<VV> Re: VirtualVairs digest, Vol 1 #1736 - 8 msgs

[kenfran at comcast.net]

I know it will probably be viewed as a wild idea, but I think that the ideal
solution would be to eliminate the pushrod tubes, the pushrods, the cam, the
rocker arms, and the tappet valves, and convince the patent-holder on the
Coates rotary valves to produce a rotary-valve head for the Corvair, or at
least allow his patents to be used to help publicize his technology..
http://www.coatesengine.com/photo_gallery.html

> While I think the quantity of oil coming from the head area to the block
on a street car is minimal , keeping the  radiant and convective heat from
the exhaust pipe/ manifold away from the pushrod tubes, and the oil therein,
is justified.
> This is from the point that any temperature over 350 degrees will break
down the oil into varnish products , decreasing the lubricity and life of
the oil.This condition certainly can exist in the pushrod tube near the
exhaust tube.Especially on Turbo engines.
> Also, for a race application , where higher temperatures are involved at
both the exhaust port [1250-1300 degrees] the oil in the tube is subjected
to even higher temperatures for a longer period of time making the problem
worse for the oil.
> And, sometimes, head temperature[and the air coming from them] is close to
400 degrees, further aggravating the situation.
> Add cornering forces that push large quantity of oil back and forth
through the tubes , and it becomes obvious why racing Corvairs need extra
oil cooling capacity to maintain proper oil operating temperatures.
> Finally , on my race engines , I have seen a measurable oil temperature
reduction by coating the outside of the pushrod tubes with red high
temperature RTV silicone rubber on at least the outer 1/2 of the tubes, as
an insulating medium.
> I did this in the late seventies when I was racing my D/Production Yenko
Stinger , and on most performance engines I have built since then. I would
recommend doing it routinely on any High Performance Corvair Engine.
> Bob Coffin