Plug replacements for O-360-A3A

Hey all... awhile back I posted querying on spark plug replacements, but I
have no actually looked at the plugs I currently have. I thought they were Champions,
but they're actually Auburn ER400 SR-88. From the chart he
http://tinyurl.com/arqcv (warning: PDF at lycoming)
those plugs should not be used in an O-360-A series engine. Presumably, that's
because it's high-compression, and the SR-88 is a hot plug. Strangely, apparently the
REM40E is the equivalent Champion plug, which *is* approved in the A-series.

I've pretty much decided to go with the Autolite plugs, but now the question
is which one. I run autogas (93 AKI) in it usually and have seen no ill effects from
the hot plugs and marginal octane rating save one: When returning from a flight on
autogas, if I try to shut down the engine with the mags, it will diesel. I was
worried until I checked a friend's Cherokee-150 with low-compression.... definately
NOT marginal for octane rating It dieseled under the same conditions.

So, I haven't had any fouling problems or any indication of detonation in
flight. I've looked at the pistons through the plug holes, and just a nice thing
carbony layer. Should I go with a colder plug, or put in the Autolite equiv of what's
in there (UREM40E)?

-Cory

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* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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