I was reading a PDF copy of the British Leyland Motor Inc., service
division, dealer training booklet, concerning 1970 emissions data and on
page 7, it states:
To conform with the emission control standards, imposed by the federal
authorities, the following engine modifications are incorporated.
1. Exhaust Valves
Stellite faced exhaust valves are fitted to maintain effective valve
seating between servicing intervals.
< snip >
What this means for those of you with 1970 and later vehicles is that you
needn't worry about using unleaded fuel in your vehicle. From what I
remember (which is becoming cloudier with age :-}) this is one of those
changes made to preclude valve wear when unleaded was introduced. Stellite
(trademark) for those of you who might be interested, is a cobalt-base
alloy with chromium and other metals; very hard; used to make cutting tools
and for surfaces subject to heavy wear
I seriously doubt that heads destined only for the USA were the only ones
fitted with these valves, as I imagine the logistics of determining which
heads/engines are destined for what country would be more expensive than
fitting them to all cars. And I'm sure hardened seats would also be
fitted, as what would be the point of fitting harder valves just to let the
valves beat the seat to pieces, although I could be mistaken here
Just thought that might clear up a few things (or maybe muddy the waters
even more ;-0 ??)
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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