<<You cannot find a single reference in the SAE literature that attributes
any premature valve failure to the presence of oxygen in the exhaust stream >>

That's because there IS no oxygen in the exhaust stream.

It is a misconception that you mix fuel with air, burn it, and get exhaust
products which are water + carbon dioxide + excess unreacted ingredients.  If
you're running lean of peak, you don't have any oxygen molecules in the exhaust.
 If you're running rich of peak, you don't have any unburned gasoline in the
exhaust.

What you *really* have is an exhaust product mixture containing largely
carbon dioxide and water vapor, but also partially reacted ingredients and
partially decomposed (the precise term is "dissociated") products.  Where you sit on
this spectrum depends on many things, but the fuel-air ratio is probably the
biggest factor.  

Think of carbon monoxide and carbon dioxide in the exhaust -- if you had more
oxygen to start with you'd have more dioxide and less monoxide in the
exhaust, but you'd always have some of both.

Well, enough non-Lancair-related rambling.  What I *really* want to know is
why I can't run my IO-360 powered Lancair with autogas, but I can run my O-200
powered Cessna and the buddy's O-360 powered Skyhawk with autogas....

- Rob Wolf