582 rotary valve leak

[BrentB]

A friend with an older Rotax 582 is using rotary valve oil.
No sign of leaking, so supposing it's internal.

We are wondering it it is safe to fly as long as the reservoir is kept filled.

Is the lost oil going into the combustion chamber and being exhausted?
With the usual 1-2 hr flight, it has been no problem keeping oil in the reservior, with it going down abt 1/4 in 2 hrs of flight.

Of course the A&P will say overhaul now, but would like some time to check into options while flying.
Otherwise, engine performing very well.

Thanks for any advice.

[scottessex]

If you have excessive oil it will lean the mixture. The bad thing is that the inner crank seals are almost impossible to replace. The crank has to be dissassembled, rotax does NOT recommend this on the aircraft engines, as the cranks are pressed together.
So it looks like you will need a new crank.
Does it burn enough to start fouling the spark plugs? Is it causing carbon build up on the piston?

[gyro]

After time, they will start to use some oil. I started using castrol synthetic 20/50 this year. I completely purged the system with a vacuum pump and put in the new stuff. I had been using the same oil (quicksilver) for the injector. I was loosing about a 1/6" after a good week of flyn. Since I switched over back in March I have not lost a drop.

If it is not evident on the outside of the engine then more than likely it is being consumed during combustion. If you are only loosing a 1/4" in that little 2x1 reservoir then I would not worry about it. That is a very small amount (But you don’t want to forget that it is using it and let it go dry....add that to your check list.

[BrentB]

Scott:
Thanks for your help.
I did consider the probability of leaning, due to the additional oil.
Plugs are staying good, and when working on the engine this winter [not many hours since] there did not seem to be a cabon problem.
Have just discovered the rotary valve oil usage, and haven't pulled the exhaust yet.
Will do that today and get back to you [after also checking the plugs.]

Thank you.
You got me started.
We're talking about a new engine, but I didn't know if there is a safety concern meanwhile.

Thanks!

[BrentB]

Thanks Gyro!

[scottessex]

As long as it is not making the rings stick...or fouling spark plugs....Fly and enjoy, just do not fly over anything you can't land on! :)

[Lee Scatt]

If you have excessive oil it will lean the mixture.

Explain this to me. I can't grasp this.

[BrentB]

I'm using a 50:1 gas to oil mix.
Any additional oli beyond that would make for less gas in the mix.
That would tend to lean the mixture, however slightly, since the oil is less combustable.
It's probably not measurable with the increase from the rotary valve, but the guys running 80:1 are certainly running richer.

[Lee Scatt]

Brent, the oil entering the mixture due to rotary valve leak is not flowing thru the jets in a gas -oil mixture, it is entering post carburetor, so it will merely enrichen the oil ratio.

[scottessex]

Good point Lee.....It was early, I didn't get much sleep.. :)

You are correct, if the oil is not part of the fuel mixture, it will just richen the oil ratio in that cylinder.

[Jazzenjohn]

Will the oil go into the cylinder and be burned, or go into the crankcase and pool at the bottom?

[scottessex]

Anything in a 2 stroke crankcase, goes into the cylinder, to be burned, including but not limited to: oil, bugs, reed valves, pieces of foam air filter, nuts, bolts. On a 2 stroke the crank case is part of the intake system.

[D.Paymn]

Seals went on mine a rotary pump on a 3b. The top seal and a bunch of O rings were replaced without removing pump cost approx 100. That was about a year ago. I am in WGTN.

Pete