<VV> heating the oil

[Robert Coffin]

Hi Bob ,
You wrote :
<Now it may very well also lower the heating of the oil, but how do you
know?
This is really not a proven factor. But if I am wrong, then please show me
the
data.>

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 a
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