<VV> Oil pushing up dipstick tube

[Brown, David]

I had this problem with both my 65/110 & my 69/140.  Both were
documented 'tired' engines with unknown mileage.  The 110 never really
showed 'bad' compression (the lowest was 90 minimum to 110psi, hot & wet
[gas applied during check]).  As long as I kept it under 3,500 rpm, it
wasn't too bad.  The engine would look like I left the oil cap off if I
ran hard above 3,500.  It otherwise ran perfect & averaged about 24mpg.
I relieved the pressure problem by running an additional homemade vent
tube from the oil cap to a collection reservoir (plastic aftermarket
radiator overflow chamber) & from there to the backside (front) of the
air cleaner.  Any oil residue would get blocked in the plastic chamber
(by some 3M scrub pads I stuffed inside it) & eventually drain back into
the engine via the oil cap.  'Bad' air would continue through to the air
cleaner to be re-burned.  This way I could take it above 3,500 for short
bursts w/o worrying about a mess coming back through the dip stick.  It
stayed this way for several years till the day I sold the engine.  Upon
rebuild the new owner told me the rings were intact, so I just assume
there was enough wear to allow the blow-by & back pressure to build up.

The 140 was a different story.  It happened before I figured out the
reservoir deal & progressed more rapidly than my 110.  I also kept it
under about 3,500 to prevent a mess, but one day, while warming up &
idling, it suddenly switched from building up crankcase pressure to
pushing right past the piston to the exhaust.  While watching the engine
warm up, I was surprised to suddenly see smoke coming out of the right
exhaust only.  I pulled the head to find exactly what I expected- broken
rings.

I have since heard a dozen similar stories of the blow-by (crankcase
pressure) problem where the owner drove the car for an extended time. I
like the reservoir 'fix' to help relieve the pressure build up & recycle
the bad air, if one does not want to do a rebuild right away.

Dave
Corvar Houston

**********************************************
-----Original Message-----
From: virtualvairs-bounces at corvair.org- On Behalf Of Kinzelman, Andy
Subject: Re: <VV> Oil pushing up dipstick tube

My daughter's 65 Monza just started pushing oil up the  dipstick tube.
I looked at the tech guide & 'The Classic Corvair';  but see no mention
of it.  I presume (if the rings haven't suddenly worn  out) that she has
a plugged breather tube and/or orifice on vacuum balance  tube.  Could
it be anything else?
Thanks, & Merry Christmas,
Andy K.

**********************************************
-----Original Message-----
From: virtualvairs-bounces at corvair.org
Subject: Re: <VV> Oil pushing up dipstick tube

Mine does the same thing after a while if I block the breather but are
really two issues:
1) why is the crankcase becoming pressurized
2) why is the pressure not being relieved.

First thing to do is to run a compression check. This will tell you if a
cylinder may be causing the problem. In my case the compression is fine
and I am suspecting worn valve guides.

Oriface is only 5/64" and does not flow much even when operating
properly.

Padgett