<VV> 64 Engine in 65 / Oil leaks

[Andy Clark]

Hi Joel. Re your last question- try running a Corvair engine without an oil
cooler. I have never done this, but my OPINION is that it wouldn't last very
long because of rapid oil deterioration. Ergo, my statement that it is an
oil-cooled engine (should have said "partially", "mostly"? to be absolutely
and microscopically correct, as required).

In a nutshell, the tubes are conducting heat from the oil on their inside
surfaces. The outside color has little to do with that except that if the
tube is dissipating more heat outside, then the inside of the tube can
absorb more heat, faster. If the outer surface of the tube can be a made as
close as possible to a black body radiator, there will be maximum heat
transfer to the air flow. Hence the tubes can be made to cool the oil more
than they would with a natural finish. In fact, a rusty surface dissipates
more heat than a shiny one (I know, I know, the rust is somewhat of an
insulator, but there it is). Note that most of the cooling effect occurs at
the cooler block end of the tube, so that the recommendation to paint the
head end white may have some merit. I painted the whole tube black (did I
mention a LIGHT coat? <G>).

It's not intuitively obvious, especially as some whose opinions are highly
valued in the Corvair community have recommended a white finish for the
entire tube. However my oil temps came down about 10 degrees on average in
very similar before/after ambient temps at the same track, although a week
apart.

As always, YMMV.

Andy Clark
Camano Island, WA.
1966 140/4 Monza Sedan
1966 140/4 Yenko Clone
1966 180/4 Cord 8/10 #60

----- Original Message ----- 
From: "Western Canada CORSA" <westerncanadacorsa at shaw.ca>
To: "'Andy Clark'" <slowboat at mindspring.com>; "'VV'"
<virtualvairs at corvair.org>
Sent: Saturday, March 24, 2007 4:13 PM
Subject: RE: <VV> 64 Engine in 65 / Oil leaks


Andy,

So what you're saying is that the black absorbs more heat out of the oil in
the pushrod tubes than it absorbs from the exhaust logs below it?  And it
can then expell that heat in the passing air more efficiently?

Does the oil actually do that much cooling in a 'vair engine?  I thought
that was a Porsche thing?

Regards,
Joel

-----Original Message-----
From: virtualvairs-bounces at corvair.org
[mailto:virtualvairs-bounces at corvair.org] On Behalf Of Andy Clark
Sent: Saturday, March 24, 2007 6:07 PM
To: VV
Subject: Re: <VV> 64 Engine in 65 / Oil leaks


Yes, true about adsorption, but the airflow is down, away from the manifold.
My tests indicated that any radiated heat from the exhaust manifolds is
small compared to the conducted heat carried by the air from the tubes, and
has little, if any, effect. The upshot is that the oil temp is reduced by a
light light coat of BBQ black on the tubes. Remember that the Corvair engine
is really oil cooled, so any additional heat taken from the oil in the tubes
helps.

As always, YMMV.

Andy Clark
Camano Island, WA.
1966 140/4 Monza Sedan
1966 140/4 Yenko Clone
1966 180/4 Cord 8/10 #60
----- Original Message ----- 
From: "Harry Yarnell" <hyarnell1 at earthlink.net>
To: "Andy Clark" <slowboat at mindspring.com>; <westerncanadacorsa at shaw.ca>;
<VirtualVairs at corvair.org>
Sent: Saturday, March 24, 2007 3:40 PM
Subject: Re: <VV> 64 Engine in 65 / Oil leaks


> Yea, but isn't black the best at absorbing heat? Like the exhaust
> manifold right under them?
>
> harry yarnell
> perryman garage and orphanage
> hyarnell1 at earthlink.net
> ----- Original Message -----
> From: "Andy Clark" <slowboat at mindspring.com>
> To: <westerncanadacorsa at shaw.ca>; <VirtualVairs at corvair.org>
> Sent: Saturday, March 24, 2007 6:32 PM
> Subject: Re: <VV> 64 Engine in 65 / Oil leaks
>
>
> > Joel, it's the "black body radiator" theory. The coating (remember,
> > I
said
> > LIGHT...maybe I should have said VERY LIGHT), increases the
> > emissivity more than it increases the insulation.
> >
> > Andy Clark
> > Camano Island, WA.
> > 1966 140/4 Monza Sedan
> > 1966 140/4 Yenko Clone
> > 1966 180/4 Cord 8/10 #60