Rotax 582 Blue head failure

If the oil injection cable breaks, it should be spring loaded to the max oiling position.
 
582 blue head failure

582 blue head failure

if an oil injected engine builds carb ice or runs rich for any reason it will wash out the oil and cause rod bearing failure, I had a customer last year destroy an engine due to the choke/ cold start valve didn't close properly and his engine did the same thing as yours. When a rod bearing starts to run hot it burns most of the oil in that side so it is normal for it to look kinda dry in there. when rotary valves start to wear to much they blow across to the other cylinder and it can lean out one side or the other.
Norm
 
On a 582 if the cable breaks the pump will go to oil lean. On a 503 if the cable breaks it will go to oil rich.
 
You would think that rotax would have designed the 582 to go to full rich ??
 
If I remember right if the oil pump is at full oil lean it is still 100:1. I know a guy that changed his oil injection filter and did not bleed the oil line afterwords . He cooked his engine. I wonder if there was any maint done to that engine lately?
 
Wait, what? One engine goes full rich, the other full lean? Somethin don't sound right. I remember ALL the Mikuni pumps spring loaded to full rich. Why the hell would they go to lean?:wacko:
 
I know . It dosent make sense. Thats what the mm says.
 
582 blue head failure

582 blue head failure

some pumps have a stop pin adt idle newer pumps have no pin and will go past idle and to the full rich position, the internal parts of both pumps are the same.
Norm
 
You had a cylinder run lean and caused the needle-bearing to fail due to lack of fuel and lubrication. You need the fuel to carry the oil droplets to the bearings.

Check the vent to your carburetor bowl, and check the needle inlet as well and make sure it was working to let in fuel.

Or,

Check to see if you had something clogging the main jet.

Or,

Make sure the needle clip didn't come off or brake and drop down.

In other words, look elsewhere for the problem, not the engine block.
 
Last edited:
582 Blue Head Failure follow up

582 Blue Head Failure follow up

OK, its my blue head that Ron posted about, and as I just got back from having it checked, I thought I'd let you know what was found. First, many thanks to Ultracruiser (aka Barry, or Beemerboy....) and Gyroron for their help. I might still be out in that field if it wasn't for them.

Turns out Phantom has it pretty much nailed. It was a big end rod bearing failure. Needle bearings looked okay. No indication of lubrication failure in either cylinder. The seizure happened quickly and the tech was surprised at how little damage was done (other than the hole in the crank case). Heads looked good and only need a little work, cylinders still look pretty good. The PTO piston that seized didn't look as bad as I, or the tech, thought it might. Tech was also surprised that no damage done to rotary valve, indicating that little to nothing was spit back into the carbs. I had gone back and checked the carbs, expecting to find that the PTO carb was hung up in some way, causing the throttle cable to be off. Carbs look okay, and slides work as they should. The tech didn't feel that he could tell why the bearing seized. In internet searches, I have found quite a few similar incidents of rod bearings seizing.

thanks for all the input.

Bernard
 
Sounds to me like the jury is still out...
I could see the bearing cage failure idea.
Would definitley be catastrophic.
Seems to me there is no real forces at play on the cage assy.
Tons of motors use them just fine.
I'm more inclined to suspect an issue on the related piston.
Hot, dry, lean, fodd, you pick one.
My 2 sickle days have seen VERY few bottom end issues.
Top end is always first to complain when unhappy.
Better be damn sure of the carbs before slammin them on a fresh block.
Then again, what do I know...
 
Sorry but the jury is not still out. Engine was dismantled and rod bearing was toast. Needle bearings were fine. Just do a search for rod bearing failures and you'll find many. Carbs look fine but the Rotax tech will be checking them further to make sure no garbage got thrown back.
 
UHHH, "rod bearing was toast, needle bearings were fine". If memory serves, the only needle bearings in a 582 are on the ROD, big end, and little end. The crank rides on big ol BALL bearings bro. What say yee jury?
 
Used to turn my ol 225 Yamaha outboard 8500 rpm all weekend long for many a summer on my 17ft. Hydrastream. The rod big end was of the 'cracked', bolted rod cap design.
Each rod/cap were unique, and only fit each other. A pencil was to be rubbed across the torqued rod cap intersection to verify a perfectly flush fit. It used needle cages, but they were quite robust though. I read somewhere that a gram of static piston weight equaled a pound at 7000 rpm's. Hmm...
 
Thanks Dennis,

Had an issue that was very specific and showed a difference in EGT's from one cylinder to another. I didn't check the carb vent on that cyl. That was it. Again, thanks.

Phil.

A rod bearing failure is usually a symptom and not a cause. I'd look a little closer, before eating another motor.
 
UHHH, "rod bearing was toast, needle bearings were fine". If memory serves, the only needle bearings in a 582 are on the ROD, big end, and little end. The crank rides on big ol BALL bearings bro. What say yee jury?

The rod bearing was toast, yes. The rod bearings on the crank end (yes, ball bearings) were toast. The cageless needle bearings at the piston end of the rod were fine. I reported that the engine had been disassembled and the bottom of the rod was where the issue was, and I guess I'm a little confused why you would say the jury is still out and that you think the problem originated at the top end of the rod.

Also, yes, the bearing failure could occur as a result of lack of lubrication or water getting in and rusting the ball bearings, or crud. Hense I said that the engine had no indications of a lack of lubrication or water (other than the seized ball bearings), or crud. The ball bearings were black. Ron did indicate in the original post that the PTO cylinder seemed very dry. The condition of the piston and the cylinder indicated no problem with lubrication (other than the seized bearing). Some dryness in the seized cylinder would be expected due to heat from the seizure and from the hole in the crank case, which would eliminate back pressure, and would allow oil to be blown out or leaked out after the stoppage. This is per the Rotax certified tech (who performed the tear down) as well as from the Lockwood tech I spoke to about it. Carbs have been looked at and will be inspected further by the tech. Not sure where else to check that hasn't been checked. Believe me, if something preventable caused the seizure, I'd like to know more than anyone.

I do appreciate any and all help.

Bernard
 
Top