Quote Originally Posted by efwd View Post
That is interesting. Doesn't a Lycoming need the lead? Thought that's why everybody has 100LL on the airport fuel pump.

No, the Lycoming doesn't need the lead. The lead is necessary to give the fuel certain needed characteristics - it's principally an octane booster. With older internal combustion engines the lead was helpful also to lubricate valve stems, but not with more modern engines having sodium-filled valves for instance (to transfer heat more readily and keep the valve stems cooler), etc. Metallurgy, design, and especially lubricants have all improved over the years.