Greg, I have used syn diesel fuel in one of my late 1940's side port design Oliver Jaguar 2.5 cc engines 2 years ago. I have three of these Jaguars and this is the dog of the bunch and I use as a test engine. I use this engine to test fuels and props. Using fuel that contained the syn diesel fuel the 2.5 cc engine turned an APC 12/7 prop at 5,100 rpm and got 6:09 time on 1/2 ounce of fuel. With kerosene I got 4,900 rpm with 7:51 time on 1/2 ounce of fuel. I had to use a bit more compression with the syn fuel but same needle valve setting. 49% syn diesel, 33% ether, 16% castor and 2% ignition improver. Same percentages with the kerosene based fuel. I warmed the engine up first with a couple of tanks of Olde Engish Mix fuel before trying the 2 special mixes. I then alternated between the mixtures make 3 runs each with syn and kerosene. The rpm and times are averages of the 3 runs for each type of fuel. JackI use this engine to test fuels and props. Using fuel that contained the syn diesel fuel the 2.5 cc engine turned an APC 12/7 prop at 5,100 rpm and got 6:09 time on 1/2 ounce of fuel. With kerosene I got 4,900 rpm with 7:51 time on 1/2 ounce of fuel. I had to use a bit more compression with the syn fuel but same needle valve setting. 49% syn diesel, 33% ether, 16% castor and 2% ignition improver. Same percentages with the kerosene based fuel. I warmed the engine up first with a couple of tanks of Olde Engish Mix fuel before trying the 2 special mixes. I then alternated between the mixtures make 3 runs each with syn and kerosene. The rpm and times are averages of the 3 runs for each type of fuel. Jack