This is what Bob has to say about UnLeaded and Valves:
"Another common fallacy is that stellite valve seats are necessary for use
with unleaded gas. Think of it this way: your engine has run for the last
17+ years on unleaded fuel with cast iron or steel seats, even the late
Spitfires and MGBs which were designed to run on unleaded fuel. Steel seats
are far stronger than cast iron but much less expensive and damaging than
stellite, which are much harder than steel seats and accelerate wear on the
valve face. Stellite seats were developed by the automotive industry so
they could increase efficiency and gas mileage of their engines by running
them at designed temperatures of 205-215 degrees F. If your British engine
is run that hot for long, worn valve seats will be the least of your
problems. The primary problem with unleaded gas in British engines is the
lack of octane which can be compensated for by lowering the compression
ratio or retarding the ignition timing by a few degrees"
Tom Howard
'72 GT6 (and a good bit of USA iron)
Lakeside Union School District
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