I’ve been able to get some flying time in this summer. I put a few hours on an Enya 46-4C II with spark ignition. It has a CH Ignitions system installed. I bought it online at auction. It’s old, there was a note written in the box, “Run 6-28-88.” It uses the mechanical timing advance arrangement. I had some trouble tuning the engine initially, but it must have not been broken-in fully. After a couple hours of running it smoothed out, runs, and tunes well. I’ve been running varying percentages of castor oil (Maxima Castor 927 or Klotz Benol) or Klotz Original Techniplate with either straight methanol or E85. The E85 runs well, just a few hundred RPM down from methanol. I’m tempted to raise the compression ratio to increase performance.

Another project is an OS FS-52 spark conversion. It will have an RCEXL spark ignition. I see these systems are rated to 8000 RPM, so I’ll see what happens above that. They require a 1/4″-32 spark plug boot with resistor to be installed as they are supplied with boots for 10mm or 14mm plugs. These ignitions are mainly used with large 20+cc gasoline engines. The engine is also receiving a positive crankcase ventilation system like OS uses in the new FSa series. I hope this will keep the oil mess down and allow me to reduce the oil content in the fuel. I made a gasket for he rocker cover and sealed the backplate with anaerobic sealant. I also intend to try this engine with E85, and after some runtime will increase compression ratio to see if any power can be gained.

Diesel four stroke projects continue. I’ll be adding the crankcase ventilation system to my FS-48 along with a few other parts to freshen it up. Again, I hope to be able to reduce oil content in the fuel from the 10% I’m currently using. I hope to test fly the FS-91 in the coming weeks. The engine has been waiting since fall of 2007. I am also contemplating the OS FS-120 diesel conversion. If the .91 runs well on the airplane, I’ll try converting the 1.20.

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