Asking technical experts the same question about exhaust valve recession problems with unleaded fuel and you’ll get a variety of answers — and each person is convinced they are right.
Swift Fuels
Swift Fuels UL94 now purple
The color change, the result of more than four years of planning by ASTM International, is designed to increase avgas refueling safety in the marketplace by helping differentiate various fuel grades, as well as water, from one another, according to Swift Fuels officials.