Results of testing:

I mixed up some fuel using my new modified olive oil today and did some static testing. I basically just modified Stewart's brew a bit: 20%ether, 11% 10w-40 diesel engine lube, 11% modified olive oil, 2% octyl nitrate (Amsoil) and 56% kerosene (actually a little less, since I counted the hexane in the JD starting fluid I used as part of the kero). The diesel engine lube was Shell Rotella and I noticed it mixed instantly with the kero.

I also mixed up Andy W's 40/40/20 to use as primer if needed, using modified olive oil for the 20% lube.

First, I tried my Norvel 1cc conversion. It loved the 40/40/20 as a prime but it took some playing around to get the 20% ether brew to catch. When it did, the engine ran strongly at nearly 10K rpm on a 7X3 inch prop. However, compression setting and needle setting were touchy. Throttling was poor. After about a minute or so of running the engine would sag and die. . .no fiddling with compression or needle had any effect. The engine was very hot and wouldn't restart. The engine has a pretty good "pinch" at TDC but this was gone and the resistance to being turned was much less. As soon as the engine cooled, the pinch returned and it could be restarted--but always with the same result. I pulled the head to check things out and found an adequate amount of oil and no evidence of seizing or distress. The piston and head were very clean and there was no evidence of oil burning.

I was disappointed by the Norvel but tried the same new mix in my .40 OS FP conversion. I didn't change any settings from my old mix or use any prime, aside from pulling fuel from the tank by choking the carb for one turn of the prop before applying the starter. To my surprise, the engine fired right off as usual. A touch-up on the needle valve and I was rewarded with noticeably higher rpm and much more thrust than I usually get from this engine. It throttled quite well and idled without a problem. While the engine ran warmer than usual, it wasn't as hot as if it had run on glow fuel. I didn't hear any clattering or signs of overcompression. In fact, the engine seemed to run quite smoothly. I pulled the head afterwards and found adequate oil and evidence that the new blend was actually cleaning up some of the old carbon deposit. I'm dying to try this one out in the air as I am hoping to get a performance increase.

My guess would be that my Norvel needs more oil to help dissipate the heat and retain a good compression seal while running. . .something that I now think that Reg's high oil brew does in his small engines. Unless my OS .40 (6.5cc) shows some sign of distress, I think I'll run a few tanks worth of this new blend through it. If all else fails, I now know the Norvel loves 40/40/20--but I'll try Reg's approach first.