John writes...
>Can anyone please tell me whether unleaded fuel was commonly available in
>the States in the 'sixties?
As you've already read, "Unleaded Amoco" was available here through
the '60 and perhaps before that. It was marketed as a cleaner burning
fuel for the benefit of the engine, in particular to extend plug life.
It was not marketed as having any positive effect on the environment.
That idea was not "in" yet. It was sold based on it's performance at
a time when green stamps, free tumblers and "platformate" were all
used to entice customers to switch brands. You guys *did* get your
share of "platformate" over there, right? Uh...nevermind. :-)
I wonder though if unleaded Amoco was 100% lead free or if there were
trace amounts left in to protect the valves...dunno. At any rate I
never read *anything* about the product that would suggest it's use
would promote valve recession. It was not our top selling brand by a
long stretch, but it sold well enough to give an excellent field test
for cars of that vintage.
>I remember many people who were taking delivery of their cars in the UK
>asking whether they should use leaded or unleaded while in Europe. This
>suggests it was fairly freely available on t'other side, while still being
>effectively unknown in Europe at the point of sale? Such being the case,
>does anyone have an original factory handbook which comments specifically
>on the type of fuel that was suitable for use?
>Unleaded certainly was not on sale in the UK at that time, though the car
>manufacturers did have special supplies of their own. It occurs to me from
>a discussion I had with someone yesterday, that if unleaded was commonly
>found in the US, there's just a chance that Coventry fitted hardened valve
>seats as a matter of course to many engines prior to 1968. I greatly doubt
>they'd have had a US head and an Everywhere Else head going through the
>engine build shop. If they did fit seats suitable for green fuel, this may
>go some way to explaining why it appears so many Spitfire owners are
>running cars with 'old' type seats that don't appear to have suffered with
>green going in the tanks.
>
>John Macartney
I'm curious about the later Spits, in particular the 1500s. <see sig>
In the U.S., 1975 was the year that *most* new vehicles were equipped
with CATs and required unleaded fuel. There were a few exceptions,
mostly imports. Chrysler had some exemptions in 1976 on models
equipped with their new "lean burn" engine, but by '77 *all* new cars
sold in the U.S. had CATs and required unleaded fuel. AFAIK.
I note that the intake valves used in the Spitfire 1500 head changed
from the years 1974 to 1975. The later one is smaller according to my
infallible Vicky Brit catalog. :-) I was speculating that the smaller
valve might have had some connection to a change in head design that
would facilitate running unleaded fuel. Or it might have been
emissions related. I realise that you didn't see 1500 production
until 1975 but I wonder if the UK version also got the smaller valve.
Any data?
Cheers!
Tom O'Malley in Southbridge Massachusetts
'74, '77 Spits
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