flyboydale54
Posts: 20
Score: 104
Joined: 4/26/2009
Last Login: 5/23/2013
From: Gouverneur, NY, USA
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Running all engines on a test stand for me is the best thing I can do to make sure the engine gets broken in some before trying to fly it in any of my RC Airplanes. However, I have come up with a method that works flawlessly and will keep the engine from running too hot. First and foremost, I leave the engine rich on the high speed. While I am breaking it in, I do not care if it idles well, as that is not my purpose on the first few tanks of fuel. Secondly, I have learned from a pro that the best way to break in any engine is to run it for 1-2 minute durations at full throttle. Then shut it down and let it cool completely, followed by repeats of this for a couple tanks of fuel minimum. Then I increase the time and let it run for 3-4 minutes, shut it down, and let it cool between runs for another 2-3 tanks of fuel. For reasons I believe in very much, I then increase the time to 5 minute runs for an additional tank or two. Then and only then do I put the load on the engine by putting it into the model airplane. The reason for this is because the engine crankcases, cylinders, pistons, rings and bearings all get hot when the engines are new. The other reason is the metal expansion and cool down is what breaks it in best and I have seen a major difference when I use this cool down method of limiting the time run before shutting it off and allowing the engine to cool. By using this method I have experienced more powerful engines consistently, as well as not overheating them during the break-in which is very important. The cowl does not need to be on the airplane the first few flights. I prefer to run without the cowl for at least 3-5 tanks of fuel. I have seen several people insisting on breaking their engines in on the airplane in the air, or worse yet, on the ground with the cowl in place. I need not convey the huge cloud of smoke coming off the engine and what this does to the engine. Bottom line, it ruins it permently, in my opinion and in my experience. Once you overheat the crankcase, cylinder and piston ring to that point, the engine is junk and will always have tuning issues. I use another neat tool to make sure the engine is getting plenty of air blowing across the cylinder and head. Many people have told me how unsafe it is, but with a little forethought, there is no danger in using a box fan turned on high in front of the engine. Naturally you can not expect the fan not to be pulled into the prop if you just set it in front of the engine. But, if you anchor the box fan down in a rigid frame structure, this will never happen and you will not smoke the engine as long as you are running the engine rich. As the engine loosens up, I then lean the engine just a litte at a time on each run after that until I feel it is breaking in some. It is at this point that I lean the low speed and the high speed just enough to achieve a reliable idle and smooth throttle transition. My personal preference of using this break in method will achieve consistant breaking in of the engines. Hey, try it and see the difference it makes. I know one thing, you will not smoke the engine using this method and it will consistently achieve stronger running engines that will last far longer than the smoke-um, fly them method. Leaving the cowl off the first few flights in the air will definitely make for a cooler running engine to get it broken in enough that heat is no longer a big issue. Way too many people are leaning their engines far leaner than they should. You should not try and achieve maximum RPM by leaning it down too far. But it should not run rough either from being too rich. Don't forget to check the nuts and bolts often to make sure they are not loosening up and leaking air, which makes the engine run lean. Oil is an engines best friend, and over leaning the engine to the point you see gray colored fuel all over the plane near the exhaust means your wearing the metal out of your engine. It does not hurt to run a little extra oil in the fuel during break in. This will save your engine. Engines are expensive, so treat them with the above care and you will see a big difference in the reliability during your flights. You do not have to bother using my method, but if you do, you will not be sorry you did. Hey, in my early years of flying when I was a teenager and probably until my 20's, I smoked my share of engines too, but not anymore since I use the above method, I am very happy. I read a lot about how touchy the Super Tigre Engines are to tune, but I do not have that problem, no matter which size engine I have bought. Mine run great since I use my method of breaking them in now. They last for years of flying too. For example, I love my Bridi Super Kaos 60, which I have had for about 40 years, and I have only had 3 engines in it, a Super Tigre 61ABC, ST-75, nice little step up, and recently changed that to a ST-90 for unlimited vertical performance. The heads turn when I yank it straight up after the wheels leave the ground and climb out of sight, :-). As for gas engines that are 2-cycle, I believe running them rich and keeping the runs short along with the cool down procedure, they break in nice and remain strong throughout their lifetime. It does not matter if it is Weed Eater, Chainsaw, or any other air cooled engine, the procedure works very well. Hope this helps those not so experienced in engine breakin and tuning.
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All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> Gas Engines >> Spare Zenoah G-38 
Spare Zenoah G-38 - 
Any and all advice is appreciated
