Mark Writing here:
"Combustion processes did NOT change by act of Congress"
(or act of Parliament for the UK readers)
Don't worry about lead or it's lack. The only thing you really have to
worry about is that you have a fuel of sufficient octane to prevent
detonation.
Tetraethyl lead was added to motor fuels in the 40's as a cheap octane
booster. It's "Valve lubricating' properties are largely myth. In fact it's
introduction led to far more problems with fouled spark plugs and nasty
deposits on the valve stems than supposed lubrication.
Any brand of modern fuel will be fine They all have sufficient "valve
lube" additives to stop the dreaded ' valve seat recession'. There may
(MAY!) have been some minor problems with the first blends of unleaded sold
in the US in 1974, but compared to all of the other mitigating factors
(drivers suddenly stuck with engines half the size they were used to et c.)
even that is questionable.
The quotes there are from personal experience and frustration at the
subject recurring. ( I gave up on my UK friends with their unleaded scare
last year) and having run any number of miles with plain iron heads and
unleaded and never having had any noticable effect. My first Cortina was run
very hard indeed and tinkered with unmercifully. If there were any problems
with valves I certainly would have noticed.
Going to specific examples - EVERY engine with aluminium heads ALREADY has
the 'Hardened Valve Seats" so loved by machine shops out to make an extra
buck on the gullible. There's no other way of doing it really given the metal
choices available du to the differning coefficients of expansion for putting
a seperate valve seat in in the first place.
If it makes you feel good to pour extra stuff in your tank, go ahead. But
for all the necessity and advantages of doing so you could just give the
money you spend to the next homeless person you see. Either way you'll get
a feeling of accomplishemnt without doing much.
Mark not
Laurie :-)
70 SPL311
69 SRL311
Chandler, AZ
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