FOX 35 ABC

I put an ABC kit in a Fox 35. Suggestions on Break in and fuel. Some suggested Superfuel was not required for this combination. This was disussed in a thread some time ago but I cannot find it.

Thanks, Bob

I believe you can use 28% oil, 1/2 castor and 1/2 synthetic in your engine and not hurt it. The synthetic will help prevent varnish. The reason you need the high oil content is the small main bearing which wears out pretty quickly if not properly lubricated.

Probably the 1/2 castor and 1/2 synthetic will work, but the important thing is not to run this engine rich on a test stand; it has to get up to temperature as fast as possible. In fact most engine experts suggest you heat an abc engine with a heat gun before starting it the first time, this takes the stress of the connecting rod as abc are setup very tight. I would break this in with a 9/6 prop running at a very fast 2 cycle, not lean but fast this way the liner and the piston can expand properly. If you run it rich like a ringed engine or a standard Fox it will cause what is called a cold seizure (in other words the piston expanded before the liner and will damage the chrome bore); I have seem many engines damaged like this. A friend of mine ruined a brand new Moki 15 that was going to be ussed in Clown racing and since there was no parts available he had to send the engine out to GMA, George (God bless his soul) rechromed it but never got to finish it but my friend did get the engine returned to him, all this because he ran it rich. Recently I saw 2 Fox 40 deluxe ruined the same way; only the wrist pin clips popped out when it seized and totaled everything, so man run it hard but not lean. I have 2 abc Foxes 35, one in a Super Clown and the other in my Bi-Slob and both run great.
Jim

One of my very few claims to "firsts" in this event is that I was the first to run an ABC-equipped Fox 35, as GMA and I got together on this project back when I was still doing business in Russia.

I tried to use fuel with various percentages of Klotz and castor, generally in 50/50 ratios. Such a fuel will work, no doubt. But it was not until finally giving in, using all-castor fuel and generally at 25%, that the motors finally gave that little bit of extra performance in a pure Stunt-type run.

Not incidentally, fuel mileage went up, although I would have to check my notes prior to making any claims.

I put one of these in a plane. It runs very nice. I didn't do anything special for break in, just put it in a plane and flew it. As I remember, it probably ran a solid two cycle for several flights before I got it properly richened up for a stunt run.

Mine won't run on 25% oil. I've had to go to the standard 28-29% oil mix. I add about 12 oz. of castor to regular 15% RC fuel to get roughly 12% nitro and 29% oil. It runs well on that. On 25% oil it immediately leans out to a 2 cycle, no matter what the setting on the ground.