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Engine basics => Engine set up tips => Topic started by: Dennis Toth on May 26, 2019, 06:58:23 PM
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Guys,
I have an ABC Fox 35, the p/c was from GMA. The engine as only a few runs, was very tight when I last I tried it and was difficult to needle. I pulled the P/C and did some light lapping which loosened it a bit but it still has a good pinch. Question is how much break-in is needed for this set-up? I'm assuming that 10%N, 25% (50/50) oil will work. Anyone running one of these?
Best, DennisT
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Guys,
I have an ABC Fox 35, the p/c was from GMA. The engine as only a few runs, was very tight when I last I tried it and was difficult to needle. I pulled the P/C and did some light lapping which loosened it a bit but it still has a good pinch. Question is how much break-in is needed for this set-up? I'm assuming that 10%N, 25% (50/50) oil will work. Anyone running one of these?
Best, DennisT
You need to forget it's a Fox and heat cycle it like any other ABC engine, which is a lot of short 2 minute runs. The ABC sets that Brian Gardner produces fit very well and on the tight side, and he calls for a half dozen 1 minute runs with cooling in between, then easy flights on a model, with RPM just shy of a two stroke. The main thing is to get it to operating temp quickly and don't baby it too much. Watch the prop load for the first dozen flights or so.
Type at you later,
Dan McEntee
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I am breaking in one as well, using all castor. Is that a good idea, or should I switch to a 50/50 blend? So far, I have run it for four times, two minutes each time with a long cool down between runs.
Regards,
Brew
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I am breaking in one as well, using all castor. Is that a good idea, or should I switch to a 50/50 blend? So far, I have run it for four times, two minutes each time with a long cool down between runs.
Are you running an ABC system? If so, you have greatly reduce the castor, and heat is your friend. Cold starts and rich running are enemies here, you will greatly stress the crank and crankpin. Knowing how GMA set things up, It's liable to be far too tapered/tight at TDC for reliable stunt running unless it is extremely hot.
Brett
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Brett -
The ABC piston/liner that I am using is the one that was sold for some time by Fox Mfg. I am going to switch over to the 50/50 castor & syn fuel and complete the breakin.
Regards,
Brew
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Brett -
The ABC piston/liner that I am using is the one that was sold for some time by Fox Mfg. I am going to switch over to the 50/50 castor & syn fuel and complete the breakin.
I don't think you want all that castor oil, all it will do it varnish it up sooner, and I don't think it will keep your other bearing surfaces alive longer. I haven't seen the Fox version, so I don't know how much taper it has or how risky it is to run it cool. My suggestion would be Powermaster 10% "Air" with a maybe 5-8% extra Klotz (thin or regular) Techniplate, or similar SIG with modifications if you can't get Powermaster.
Brett
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Hi Harold
The FOX ABC sets that they ( i actually heard K&B made them) made are not fitted as tight as the aftermarket early ones that George had, use a minimum of 50% synth fuel with at least 25% total oil. run it 2 to 3 minutes at a time with cool down in between, Set the needle so it runs the cackle between a 4/2, NOT richer, then you can pinch the tube for a second to let it burst into a 2 cycle, after a couple runs, you can turn the needle IN to where the fOX will run in a 2 stroke , do this for 10 seconds the back to just between 4/2 stroke
8 to 10 runs should get it in shape to start flying. as stated do not run it very rich, nor very lean you want to bring it all up to temperature for breakin. I would highly recommend wood props to fly, and I would use a 10x4 wood for break-in
Randy