John, you have hit on an interesting topic.
In a message dated 98-05-19 06:47:38 EDT, jonmac writes:
> Can anyone please tell me whether unleaded fuel was commonly available in
> the States in the 'sixties?
No, it was NOT commonly available. AMOCO's highest octane fuel (trade name
AMOCO Supreme) was unleaded and their ads made a big deal about it. The ads
touted the "cleaning" quality. The gas was clear in color rather than red
like most of the fuels of the day. I used to put in a tank of it every 4or 5
fill-ups. AMOCO was not the biggest company nor were all their fuels (usually
3 grades at the pump) unleaded. None of the other companies sold unleaded
fuel to the general public.
> 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?
Don' t think it suggests that at all. It was just a perception that things
were different in Europe. Since leaded fuel was considered "better" (remember
this was pre-environmental concern days) and WWII was still quite fresh in
everyone's memory, I think many Yanks felt they might be subjected to unleaded
fuel in Europe. The average consumer/driver didn't really know what the lead
did except that it was "better" and the engine didn't knock as much. They were
probably looking for reassurance that unleaded fuel would not harm the car
before it was shipped to the states.
Such being the case,
> does anyone have an original factory handbook which comments specifically
> on the type of fuel that was suitable for use?
I can't find any mention of leaded vs unleaded. What is mentioned is octane
rating. I know that my TR4 would not run on the lower octane fuels without
knocking (pinking - as you call it).
> 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.
I doubt that Coventry fitted hardened valve seats in the '60's. Leaded fuel
WAS the most common type of fuel in the States then. The only unleaded fuel
available at the highway side pump was AMOCO Supreme. Neither ESSO (EXXON for
you young ones), GULF, MOBILE, SHELL, TEXACO nor any others that I remember
sold unleaded fuel.
IMO - If the Spits have not suffered catastrophic damage it is probably
because running on unleaded is not as problematic as some "nervous-nellies"
think. The problem of leaded vs.unleaded has been completely blown out of
proportion. Running unleaded in a nonhardened valve seat engine will
EVENTUALLY lead to wear of the seats. In other words, the damned thing will
wear more quickly, not instantaneously. I think what we are seeing is proof
that damage is not going to happen immediately and has not ihappened n the
case of the Spits. BUT instead of using this fact to allay fears we go
looking for some other reason why the Spits have not blown up. The older
engines will run fine on non-leaded fuel.
[Having said that however, it makes sense that when the time comes for a valve
"rebuild" -- put in hardened seats as they'll last longer (relative term) than
if non-hardened were to be used.]
Art Kelly '64 TR4 CT33118L (original owner/factory pickup) driven around
Europe in '64 and then shipped to the US.
And Yes, I asked about unleaded fuel at Coventry on that morning of June 11,