Rotax Engine Failure

[@lsebob]

I would not blame the bearings.I am confident that the melted a piston due is showing pre ignition damage. Since one but not both cylinders were damaged, I would try to determine the cause of lean or other pre-ignition issues for that cylinder. I agree with carlos that the preignition likely killed the bearings and not the other way around.

[@BaronVonEvil1]

Hmm, what type of oil was your friend running? The engine internals look dry as if it was not getting enough oil. The other possible problem is the engine may have been running too hot or lean. It looks like the damage piston had swelled in the cylinder bore causing the smearing of the aluminum on the piston. Pre-ignition could hammer the wrist pin needles leading to failure. Just a guess...

[@Olle1975]

Carlos G Thank you! He flew with good full synthetic oil but he flew with high rpm up and down for testing. I know that high rpm during descent let rise the egt in critical range, may be a part of that reason.

[@billcallahan9303]

Carlos G .....Senor Carlos, I've flown 2 stroke for 47 years. As long as you stay on top of a 2 stroke, they are reliable motors. I have towed hang gliders as high as 7,500 feet at 6,800 rpm, wide open, for years with no problemos! But maintenance is key! You have to know what you are doing. Adios compadre!

[@mindlessconsumer]

@@Olle1975 According to the engine experts on the KZbin video, "Rotax 912: Outside the Box?" (I know this was a 582), Rotax engines are designed for automotive gasoline, 91+ octane. The lead in 100LL (Avgas) causes yellow deposits on the piston tops and sludge in the oil tank and gearbox. I am not an expert, but others here have also pointed out there is carbon build-up in addition to all the damage. Avgas is available at airports but car gas is usually not, therefore many Rotax pilots use Avgas anyway. However, if you do use Avgas, it is prohibited to use fully synthetic oil, it must be petroleum or a blend. Also, Rotax requires those who use Avgas more than 30% of the time to perform many specific maintenance tasks more frequently. Also, Rotax had Shell develop customized oils which are ideal for Rotax engines called, "Aeroshell Sport Plus 2" for 2-strokes, "Aeroshell Sport Plus 4" for 4-strokes.

[@bearbait2221]

some 1 dropped in case when assembled lays in the bottom till it is sucked in to piston. I have seen this on wrist pins c clips dropped and thought lost but they fall in the case and high rpms find it for you and kills engine

[@jazzyjim76]

I had an incident where my 582 bluetop stopped over Stoney cross and i had to do an emergency landing. After taking the engine apart found the thrust bearings had given up causing the rods and piston not to run true this then caused the big end to break in two! Always warmed up, good oil etc etc and all on a low hours engine (150hrs). Even Rotax say the crank run out should be checked after 300hrs. Rotax even do a whole crank 'kit', bad design in my opinion with tiny thrust bearings.

[@fdryer5116]

Random KZbin viewing brought me here. It's interesting that America's Predator drone used a Rotax 914, four-cylinder, four-stroke, 101-horsepower engine, the same engine type commonly used on snowmobiles, turns the main drive shaft. With military adaptations of specific Rotax engines, there may be a large gap between certain Rotax engines deemed good enough for expensive drone use. A sport airplane with an unproven, non certified engine for aircraft use is open to many issues. I melted a two stroke dirt/street motorcycle when I inadvertently leaned out the oil mixture. This two stroke mechanically mixed oil and the melted needle bearings in the connecting rod showed the same wear from lack of oil lubrication.

[@aviatorjoe4153]

Rotax 912s and later were designed from the onset to be aviation engines. The two stroke family are all based on Rotax's recreational engine line. You only need to look at the Time Between Overhaul figures: the 582, arguably the best they have is rated at 300 hours. The 912? 2000.

[@pres68y]

Incorrect mixture/ bad fuel causing detonation.

[@reedsilvesan2197]

definition is also hard in the crankshaft if you haven't rebuilt that engine yet you need to have that crank thoroughly checked out by a competent Machinist

[@Erik-rp1hi]

Lean condition which causes overheating which causes piston seizure. The bearing breaking are an after thought.

[@reedsilvesan2197]

Erik 567 on that rotax 582 I agree it was a lean condition but what that causes is detonation and detonation beats the hell out of an engine including the rod the bearings the crank the Pistons and the head detonation is severely destructive in an engine most people don't realize how bad it is

[@robertwhite2322]

There appears to be multiple hotspots on everything. I don't see a good piston either. Those top ends are overheating. Not sure what Rotax has to say about cylinder baffling but that is not enough airflow through the engine. A CHT guage will tell you that. The oil was too hot and too thin. R&R all the bearings.

[@UncleKennysPlace]

I'd say that everything wrong with the engine started with the needle bearing loose in the engine. I don't see how the wrist pin needle bearings can escape during operation (having rebuilt hundreds of two-stroke engines, with one to four cylinders, piston ported, reed valve, and rotary valve!) Even if broken, there generally isn't much room up under the piston, and there doesn't appear to be an oil hole in the rod. Of course, dropping one in the crankcase during assembly will start a losing game of Russian Roulette. That's my guess.

[@FourthWayRanch]

they run these engines too lean and without enough oil in the gas, that's the cause of the "mysterious" engine failures for sure. run them rich and give up a little power

[@steveb7310]

Seems to me that thorough warmup is critical for these engines.

[@theoldbigmoose]

Detonation pure and simple. Fuel octane too low or running lean. The shock of detonation shattered the needle bearings.

[@dbmail545]

Never seen such damage but the top of the damaged piston looks like damage from detonation.

[@billwelter4101]

Piston seized, what oil are you running and correct ratio?

[@leneanderthalien]

not a oil problem,: if oil both cyclinder are destroyerd an dit's not the case, so incorrect mixture in the defect cylinder who cause detonation...

[@panther105]

Failures like this are fascinating, but also sickening. If we can learn from them then great but if it's just poor quality control at the factory then you never know when this kind of problem might bite someone else in the future...

[@thirdyiii9649]

What is the type of the shape of your cylinders?is it square or...

[@timtynan2787]

How many hours? Also are you running it on diesel. Both piston are horrible

[@conantdog]

I think you're lucky to have gotten home.

[@reedsilvesan2197]

from everything you're showing here this engine was running with severe detonation which was probably caused by a lean mixture definition not only beat the hell out of the Piston as you can see it also beats the hell out of bearings and I would probably change the rod because it beats the hell out of the rod too

[@BenjaminEsposti]

By the looks of it, I'd say that "normal" looking piston was heading towards failure as well. Looks like it was chipping? I wonder if the metal wasn't being cooled enough (or was just too hot at the surface.).

[@dennisswenson4266]

I keep telling people, buying a Rotax, is no substitute for a real aircraft engine!

[@banzaiib]

i'd rather have a honda auto conversion than a rotax, tbh.

[@tenlittleindians]

Was this engine rebuilt recently and how many hours were on it since it was last tore down? What cylinder temperatures were seen before failure? What exhaust temperatures before failure? Were the pins in the connecting rod during disassembly or just some of them? Was the keeper still intact prior to disassembly of the rear piston from the connecting rod?

[@jamiemezs9891]

Question how many hours was on the engine.

[@lightrose100]

Manufacturing defects, , if lack of oil the problem would be seen on both cylinder, I think a needle bearing was accidentally dropped in assembly

[@lesbest2]

The "Good piston" has the upper land melted thru.....NOT good. Both piston tops look horrible for a "couple of hours" of flying time, covered with carbon deposits from shitty fuel. That engine has been abused with crappy fuel.

[@EllDub]

Yeah, my thoughts exactly, it's been detonating like mad on both cylinders but the rear has suffered the worst of it. Poor thing, possible lean issue too

[@banzaiib]

@@EllDub I'm a terrestrial engine guy, and those pistons and cylinders all look horrendous... even compared to a Honda with 100k miles on it (which would be roughly equivalent to 1000 hours on an airplane, 'ish)...

[@alasdair4161]

There are several different signs pointing at lubrication failure. That engine also shows high service time. My guess is either the oil separated in the tank, over time, or it was running too lean. Another reason to always use high spec full synthetic 2 stroke oil is the lubrication stability for extended time in the mixed state. Modern fuel additives can attack mineral oil film strength over time. The lean state results in pre ignition which hammers the small end bearings. Forensic examination for surface discolouration or patterning will point to which fault caused them to fail, along with the cage.

[@kevinyoung8651]

I think I would bring along a good pair of walking shoes, drinking water, and not fly naked.

[@andymoore6719]

This happened to a friend after an overhaul. Replaced fuel jet - the new one was mislabeled and leaned engine. He now is a 4 stroke driver

[@sgtjonmcc]

They make Jet guage's I would suggest getting a set.

[@garypeatling7927]

Piston seized lack of lubrication small end failure after piston fail does it have autolub or mix in tank ? Take off auto lub mix in tank I personally would never trust 2stroke motor to give high performance and last unless it was made in Japan 30 years ago have seen outboard do it should have heat sensor on both barrels fitted to boat alarm goes off above certain temperature

[@billcallahan9303]

I wish Rotax would put those damn loose pins back in a damn CAGE! I've since gone back to CAGED bearings with NO problems which makes for a hell of a lot easier dissasembly & assembly!

[@Errol.C-nz]

I'd have to say...not a full set of needles on that wrist pin...& yeah, go for caged bearings...have to agree with signs on detonation...shouldn't have that level of deposits or...its done a lot more hrs, by the look of the "good" barrel wear

[@sgtjonmcc]

pro-tip use grease or a thick assembly lube to old the needles in place during reassembly

[@MrLunithy]

2nd cyld was too hot results in piston oversize and detonation pin bearings failed forcing oversize piston to move.

[@phlodel]

Friends don't let friends fly 2 strokes.

[@billcallahan9303]

Right. I've been flying 2 stroke 503s, 582s, and 618s for 48 years. One failure. The secret is to know your motor inside and out. I used to haul hang gliders with a 503. Full power 6800 rpm to 2,500 feet. No problems.

[@shortribslongbow5312]

Looks like a lot of questions need to be answered?

[@sirclarencedarrow]

I had a 582 (an old grey head) failure recently at about 500' AGL and one my pistons looked really terrible, worse than yours. In my case the cause was a crankshaft bearing which failed and filled one end of the motor with bits of shrapnel.

[@TheRebelOne.]

Rotax engines should be put into lawnmowers and not airplanes.......!

[@flexairz]

Regarding the two strokes, you're correct.. the four strokes are great for aircraft.

[@williamharris1302]

Would be a good reason not to finish the lawn.

[@Bartonovich52]

No. They should all go into lawnmowers. Liquid cooling systems, dog clutches, and gear boxes don’t belong in modern light aircraft. Especially not if the engine doesn’t have any better power to weight than a direct drive Continental based on an *_80 year old_* design!!

[@mikewilley5678]

Bartonovich52 that’s an opinion not supported by operational facts on the 912. 10 years and 1500 hours on three of them give me a different opinion..

[@destroytheilluminati770]

I have over 1,000 hours behind 2 stroke rotax with 0 issues, its usually the operator who is unfamiliar with operating characteristics of 2 strokes that have problems, personally id rather have the power and simplicity and lightness of a 2 stroke over the much more complicated 912/914 series. If you dont have a clue how to set up and fly behind a 2 stroke, then you have no business flying at all

[@bobosmarius5072]

I never trust needle bearings on two stroke piston pin. There is always place for fatigue. If the engine it will not be exploited above 4000 rpm, a bronze bushing it should be a much better choice. Although a bronze bushing will generate little more friction, it will not shatter and it would resist at shocks much better.

[@adamedward205]

Yep you should not use rolling element bearings for oscilating loads - that are significantly less than a 1/4 the rotation of the bearing unless in a supplied lube application, the rollers going back and forward over the same spot disipate the lubricant and its then a short time till failure, i see this exact fault time and time again in print equipment, can't believe a aeroplane engine would do that, its just dumb. As is no cages - full complement needlde bearings, the rollers go slightly side ways and twist in the bore then get snapped on load reversal, as they break up they push out as in this video and destroy any close moving parts they encounter.

[@nimrodquimbus912]

Good idea, A bushing will start making noise when it wears, not sudden catastrophic engine failure like that needle.

[@Errol.C-nz]

I'd have to say...not a full set of needles on that wrist pin...& yeah, go for caged bearings...have to agree with signs on detonation...shouldn't have that level of deposits or...its done a lot more hrs, by the look of the "good" barrel wear

[@Rfster900]

What I'd say? Well, that's a combustion engine. It's called "hardware" and, as is the case with any mechanical or electronic device, sometimes they fail. That's unfortunate and that's not even fair, I understand. But that's the nature of things. Someone famous once wrote: "Hardware eventually fails, software eventually works."

[@Flightstar]

That engine has not been operated or maintained properly, and that is an understatement.

[@ew4096]

ROTAX engines are the worst. Don't know why Americans install them in their craft. There are other lighter, more HP and more reliable engines than ROTAX. Also for an engine with such high price, one would think it might be constructed with better materials. However, don't know how many hours this particular engine ran. JUST DON'T BUY ROTAX. - PERIOD!

[@sonovabeach]

Detonation. Low octane fuel or lean cylinder...or both.

[@peanutbutterisfu]

The one cylinder was running lean which overheated the piston causing the top of piston to melt. When a piston overheats it expands causing the “scratches” on the side. I personally would never ever ever run a 2 stroke engine in a plane 4 stroke or nothing.

[@markhilken7026]

What do I think ? Very simple, CERTIFIED 4 stroke aircraft engines

[@garypeatling7927]

Modern two stroke oils are more concerned with smoke reduction than lubrication always look for bit oil smoke coming out exhaust

[@barrywhitley2535]

I don't think I would risk my life to a Rotax. Loads of reports of bad reliability and poor workmanship.

[@sharedknowledge6640]

What do you expect from a Rotax? They're mostly high strung poorly designed engines that favor power and light weight over reliability. If anything goes even slightly wrong they tend to quickly self destruct. They regularly and catastrophically fail in aircraft, watercraft, snowmobiles, and kart applications. BRP Rotax doesn't seem to care as they have relatively little competition in many markets. If you have anything powered by a Rotax never bet your life on it.

[@davet231]

Pre ignition big time scoring from when the bearing packed it in. I'm sure you did off video but test the bearings under some "load" from your hand that way you feel any chewy spots.

[@angelreading5098]

Why is it that we have vintage engines from 1936 still in service and yet too many modern engines are failing ? surely technology has moved on making them more reliable but apparently not ? as for loose needle bearings that are capable of migrating ! words fail me.

[@larkinflight]

Sh..t happens.. What was the cost of the overhaul?

[@Olle1975]

larkinflight We changed the main-engine, the C22 fly's again a week later. This engine is still available :-)

[@clayz1]

TD for the music. Should have done the whole thing like the intro.

[@michaela.660]

Severe pre-ignition and detonation leading to cylinder to piston overheat causing piston seizing at the crown. If this occured in a diesel or other high power 6-12 cylinder engine it would have pulled the crown of the piston off the rest of the piston at the first ring groove. Rotax will Rotax your ass into the ground/ they are great for use in jetskis, as long as you have oars and locks installed.

[@conantdog]

I'm guessing lubrication failure made those pins dislodge, just a thought I'm not an engineer but I've had many dirt bikes.

[@terrystearns9463]

Looks like your "friend" didn't take very good care of his engine

[@Olle1975]

Yes, but now he get's enought lessons to keep it care :-)

[@EamonnSeoigh]

It’s taken a whole lot of time for me to trust Rotax. But, they’ve been in the aviation business long enough to get things right through certification processes, so maybe I should lighten up. I need to get up in a Kitfox and see how they do before I form a new opinion.

[@onthemoney7237]

Four stoke clean oil it’s cheap good oil and water flow and warm up . Two stoke mix oil and gas your self than you know what you got 40 to 50 To 1 depending on who you talk to if plugs start fouling stay closer to 50 to 1 and warm up . Oil is a good thing mix correctly 🤙

[@HM-zu6lu]

Your engine suffered from overheating due to lack of cooling fluid, which causes the parts to expend untill there is no clearence at all! The two-stroke lubricant where boiled and disappeared due to the high temperature of an partly uncooled engine. When the piston expanded due to overheat it "welded" itself to the cylinder barrel and once an aluminium piston have done that it seizes again and again even with excessive lubrication, appearently the small end needle cage bursted due to a seized piston or overload far more than the designed force as a result of the seized piston which in turn caused the needle cage to burst and the bits falled down in the lower part of the crankcase, damaging the rotary inlet valves, then being blown through the side channels up on top of the piston. Appearently some engines seems to suffer from running flat out on snowscooters and other leasure equipment over longer periods, - they are not "bullet proof" as an old Bukh og Lister diesel! Others here on you tube have the same problems with needle bearings on Rotax big-ends worn out after use, maybe the design is on the lower side ie: underdimensioned. Make sure that the cooling system is completely full of cooling fluid and bleeded whenever possible, use a bit more two-stroke mixture than the makers state in the instruction book and run the engine with a modest load when flying. Should the same thing happen again, you could look into another engine, perhaps a Dmotor type 26, anyway; Good luck! Henning.

[@aviatrix2]

Uh. Nothing out of the ordinary on the pistons? I don't think so. Those have had severe FOD or shrapnel damage.

[@eugeneoreilly9356]

Never ever depend on the oil injection system on any 2 stroke engine and especially one used for aviation.Always pre mix the fuel.

[@waltersobchak9427]

The lesson here is Rotax engines are junk and they are a horrible company to work with. I've heard countless horror stories.

[@codycrawford2059]

I think its a rotec don't fly with it if you value your life and plane

[@TechnikMeister2]

That dear friends is a catastrphic engine failure. BMW were looking to outsource engines for its low range enduro bikes and turned to Rotax. In the end they gave up due to basic design flaws and component failures. These should never be considered for an aircraft. There is a reason why aircraft engines are designed with separate cylinders, aircooled, are relatively slow revving and offer double redundancy on ignition and fuel delivery...relaibility. I also see people who buy outrageously overpriced $100k "sports" planes with Rotax engines and try to run them on 87 RON ethanol fuel. 100 Avgas please.

[@conantdog]

I would have to agree friends don't let friends Fly 2 Strokes or Drive Green Tractors.

[@fieldsman3307]

hi Olle, my best guess would be a failure or incorrect fitting of the retaining circlip for the piston pin bearing....one thing is certain though which is that if you fly with a Rotax two stroke up front then it's a case not of if it will fail but when LOL

[@Olle1975]

I can't confirm, provide you fly a 582 in his temps, it is a very reliable engine!

[@seangreene64]

You had a wrist pin bearing failure. Check the oil feed line to that cylinder. Worked on rotax motors for years Seen this before. Typical two stroke failure.

[@reedsilvesan2197]

the word I'm trying to get across to this robot is detonation not definition as in my to previous posts voice recognition sometimes sucks

[@fredferd965]

You should never, ever attempt flight behind an engine that has let you down even once. They don't repair themselves, and the problems don't go away. As for engines....Lycoming and Continental.... engines you may rely on.

[@mmichaeldonavon]

I've never liked the 582 - WAY to many problems. Have cold seizures and hot seizures - coolant cavitates in the block. Never would use one. The 582 is the result of improper maintenance - wrong oil - wrong fuel/oil ratio, etc. All Operator Error.

[@davideskelin8266]

Didn't I read of another Rotax powered airplane losing power in the UK awhile back on take off and was able to abort take off? Also, t Your music was unpleasant!

[@jeffery7756]

I bought a Rotec Throttle body for my Ranger engine. It doesn't work. I tried contacting Rotec for customer support several times ... no reply. Rotec is a waste of time and money.

[@garyweber4333]

i'v had these issues it all starts with bad fuel or fuel delivery dirty carb next check for an air leak Rebuilt crank needed brass in center bearings feels fine now 5 hr its toast run premium auto gas no ethanol looks like that engine had some 100LL that's what the scale looks like

[@charleswesley9907]

2 cycles are 2 sensitive to fuel mixtures or heat and turn high RPM which isnt that good for reliability . When your life depends on it a simple half VW will not fail you and take your life . The Half VW isnt as powerful but is plenty for this app.

[@mmichaeldonavon]

That's a 582 - would NEVER fly one of those. The 503 IS the engine and is bulletproof.

[@Olle1975]

My runs amazing since 8 years.

[@argoiiisailingyacht2400]

I had seedoo jet ski with rotax engine. Strong engine but soon with many problems.

[@Olle1975]

ARGO III Sailing Yacht I fly 582 greyhead since 6 years with 230 hrs without any problems, the engine itself is 28 years old, I love it.....👍

[@argoiiisailingyacht2400]

Olle1975 I think it was very good your engine. For me I prefer rolls Roy’s

[@davestevens7386]

Looks like your running Pensoil or some similar junk. I've been using Red line synthetic for over 30 years and have over 10,000 hours in 277,377, 447, 503, 532, 582 and 618 Rotax. Over $50/gal and worth every penny.

[@ringgo1star]

That's awesome! Were all the engine used for flying?

[@davestevens7386]

@@ringgo1star of course. Mostly in Quicksilver.

[@ringgo1star]

How many hours & failures on the 582? That's what I'm flying.

[@reedsilvesan2197]

Dave Stevens hey Dave I see you're running Red Line in your rotax engines I just got one I'm also running Red Line but I bought the racing oil is 90 bucks a gallon which one are you running because I wouldn't mind spending a little less jingle on my oil

[@gerdesoto262]

The people that talk about that rotex engine failure and others are air cooled engine and makes a very good boat anchor. no air cooled engine has the durability and reliability of a V8 engine and a V8 can be put on a Airplane and work well on a Airplane, but requires some imagination and modifications to get it to work well, no air cooled engine will stand up against a V8 car engine. and the V8 has a great history in reliability and durability, plus you can see the car engines on small Airplanes here on KZbin. The people that has the failures with air cooled engine change them junk engines out for a V8.

[@Olle1975]

Ger Desoto Rotax is a watercooled Engine!

[@gerdesoto262]

@@Olle1975 but not reliable and dependable against the V8 car engine. There is alot stories about people having these small Airplane engines that come from the factory, and to many of them are failing. and the airplane accident and deaths are happing because the engines are junk in the first place there is alot of stories on KZbin now about these engines. that on small Airplanes and failing, all because they never had the reliability and durability built in them in the first place, verses what's happened to a car engine with decades of experience from the public and more.

[@gerdesoto262]

@@Olle1975 but there is to many of them Rotax engines falling apart plus they are made in Australia. They don't have the reliability and durability of a V8 engine. the engines that are been used on small Airplanes should end main reason the principal technology has ben used since the 1930s and no major change since then to now and major improvements. The V8'S has gone through the improvements for reliability and durability and that's why a car engine V8 is a better engine for airplane. History doesn't lie for nobody anywhere anytime and for any reason.

[@clintonstewart4786]

This engine didn’t fail it was killed! Improper warm up and looks like very poor carb adjustment! Treat it right it will run double it’s tbo with no problem!

[@NihongoGuy]

Rotax engines are not aviation engines, they are a glorified snow mobile engine. Trusting your safety to a Rotax is questionable at best.

[@crowmagg1]

Lean cylinder

[@brandonquenneville7330]

carlos has it right most likely

[@garymaxfield7120]

Brandon Quennville: I agree

[@r08800]

Unless a person here is a LAME or AME then it doesn't matter what WE think. I'm sure people have died due to someone taking armchair experts advice.

[@eenbeenman]

The music is intrusive and serves no purpose, contributing nothing to the story.

[@FlexxVision]

This engine is total down, buy an new one.. the time is over for this very old or oil less engine..

[@williamharris1302]

I would not put a rotex on a lawnmower.

[@reedsilvesan2197]

William Harris rotax wouldn't fit on a lawn mower lawn mowers at vertical crankshaft rotax is a horizontal crankshaft

[@jeffreyhagelin6047]

Cage less needle bearings ? Replace with conventional bearings. Problem solved.

[@fremountstsongsrich2453]

1 ? When is the FAA going to outlaw Rotax for any Any type of Aircraft too many problems to many pilots hurt or killed and way too many Airplanes wrecked when when When????,,

[@alyn7d7]

No I really never seen anything good about Rotax Engine

[@darylbuckner5596]

Except their hundreds of thousands of hours flying & sledding.

[@Jim.Thunda]

Too much carbon deposit, excessive EGT, long idle times at wrong mixture (far too rich) Probably wrong oil in fuel mix. Just bad operating technique, but there not called Austrian grenades for nothing.

[@pilotpeego1820]

Lose the music!

[@onthemoney7237]

Turn off your volume lol

[@ralphkrause1766]

Narration instead of music tnx R

[@davidrobertson8035]

too lean

[@MrInTheWind]

Sorry rotec

[@Olle1975]

Rotax!

[@Janne1Hirmu]

Horrible music

[@autonomous_collective]

There are several different signs pointing at lubrication failure. That engine also shows high service time. My guess is either the oil separated in the tank, over time, or it was running too lean. Another reason to always use high spec full synthetic 2 stroke oil as the lubrication stability for extended time in the mixed state(Amsoil is the best). Modern fuel additives can attack mineral oil film strength over time. The lean state results in pre ignition which hammers the small end bearings. Forensic examination for surface discolouration or patterning will point to which fault caused them to fail, along with the cage.

[@reedsilvesan2197]

Autonomous Collective I don't agree that atoms oil is the best red line is by far the best oil you can buy I run their racing oil 90 bucks a gallon