Well, I don't know if it's really helping a101960, but I'm learning a lot, having read the whole Wikipedia topic "Octane Rating" (
http://en.wikipedia.org/wiki/Octane_rating#cite_note-6 ). I see where the 99 RON corresponds to the typical U.S. premium gas that I use with 9:1 pistons. As to the name of the method used for determining U.S. "octane", I found this:
"...in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2."However, we just say "octane."
John (a101960),
I see that BP is trial marketing BP Ultimate 102 at a very limited number of outlets but I don't know if any of these are close to you. Nevertheless, I would not think that you should actually need to go that high in RON rating to cure the pings. It's the other possible causes that need to be eliminated.
While I think timing, mixture or coke are still the most likely culprits, I amuse myself by trying to think of obscure causes for problems. I wonder if anyone here has seen examples of head gaskets not quite made correctly, wherein a small bit overhangs the cylinder. (I can't say I've seen it.) Such an intrusion could cause detonation or pre-ignition.
Finally, for now, I think you were being too modest or, maybe, tongue-in-cheek, when you said you were not mechanically inclined. I went back and looked over several of your historic posts and I would have to say they show a lot of knowledge, interest and mechanical understanding. Maybe it's this sticky problem making you less "inclined" to dig into the engine, yet again. Hang in there.
Richard L.