<VV> Corvair a City Car / make it a Highway car

[Brown, David]

Hi Brent,
I'm still not sure I understand EGR, but I did a similar thing to
relieve crankcase pressure on my tired 65 110.  I attached a cheap after
market radiator overflow tank (see attached picture- VV will delete, so
anyone besides Brent, let me know & I will forward the picture) with a
hose from the oil cap & another going back into the back side of the air
cleaner to re-burn the oil laden gases.  In the reservoir tank I stuffed
several pieces of 3M scrub pads so any heavy residue would be captured &
eventually drain back into the oil cap.  This was enough to totally
relieve the crankcase pressure (& dipstick oil emission) as long as I
didn't go flat out & red line it.  The engine ran beautifully for the
next 3 years, getting 24MPG, until I finally was in a position to pull
it (last year) so I can install a new 140 (this month?).  I think as
long as the blow-by is staying in the engine & not coming out the
exhaust, this is a great way to prolong the engine life.
Dave
Corvair Houston 

-----Original Message-----
From: virtualvairs-bounces at corvair.org
[mailto:virtualvairs-bounces at corvair.org] On Behalf Of Brent Covey
Sent: Tuesday, May 09, 2006 2:49 AM
To: virtualvairs at corvair.org
Subject: Re: <VV> Corvair a City Car / make it a Highway car

The idea of Exhaust Gas Recirculation sounds good to me-

I have nursed a few extra miles out of old garbage 110's in what
amounted to parts cars with bad compression rings and tapered cyl
barrels (pays to have working thermostats!) that were doing that oil
squirt thing out the dipstick tube by plumbing the PCV foo-foo tube with
a normal PCV valve directly into the balance tube. This was done on
engines in really appalling condition, that could not have been driven
without oil ejecting out the dipstick otherwise. There did not seem to
be any negative effects from doing this, although I imagine the crank
seal surfaces might be damaged, and that crankcase ventilation wasnt all
it could be... This subjects the crankcase to manifold vacuum under all
conditions, which isnt entirely desireable but has some interesting side
effects-

#1- No more oil leaks with a running engine!

#2- Free 'EGR' and idle stabilization

#3- Oil consumption dropped to practically zero even on engines with
very weak compression.

It was usually neccesary to make a loop of hose in the PCV plumbing that
reached high up by the plenum to preclude oil condensates from being
drawn into the PCV.

The blowby is essentially wet steam with a bunch of inert post
combustion gasses that works a lot like water injection. Because the
volume of blowby is proportional to engine load, under load or at idle
you get more than usual. This allows a little extra tolerance before
ping under heavy throttle, and tends to even out idle when a/c
compressors are switching on and off etc.

Although I wouldnt suggest this modification on an engine in good
condition, it kept a few old beaters running an extra year or two and
demonstrated the effectiveness of EGR on a Corvair to my satisfaction.
Economy with these engines was very good, although whether it was lower
throttling losses or just the lack of friction from the absence of close
tolerance parts I cannot say. I would regularly see mileage in the 26-27
USmpg zone around 55-60 mph on premium gas.

A proper EGR system might be a pretty good thing from a fuel economy
perspective, some of the ~1975 model GM cars (Pontiac) has a EGR signal
amplifier built in that could likely be adapted to operate the Corvair
system if you tapped an EGR port into the exhaust system. I would
imagine the balance tube should be rerouted on the drivers side to enter
under the LH primary carb for best effect on 140's.

Brent Covey
Vancouver BC
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