2 stroke engine failure!!!

[Bluey]

Hi all;

 

Just wondering if anyone out there flying a rotax 2 stroke has ever had any warning before their engine has failed on them. I heard of one story a few years ago where a a pilot with passenger took off from YWOL and noticed that the engine seemed a little low on power. At the time the pilot who had over 5000 hrs under his belt in microlights put it down to the hot weather. Anyway, a short time later while again taking off from a short field about 10 miles from the airstrip, the engine lost the crank and slowly failed. This all happened at about 350 feet. The pilot somehow managed to do a near 360 and land back on the same field. Not sure how they made it even in a microlight from that altitude??? Anyway, another story, also with a happy ending, occurring again at YWOL just last year saw another microlight with passenger have a seizure at 400ft over the main runway. No warning what so ever and the engine was restarted easily after landing. The engine had 440 odd hours at the time and seemed to be running very well up until that point. The engine was replaced and no cause was ever determined.

 

Regards: Bluey.

 

 

[facthunter]

Failure, 2-stroke engines.

 

When a 2-stroke fails it is usually when on a fairly high power setting when the maximum amount of damage is experienced, and it is usually sudden ..Melted hole in one piston, rings/piston seizing, big end roller bearing seizure or breakage and crankshaft breakage, covers most of it. Running lean is disastrous for a 2-stroke engine, as is detonation. Never keep flying one which is in any way suspect as to smoothness and power delivery.. They have their place and provided they are looked after can give a good service life. I reckon that once you have say 600 hours out of it you have had a good run, and the crank is supposed to be lifed at 300 hours on a 582. I think the best approach is to scrap the engine rather than spend much money on it and INVEST in a new one, as it works out cheaper in the long run. It's your neck and you just have to allow so much per hour towards the engine replacement.. Nev..

 

 

[Guest hatrack]

I blew a hole in a 503 piston, twice. First time I was at 90% power in level flight and had 4 seconds warning. I started to lose airspeed and added the last of what I could get out of the engine but was fighting a losing battle. Vibration increased in the last 2 or 3 seconds then the engine seized. I had been cruising for 45 mins. The engine had 54 mm Mikunis instead of the standard 50 mm Bings. I had a single EGT on the rear pot but of course that was on the pot that survived. The front pot runs marginally hotter on my pusher I now know.

 

So I invested in a dual EGT, rebuilt the engine, and 140 hours later blew another hole in a piston in the same pot. This time I had no warning. I was on climb out at 50 feet and the engine continued to run on one cylinder, while I turned, landed downwind and even taxied back to the tarmac. I thought I had fouled a plug (single ignition). I had just completed a 2 hour cross country, refuelled and back up again within 20 mins to do some circuits. The EGT definitely never increased while this happened, I can definitely state. Richard Eacott had told me that this is often the case. It was quite warm at noon in a February. The Mikunis were obviously running too lean in hindsight.

 

I have since installed a new DIDC 503, and am burning 15% more fuel which supports my theory. But I am loathe to lean out the engine and prefer the reliability factor instead. I am burning up to 26 litres an hour flat stick. EGT of 1050 degrees.

 

Anyone out there reckon I could drop down a notch on the jets? Anyone burn as much flat stick?

 

I was dubious when I first bought the machine (my first) because I have never liked 2-strokes much, but I must say I am quite impressed now. Low maintenance and if tuned properly, love being flogged!

 

 

[Tomo]

Well there's no warning when my instructor cuts the power on take off...!!!

 

 

[jetboy]

No warning here,

 

503 just dropped a few hundred rpm during climbout and by the time I'd cycled the throttle setting the prop had stopped. Engine had been running very well prior to this incident which was caused by needle rollers exiting the cylinder and breaking rings on the way.

 

Facthunter has it right dont bother refurbishing its actually more economical to replace and pass it further down the food chain when its met its design life (300hrs)

 

Ralph

 

 

[Yenn]

A friend of mine had a Supercat with a 503. He and several of us flew to an island adjacent to the one he lived on and when it came time to leave his wouldn't start.

 

We took the cowls offand checked everything, including turning it over by hand. Replaced the cowls and it started so he took off sounding as usual and went home about 5 miles.

 

Next time I saw him he had the engine in the back of his ute. The cylinder head looked as if had been attacked with a hammer. The piston was similar, but the surprise was that it was a failed little end bearing which nhad caused all the trouble.

 

It was amazing that it ran smoothly right up to the time he stopped it and then failed to start again.

 

 

[Tomo]

It was amazing that it ran smoothly right up to the time he stopped it and then failed to start again.

You know, I had my old go-cart engine do that, it's an old Briggs and Stratton, it was running perfectly. I stopped it, and when I came back later to start it again, I had no compression at all, I thought, 'Gee that's weird!' but yeah, it just spun around and around with no obstruction what so ever...! So I quickly pulled the head off, and pushed on the piston and it went straight down!! In the end I pulled the whole thing apart, and yeah the Con-Rod had broken right on the small end bush!

 

So yeah, it was still running with it broken, but obviously the firing of the piston kept it together!;)

 

 

[icebob]

Hi,

 

I have had all the motors(3 - 1x 503 & 2 582's) that failed all at mid to high RPM.

 

Facehunter is correct at 600 hours get a new one, I sell my old motors to the go-cart mobs as is, you can get a fair price for them too.

 

Bob.

 

 

[farri]

[quote=facthunter;

 

I reckon that once you have say 600 hours out of it you have had a good run, and the crank is supposed to be lifed at 300 hours on a 582. I think the best approach is to scrap the engine rather than spend much money on it and INVEST in a new one.

 

Nev..

 

I will second that,

 

I`ve had 4, 582 engines,3 went over 600 hrs but didn`t make 700,all crankshaft bearing failures.

 

I replaced the crankshaft in the 4th at 500 hrs, did a further 550 then scrapped it.

 

The worst part is that they will run well right up to the point where they fall apart,with hardly any warning.

 

Frank.

 

 

[skeptic36]

Facehunter

Poor bloke, sounds like a character from Dr Who

[icebob]

Hi,

 

opps sorry, can blame sleep dep: for the poor spellinggss, sorry.

 

 

[Turbo_Boss]

Hello Guys,

 

Talking about failed two cycles engines

 

This almost new Rotax 582 Blue Head with only 100 hrs in a Quicksilver MXII decide to quit in the air. Emergency landing was ok with no damage to the Quicksilver neither to the pilot.

 

This engine is oil injection and use alway Penzoil oil

 

The engine was working perfect and sudenly the RPM beguin to drop until it stop completely :( Everything took like 5 seconds)

 

We decide to open the motor and we remove "only" the cylinders. This is what we found.

 

If you check the pics you will see a cooper color part. This part was stuck on the crankshaft.

 

Were this part coming from? Were it goes in the engine and why this happened?

 

Any clue?

 

Next week I will take apart the crank case to see what I found.

 

THX,

 

Isaac

 

 

 

 

 

 

 

[icebob]

Hi,

 

It sort of looks like the case/cage of a roller bearing???

 

Bob.

 

 

[stanzahero]

To me it looks like a part of a big end bearing or a small end bush.

 

I'm not familiar with the construction, but most plain bearings are white metal (a tin alloy) overlayed onto a harder copper alloy with a steel base.

 

the damage to the top of the piston would be due to metal transfer through the inlet port.

 

Try to hold the crank still and see if there is movement either in the conrod big end or the small end. If it has come from either of these two areas you will be able to move the piston in a twisting fashion.

 

The second piston looks as if it had been running well because there is very little scuffing apparent around the crown.

 

Stanzahero

 

 

[facthunter]

What bit?

 

Looks like one of the big end thrust washers to me. Check the end float of the con-rod in the affected cylinder. Won't be the small end as that is needle rollers. Nev..

 

 

[Yenn]

Looking at the parts list it is possibly the distance ring, or spacer on the cramkshaft between the 2 cylinders. Whatever it is it looks costly as the crankshafts require specialised gear to work on them.

 

 

[facthunter]

From here.

 

Regardless it needs a complete rebuild. It works out cheaper to buy a NEW motor. How many hours had it done total? Nev

 

 

[Turbo_Boss]

Regardless it needs a complete rebuild. It works out cheaper to buy a NEW motor. How many hours had it done total? Nev

This engine only has 100hrs...............

 

New Crankshaft is around $1,400

 

Boaring the 2 cylinders to fix the scrash that have one $$

 

New pistons/rings,etc $$

 

Gasket $$

 

Importing everything to our country $$

 

It will be better to get a new engine to be on the safe side. The owner already order a completey new 0 hrs Rotax 582

 

Isaac

 

 

[Yenn]

So did you find out what was the cause of trhe problem, just to make sure it doesn't happen again. It seems like a major fault for a 100 hour old engine.

 

 

[facthunter]

Repair/replace.

 

Check the crankcase for damage before you decide anything. Forgive me for not noticing the hours (you had already stated 100). That is very LOW hours for a failure to occur. You would want to know why that happened. I haven' seen that type of damage before. Nev..

 

 

[rotax618]

G'day, there is a good explaination of 2 stroke failure here two strokes

 

from my experience this article is spot-on

 

Cheers Tom C

 

 

[Guest AirBorne Flights]

Its not good to have any sought of engine failure in an aircraft.

 

You really need to find out why this happened, as i don't think you want this to happen again. if it is oil injected, do you know for sure that it was getting adequate amount of oil? I notice on some oil injected 2 stroke rotax 582 that they get little air bubbles in the oil feed line, not good for the engine. Maybe just check the 2 oil lines that go to the back of the carbs.

 

Cheers Criso ;)