Rotax 582 Blue head failure

GyroRon

Former Gyro know it all
Joined
Oct 29, 2003
Messages
16,888
Location
Fort Mill South Carolina
Aircraft
Vans RV4 / Dominator 582 Ultrawhite
Total Flight Time
ALOT
Yesterday, ultracruiser and another pilot at our field and myself were up flying.... the other pilot was flying his X air ultralight plane with a 582. everything was going good when he noticed a slight drop of rpm and then seconds later the engine just locked up. Luckily he had a nice field right under him and he made a perfect landing. Barry and he retrieved the plane last night back to our airport and today I had a look at it.

The prop would only turn a few degrees in either direction. giving a once over and noticed on the underside of the engine, under the crankthrow for the front PTO cylinder, a nice hole in the bottom of the case. Took alot of force but finally got it to turn through enough to get the piston down below the exhaust port.

Upon inspection, the piston is missing the top ring. The top of the piston looks like it was blasted with a .410 shotgun, and then the bearings in the crank end of the connecting rod look trashed ( which is what I believe is jamming the engine up and keeping it from turning freely. Didn't take anything apart other than pulling the carbs and the exhaust. Rotary valve still rotates and appears to be in time..... I have no idea what broke. This engine only has a little over 200 hours and was running OIL INJECTION....... :der:

Inside of the engine looked like it wasn't all that oily, very little on the piston and the cylinders.... alot less than I usually see.

Anyway, now he is debating on what to do.... rebuild the current engine, buy a new engine, or possibly buy a used or " rebuilt " engine second hand. He is leaning heavy towards just a new engine minus carbs and gearbox and exhaust.

I am surprised, Rotax engines are pretty solid. Not sure why it failed. But something went wrong to blast a hole in the bottom of the crankcase and how in the heck does a ring go missing off the piston?????????
 
582 blue head failure

582 blue head failure

that sounds like a rod bearing failure , when the cage comes apart every roller shifts to the lower side and due to the extra distance the rod punches out the case, not likely worth rebuilding, would cost more than a new one unless you can find used parts.

Norm
 
You think the pistons top ring went first? The piston looks like crap, with what can be seen through the exhaust port.
 
My guess is lack of oil, or lean. Top ring siezed, failed and was ingested, punching the hole, accompanied by needle bearings. The rod bearings fail from the siezing piston load and no lube. I have found needle bearing pieces imbedded in piston crowns. Bummer.
 
I would have to agree with Michael....when Ron pulled off the carbs...the plate wasn't covered with oil like mine always look. (but then again...I dont run oil injection)

But....Bernard (the pilot) also said his throttle cable acted like it broke or stuck. When Ron looked at it....there was something definately not right with the travel...acted like it was getting jammed and it may possibly be the oil injection cable.

I think a ring stuck and broke and any garbage that dropped down into the case just didn't have enough clearance and the case broke out.

Just my 2 cents worth....but with todays' economy.....it's more like $ .0025.

Barry (well oiled) K
 
What kind of fuel? Avgas, or autogas, ethanol? Alitle bit of detonation will take care of the top ring in a hurry, what does the top of the piston look like?

That sucks, glad he landed OK.
 
Possibly the ring snagged the intake port, was destroyed and parts of it banged around up top, the rest deposited in the bottom end, jamming the bearings and punching the con-rod big end thru the case.
IF, it was a lubrication issue or seizure, there will be indicators on the good side. Bluing of the journal or cylinder wall scoring.
Check for the ring locating pin on the piston.
 
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I have never run nor liked oil injection on these machines. Just mix it and forget it if u ask me. Yeah a little more buildup but that is easily fixable, holes in the crankcase is a little different. Good Luck!
 
"The top of the piston looks like it was blasted with a .410 shotgun"

Kinda sounds like detonation from this description. Pictures would be a help.
 
Me too Scott.
it does sould like the top ring gave way, for what ever reason, denotionation, oil, or what ever. It was consumed by combustion and debri finished the motor off.
Before anyone jumps on us dumb oil injection types, a good examination of the other cylyinder will help. Restricted fuel flow will give the same results.
 
I don't know how needle bearing get on top of the piston with such close fitting parts. but they do land on top and will make bb indentions on the head and on the top of the piston.
 
582 blue head failure

582 blue head failure

what I usually see with rod bearing failure is what you describe, not only will the rod punch out the case but the piston wacks the cylinderhead and destroys the top ring, peices of bearing get sucked up through the transfer ports to do even more damage, on single carb I have seen peices of bearing thrown out the intake and end up in the side that didn,t fail. Rotax rotary valve systems can wear out of limits in in less than 100 hours so that could be part of the cause for this failure.
Norm
 
The spark plugs in the cylinder that failed looked somewhat rich, the plugs on the good cylinder looked normal to possibly even slightly lean.

The back cylinder looked damage free. Looks exactly as you would expect a good condition Rotax piston and cylinder to look. The front cylinder looks fine too, other than some vertical scratches in the walls. The side of that cylinders piston looked rough, like someone took high grit sandpaper to it. The top of that piston looked like there was pieces of the ring and possibly the bearings embedded in it. That is what I mean about blasted by a shotgun.... that all kinds of debris is lodged into it.

The bearings on the big end of the connecting rod are half missing and what is left it all bunched up on one side, hence the reason the rod punched a hole in the case.

The engine had oil in it, just very minimal amounts... I have never seen the insides of a two stroke engine as dry as that one with or without oil injection.

Yes the throttle cable was jamming up after the off field landing. The cable coming out of the 3 way splitter, that operated the oil pump is defective.... not sure why, but it was hard to retract or extend the cable. At time of engine failure though the cable would have been in a cruise position with the oil pump arm in the cruise throttle position as well.

Won't know more till the engine is pulled off the plane and is tore apart. If the owner decides to let me have some time with it, I will pull it apart just for the hell of it to see what I find.
 
.....sound like the oil injection cable broken in flight
pwongkit
 
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