sure the air entering these
ports was filtered air by running hoses up to the air cleaner. In my
opinion, if anyone was running an intact pcv equipped system - they should
have a way to allow filtered air into the crankcase, just as they did at the
factory. Jacob mentioned valve covers with breather ports in them. I've
never seen them myself, but if they have a way to allow air in - and filter
it - I would consider using them since he doesn't have the heads with the
ports. Just my 2 cents...
 

 

Dave Pallo

'72 Square ~ Elwood

Fairport, NY

 

 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.vwtype3.org/pipermail/type3-vwtype3.org/attachments/20130805/76350118/attachment.htm>