<VV> CHT Re: valve seats and "Ping"

[FrankCB at aol.com]

Matt and John,
     Some decades ago when I drove my 1965 180  regularly to work, it would 
NORMALLY run at 400 deg.F (stock gauge  and thermistor) on level highways 
at 55 to 70 mph.  Occasionally  I would "floor it" going up a long hill to 
see what boost I got and the stock  CHT would go to 450 deg.F. but I did have 
a electronic knock eliminator (Carter  EKE) which may have saved me.  The 
boost reached 8 psig on a non stock  gauge.  It was only after I insulated the 
exhaust piping UPSTREAM of the  turbo that I was able to get 10 psig.  But 
the stock exhaust piping lasted  only about 6 months before it disintegrated 
at the UP-bend due to overheating of  the metal (according to the chief 
metallurgist at the chemical plant where I  worked).
     My other Corvairs (110 and 95 hp models) I ran  with an aftermarket 
CHT gauge installed.  This was a Stewart Warner  "Corvair Cylinder Head 
Temperature Gauge" (Model 366-LW) with a gauge that ran  from an indicated 200 to 
500 deg.F. and included a thermistor that was installed  in the STOCK 3/8 
in. tapped hole in the "forward portion of the left cylinder  head".  I 
checked the calibration of the gauge in boiling water and it was  right on using 
14 volts.  In operation both the 110 and 95 hp engines  normally indicated 
350 deg. F.  Except for the two times when I let it get  up to 450.  One time 
I had to drive home on only 3 cylinders due to only  one functioning carb 
fortunately on the left bank.  The other time I had to  drive home local roads 
with NO functioning fan due to harmonic balancer  separation.  Both times 
when the temp got over 450, I stopped for a time  and let the engine cool off 
before resuming my trip.  Both times the engine  suffered no apparent 
damage, but it did have the advantage of synthetic engine  oil and Viton O-rings.
     That's why I believe EVERY Corvair needs at least  ONE CHT gauge.
Frank "likes gauges" Burkhard
Boonton, NJ
 
 
In a message dated 5/10/2012 4:08:22 P.M. Eastern Daylight Time,  
patiomatt at aol.com writes:




OK, after some reflection, that may be a bit too  conservative. I do know, 
once 
CHT reaches 400F or more, detonation and  preignition become a LOT more 
prevalent 
here. And no doubt, all that  knocking will beat on things in a way that 
not only 
kills power, but  engine parts as well, and seats come to mind...

John  Roberts

=========================================================


My exact  beliefs!  When in SoCal I did everything possible to keep  from 
pinging...keep the heads near 300F.


No that I'm on the Oregon  coast I find I can run the 400f for 
efficiency....  and not  rattle!


I've only lost 3 seats in my life.


Matt  Nall
Charleston,  Oregon
http://tinyurl.com/The-Patio
http://tinyurl.com/Matts-Tech-Pages











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