Fred,
It seems the situation may be a bit different in the US to Europe. From
the time leaded fuel was introduced for road vehicles in the '20s, only
leaded fuel was available, until the mid 80's when unleaded was
re-introduced for environmental reasons. Because of this, most European
engines were designed with the expectation that their valve seats would
be protected by lead, and most engines had the valves seating directly
into the cast iron head, rather than having hardened inserts fitted.
The biggest exception I am aware of is the Rover V8 unit (as used also
in the Triumph TR8, MG BGT V8, Morgan +8, many TVRs and Marcos', Range
Rover etc.), which was based on a Buick engine.
Valve seat recession due to the use of unleaded petrol is a
well-recorded phenomenon, both in everyday use and in tests such as the
one performed by the FBHVC. Their tests were carried out on an Austin
A-series engine, one particularly vulnerable to this phenomenon, which
was used in the Austin-Healey Sprite and MG Midget (as well as Austin
A30, Morris Minor, Mini, Austin Metro etc.).
For American cars, then, I guess unleaded is fine if you say so.
However, for cars of British origin, unless powered by the Rover V8, it
is best to assume they were designed with leaded petrol in mind, and
unleaded petrol should be used with suitable additives, or a cylinder
head conversion, if you do not want to risk damage, or erosion of power
due to loss of compression ratio.
Richard Gosling
Daffy (Inca yellow '78 Spit 1500)
Fred Thomas wrote:
>
> Richard, unleaded gas has been around and in dailey use since the 1920's,
> the gas has been reformulated for todays and yesterdays engines, all this
> worry about unleaded is also unfounded, 80 years of use prove that. If you
> remember "Amoco has always been unleaded, all marine petrol has been
> white/unleaded since the 1930's, and marine engine are also auto engines,
> there were no hardened valve seats in the 1930 to 1970 autos, so why all the
> worry now. You will also find just as many reports telling you how harmful
> leaded fuel is for auto engines. Sorry, yes you may have to reset the
> timing, but, I doubt it. "FT"
> ----- Original Message -----
> From: Richard Gosling <rbgos@perkins-engines.com>
> To: <spitfires@autox.team.net>
> Sent: Tuesday, December 07, 1999 5:05 AM
> Subject: Re: No leaded fuel. What to do?
>
> >
> > Jeff,
> >
> > In the UK we are going through the trauma of the withdrawal from sale of
> > leaded fuel right now, so there is a lot of discussion and information
> > going around about what to do.
> >
> > Basically there seem to be 3 options:
> >
> > 1. Just put unleaded in your tank, and retard the timing a little to
> > avoid pinking. After many years of running on leaded there will be an
> > amount of lead absorbed into the surface of the metal, and this will
> > provide limited protection against valve recession (the real killer with
> > unleaded fuel in cars not designed for it). This may be sufficient if
> > you do low mileage, and drive gently (neither of which I would advocate,
> > as someone who does 16,000 hard miles a year in my Spit 1500!), but
> > eventually the valve seats will wear and you will have to have your
> > cylinder head re-conditioned and new valve seats and valves fitted.
> >
> > 2. Get your cylinder head converted right away, rather than waiting for
> > the damage to occur and then getting it done - best option for the long
> > term, and not too expensive (at least in the UK, no idea about the US).
> >
> > 3. Use an additive in your unleaded petrol. These are available in car
> > part stores in the UK, and presumably in the US, plus we get it
> > available pre-mixed in what is called LRP (lead replacement petrol) at
> > the pumps - not a conveniance you will have! The additive is simply a
> > small bottle, add one to your tank each time you fill up, and it
> > contains a (non-lead) chemical that gives similar protection to lead,
> > although not quite as good. Some also contain an octane booster, so you
> > do not even need to retard your ignition.
> >
> > The FBHVC (Federation of British Historic Vehicle Clubs), an umbrella
> > organisation for all classic car clubs in the UK, did tests on around 12
> > different additives at the beginning of this year, and found just 4 that
> > they could recommend - if you want to know which these are I can dig out
> > the info.
> >
> > Beware of anyone trying to sell you any sort of 'catalyst' or device
> > that you fit in the fuel line, ususally containing tin pellets, that
> > claim to allow you to use unleaded fuel with no problems - the FBHVC
> > tested several of these and could not recommend any of these.
> > Personally I doubt these are anything more than a placebo.
> >
> >
> > I hope this helps, and doesn't just make the issue more clouded!
> >
> > Richard Gosling
> > Daffy (Inca yellow '78 Spit 1500)
> >
|