PADDY WILLMER wrote:
>
> Well, where are you all today? Bad week at work? I have just bought a
> new petrol pump for my TB, so it will be interesting to see if the
> diapraphm lasts.
Jerry Felper had a batch of diaphrams made up
of Viton, or some other extremely modern gasloine impervious stuff. His
company name is British Auto Electric.
One of the top hat rubber washers underneath a carb
> fell to pieces the other day, and it was only fitted last autumn.
Must have been old composition rubber. Rubber compositions changed (or
should have) between 1984 and 1987, for those applications where rubber
would be in contact with the modern reformulated gasolines. MTBE, placed
into unleaded gas to oxygenate it for lower emissions, is an ethyr. It's
best attribute is that it will clean the fuel system. Many fuel filters
have been plugged due to MTBE working so well in the fuel tank,
dissolving gum despoits, and sending microscopic particles past the fuel
filter screen, into the fuel lines, and into the carb float bowls. The
auto makers were made aware that this reformulated gas was going to hit
the market at some time in the near future, so they changed their rubber
hose specs to accomodate the change. Any rubber part that was made prior
to 1984-87 will probably harden and crack in a short amount of time
after exposed to these modern additives.
John Seim
The
> network of garages in the UK selling leaded petrol continues to grow,
> but one wonders how long it takes to sell 25,000,000 gallons of it, as
> that is all we get each year, and it is not rationed to, say pre-73
> cars that don`t pay road tax, so all old bangers as well as classic
> cars can buy it, and there are a lot of them about.
In the USA, unleaded gasoline has been the only available source since
1974. If you were driving a big block Detroit Iron muscle car, I would
worry about unleaded gasoline and pinking/detonation. I have a 1970
Ford, with a 351 ci engine, that states on the air cleaner requires 91
octane regular gas. Let me tell you, 92 octane premium barely works. The
octane rating of gasoline has decreased since the 70's. Additives have
been put into the gas to make up for the reduction of lead, and its
benefits. If you were always towing something with your car, or driving
hills under load, yes, you probably will experience valve seat recession
more rapidly than the rest of us. So, the next time you have the engine
torn down, have hardened seats installed in the head, and maybe go to
stellite valves. Unleaded gas, in itself, isn't a bad thing.
John Seim