>I've been following this GT6 overheating thread since it's beginnings - with
>interest - this latest reply sounds very convincing - if the head indeed has
>an inherent hot spot in it around the plug holes, couldn't a "hot plug"
cause
>overheating? Coincidently, wouldn't it cause pinging or possibly run-on?
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I wrote a reply to this, which you may not have seen. To dispel this idea,
the heads used for the TR6 are identical with the GT, save for a thicker
deck (lower compression) and they don't have any tendency to overheat even
with the increase in engine capacity and resultant higher thermal load
impose on that engine.
Number 2. The area of the plug That is actually heated by combustion is
VERY small indeed, compared to the REST of the chamber area, and any heat
carried by the insulated portion of the plug would be QUICKLY dissipated
and of almost no consequence as far as total combustion chamber heat
transfer.
Number 3.
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>couldn't a "hot plug" cause overheating?
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No, even arguing for the moment, that the plug could transfer enough heat
to effectively make any difference, a hotter plug by it's very nature
retains MORE heat in the insulator (hence the term hotter plug) and doesn't
transfer it into the head to be dissipated by the coolant, or cooling
system. Therefore, for this hypothetical answer, it would (if it could)
actually cause the engine to run cooler.
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Coincidently, wouldn't it cause pinging or possibly run-on?
**************************
Yes, in actuality it most likely will cause these conditions in an already
hot running engine and if the heat range were increased too much, possibly
melted electrodes-
Barry Schwartz (San Diego) bschwart@pacbell.net
72 PI, V6 Spitfire (daily driver)
70 GT6+ (when I don't drive the Spit)
70 Spitfire (long term project)
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