Another thought on the DDD Teflon disk...

When Bob Davis introduced these, they were intended for reed Cox .049s. The changed pressures and loads in diesel conversions too easily overstressed the parts designed for glow use. We didn't have the bulletproof shafts that came available later.

The Teflon disk was like a fuse in an electric circuit. It would burn through before the engine hurt itself. They were and are inexpensive, so the slight inconvenience of swapping-in a new one was worth it.

Small props let the engines rev too high on diesel. A 7-4 or 7-3 prop restrained RPM and kept the compression/power loads down. The newer O-ring sealed conversion heads stand the higher loads pretty well, but I think I heard that that, too, can be overdone.

Bob, if you're listening, did I get that about right?