Keith Evenson wrote: > Yesterday I went to the local airport and put > in 6 gal of 100 octane with the rest of the tank filled with 92. I am > still getting the noise but it is not as bad. So should I go to a > 50/50 mix or try lowering the timing more or is there something else > anyone can suggest? I have run it with the vacuum advance > disconnected and still getting it. Hmm, though it will kill performance, and extreme enough will overheat it, but if you back off timing sufficiently the pinging will stop -- that will tell you if it's a real detonation ping you are chasing, or some other noise. Lose 50, 75 hp for an hour while you diagnose. If you don't have a minimum amount of advance a lot of hot gases will go out the exhaust and really heat the head. With the vacuum disconnected, say 5 - 10 degrees static advance and 15 - 20 mechanical, it ought not ping if the compression ratio isn't astronomical. _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list