<VV> lead additive

[Bill Elliott]

Actually, while that may be true for certain understressed American 
V8's, it's not a valid blanket statement. Some cars exhibit quick and 
severe valve seat recession (a late model UK car I had even announcing 
in the owners manual in huge red letters "Under NO CIRCUMSTANCES should 
this vehicle EVER be operated on unleaded petrol".)

The engine in many street LBC's is stressed to a level found only in 
racing versions of many American engines. A big block in the same state 
of tune as the nearly stock 1275 Mini would be putting out about 550 
(net) hp... or well over 600 in the old gross terms.

I have a big lazy Olds 455 convertible which "needs" leaded fuel but 
which I don't lose any sleep over operating it on high octane unleaded. 
On the other hand, my Mini (with a slightly warmed up  A+-series) gets 
the real stuff... the fact that it gets about 4 times the mileage of the 
Olds makes this a less painful practice.

I have run leaded fuel in my race Corvair, but only because that was the 
only local way I had to get enough octane. In Corvairs, lead is a bad 
thing (except for the octane) and should be avoided if at all possible.

Bill

>cast iron seats.<
>--------------------------------
>
>Many years ago Buick did extensive testing regarding the use of unleaded fuel
>causing recession of the valves in a cast iron cylinder head.  Their tests included
>hundreds of hours of normal to hard use simulation on dynamometers.
>
>Someone there wrote an SAE paper (sorry I can't find my copy) that showed there
>was no problem with recessing of valves until after many, many hours of hard racing.
>They concluded there would be no noticeable problem associated with unleaded gas
>use in street driven cars as long as the engine octane requirements were met.
>
>Ken Pepke
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