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Engine

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Posted

Got my engine delivered to Heavenbound Aviation today and got to look around in the engine shop for a while. An interesting observation was the number of 582's in his shop for rebuild. Must have been a half dozen or more in various stages of repair. I did notice several 582 cranks that were either worn out or destroyed bearings. I didn't ask about the # of hours on them. I only noticed 1 Hirth in the shop for gearbox repair. Either that means there are 10 times more Rotaxes out there than Hirth, or Hirth is more reliable. I tend to think there are that many more 582's out there which in turn means more overhauls. Most were for lower end problems on the crank. We talked about that and both seem to agree that oil injection could be a factor. I'll explain my theory on that. The oil injection nozzles is located close to the crankcase inlet so the oil and gas does not have time to mix well before entering the crankcase and does not get into the outer ends of the crank. Oil being heavier than gas so it gets to the crank near the intakes and the gas gets to the end bearings, where as pre-mix gets circulated throughout and deposited on the whole crank. This may be all hogwash, but it sure sounds reasonable. That's my story and I am sticking to it.

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Posted

Rotax have put a lot of thought into their oil injection system (ever noticed the little casting bump in the intake!)it works real well.  We had an issue with one of the club planes with premature wear,the oil injection was immediately blamed. The crank was replaced and This time the oil setup was checked,yup 100:1 AVEREGE oil mix!!!! . PLEASE all 582 owners check the oil is being delivered in the correct quantity (70:1 is good) these engines are incredibly reliable if set up and treated well.

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Posted

Oil injection has been used on outboards for years and most 582's use oil injection. But it has to be set up properly. No proof exist (yet) that oil injection causes any kind of bearing wear or failure. Just my opinion and I haven't used it. Would be hard to prove that it causes any problems anyhow.

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Posted

does Andy still run the show over there?

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Posted

does Andy still run the show over there?

Yes, but not as much as before. Too many irons in the fire. He went to Sebring Monday for the LSA show. He has a couple of good people working for him now. He now owns Stewart Systems, plus has a repair shop #2 in the Midwest.  But still has time to answer any questions one would have.

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Posted (edited)

I just finished switching to the OI system.  I put a stop on the oil throttle arm where the marks line up, so that should preclude going below 70:1.  The standard advice is to go 100:1 premix while you validate correct operation, but at the risk of spark-plug fouling (oh horrors!), I am going to run 50:1 until I have indications that things are set up correctly.  Don't want to have an engine failure.  It's so easy to remove &  clean the plugs!  Motorcycle racers say the compression gets better when running oil-rich, the limit being carb setup, i.e. jetting. No interest in messing with that.

My chief worry regarding going premix is getting adequate oil mixing in the tank on fill-up at airports.  The wing tank is a weird shape with remote corners.  Can't shake it, and don't want to wait for molecular diffusion to accomplish the mixing!  Maybe I'm just being a worry-wart, and over-thinking this.  Dunno.

Edited by Turbo

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Posted

Mixing in a wing tank isn't the best way. If fueling at other airports often, oil injection is the better option. For some it may be the only viable option.

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Posted (edited)

I just finished switching to the OI system.  I put a stop on the oil throttle arm where the marks line up, so that should preclude going below 70:1.  The standard advice is to go 100:1 premix while you validate correct operation, but at the risk of spark-plug fouling (oh horrors!), I am going to run 50:1 until I have indications that things are set up correctly.  Don't want to have an engine failure.  It's so easy to remove &  clean the plugs!  Motorcycle racers say the compression gets better when running oil-rich, the limit being carb setup, i.e. jetting. No interest in messing with that.

My chief worry regarding going premix is getting adequate oil mixing in the tank on fill-up at airports.  The wing tank is a weird shape with remote corners.  Can't shake it, and don't want to wait for molecular diffusion to accomplish the mixing!  Maybe I'm just being a worry-wart, and over-thinking this.  Dunno.

I will bet the typical black gunk plug fouling is not oil, it is rich gas mixture from the pre-historic Bing non-mixture system. With my Hacman to lean to 1050-1100 degrees on my 582, and automatic 50:1 mixing, I had pretty unfouled light brown plugs for many many hours. That included a long flight across the Rockies at 10,000 feet, prime territory for fouled plugs.

Also, I would always follow the manufacturer's 50:1 recommendation. That is the only primary lube!

BTW thanks for the great aero advice you always post, very cool.

Edited by nlappos

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Posted

Has throttle body injection (like the Rotec system) ever been tried?

 

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