Re: [T3] Oil forced out of breather

["Dave Hall" <dave@hallvw.clara.co.uk>]

Didn't someone say the 72/3 connects to the air-cleaner suction, not atmospheric
pressure?

If reduced crankcase pressure prevents oil being expelled from the breather,
increasing the pressure to atmospheric would encourage an airflow through to the
breather and air cleaner, which might lead to it picking up oil on its way
through the narrower breather channels.  Also, the cool air would expand a bit
too when warmed by the engine.

Dave.
UK VW Type 3 & 4 Club
http://www.hallvw.clara.co.uk/
------
----- Original Message ----- 
From: "Jim Adney" <jadney@vwtype3.org>
To: <type3@vwtype3.org>
Sent: Tuesday, May 04, 2004 5:22 AM
Subject: Re: [T3] Oil forced out of breather


> On 3 May 2004 at 23:53, Dave Hall wrote:
>
> > VW Workshop bulletin M-5 August 1969 for Types 1, 2, 3, and industrial
engines
> > 122, 124A and 126A states:-
> > "If oil is lost via the crankcase breather, first check whether the cylinder
> > head cover gasket is properly located, as tests have shown the following:
> >
> > Increased pressure in the crankcase causes oil to be forced out of the
crankcase
> > breather on some engines.  The cause of the increase in pressure can be due
to
> > gaskets that slipped.
>
> I wonder if this could be because of the way the opposed pistons always move
in
> opposite directions and that the main bearing webs divide the case into 3
> chambers. There is space above the webs, but maybe that's not enough to keep
> things on an even keel. This might mean that the pressures/vacuums built up in
> there might not even out and there might be some net pumping.
>
> But if that's the case, why don't the 72-3 engine have this problem, even
> though they have vents in the rocker boxes?
>
> -- 
> *******************************
> Jim Adney, jadney@vwtype3.org
> Madison, Wisconsin, USA
> *******************************

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