I like the burn out feature, too. It really started working for me on Pee Wee .020s when I went to a thinner teflon seal than Davis supplied originally. It was easier to cut new seals than go to the hobby shop and pick up another crank or a piston/cylinder assembly. A Pee Wee turning a 6x2 or 6x3 wooden prop is a pretty stout engine.
Lou,
That feature was one of the things Davis touted as an advantage of his head. The idea is that running over-compressed (and thus overheated) would blow the seal instead of your engine. Some like that feature, some don't. I do.
George