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I had an oil ring stick on my #5 cylinder which pumped overboard through the air oil separator almost 5 qts after a four hour trip at 13000! Landed and oil was dripping from tail tie down! Engine is over tbo at 2375. All compression good except no 5 at 60. Thinking about ordering rebuild from cont in near future! Any thoughts! 

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So, you need to remove the cylinder anyway, your engine will need an overhaul sooner than later, if the cylinder isn't scored, replace the piston and rings and have the cylinder honed. Why buy a new cylinder if you don't need one?

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Cylinder #5 is a case by itself…

It is the one that runs hotter than the others on the LBs with IO550s…

How many hours do you have on that cylinder?

If you got 2k hours out of it, you did well.

Got any JPI data to review?

Did you have any hint that your oil was being evacuated?

See if @M20Doc has seen this before… (IO550, broken oil ring, oil sent overboard, plane landed safely… no other issues, looking at next steps)

Best regards,

-a-

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The 550 series engines are the only ones that I’ve seen stick rings,  I don’t have an answer as to why they do.  Pull the cylinder for repair, examine the engine internals to determine what’s next.

Clarence

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29 minutes ago, M20Doc said:

The 550 series engines are the only ones that I’ve seen stick rings,  I don’t have an answer as to why they do.  Pull the cylinder for repair, examine the engine internals to determine what’s next.

Clarence

I recently had a stuck oil ring on #5  - at 1400 hrs on my 550. Blow by and burn at 1Q / 1.5 hrs. I echo @carusoam - if you got 2000 you did well.

 

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I think I've read about stuck rings in a Lyco 540 in a TB20, but the owner flies it really high, which results in low power settings. I also recall reading something about a flush with a good automotive oil for the last few hrs before an oil change - but that was on a low hours engine.

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On 7/27/2021 at 5:43 AM, tmo said:

I think I've read about stuck rings in a Lyco 540 in a TB20, but the owner flies it really high, which results in low power settings. I also recall reading something about a flush with a good automotive oil for the last few hrs before an oil change - but that was on a low hours engine.

Doesn’t modern automotive oil react negatively with leaded fuel combustion?  I thought I read that somewhere that is why we don’t run PAOs and ester based synthetics in airplanes.

Edited by arikanoandy
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I believe the main problem with running automotive oil in airplane engines is due to the metallic anti-wear agents in the automotive oil additive package. Aircraft engines have wider tolerances and burn a lot more oil than auto engines. The additives in aircraft oil are designed to be ashless so as to not leave metallic ash in the cylinders which can cause preignition.

Skip

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3 hours ago, arikanoandy said:

Doesn’t modern automotive oil react negatively with leaded fuel combustion?  I thought I read that somewhere that is why we don’t run PAOs and ester based synthetics in airplanes.

Yes, hence it is used as a "flush" (diluted in the proper aircraft oil and for a short period of time) and not as a routine application.

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There is a popular OIl Control RIng Flush solvent provided by Ed Kollin, the guy that invented the oil additive for Exxon and Camguard. But the engine is never operated with the flushing solvent. The engine is drained of all oil and then the cylinder while at Bottom Center is filled  through the top spark plug hole. The top plug is then replaced and you manually create a hydraulic lock by turning the prop by hand till you feel the resistance. Next you apply continuous pressure to force the flushing fluid through the rings. It may take three or 4 times till you can hear the fluid squirting past the rings which is your indication that the ring is clear.  Then drain any remaining fluid and complete the oil change with fresh oil and filter.

Ed's recipe: 1 gallon of Varsol (mineral spirits), 2 qts MEK, 2 qts Xylene, 2 qts Aeroshell W100

It doesn't always work, and some stubborn rings will benefit from soaking in the flush fluid overnight. 

Edited by kortopates
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MMO or Marvel Mystery Oil is an old remedy, it is NOT approved for aircraft, but I have seen a few radials that will stick exhaust valves without it.

‘I believe there is evidence that’s it’s nothing but mineral spirits, some red dye and peppermint oil or similar for the smell, so it’s definitely snake oil. but I’ve seen it work more than once.

As easy as it is to pull a cylinder though, I’d pull it or at least bore scope it, it’s probably well beyond fixing by any flush procedure.

MEK is likely not friendly on seals and gaskets, I’d be wary of it.

Issue of going well past TBO isn’t that you can’t, it’s that if you do it’s likely to be a very expensive field overhaul, if you go well beyond TBO, maybe a factory exchange motor is the best way to go

Edited by A64Pilot
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On 7/28/2021 at 5:03 PM, kortopates said:

 

Ed's recipe: 1 gallon of Varsol (mineral spirits), 2 qts MEK, 2 qts Xylene, 2 qts Aeroshell W100

It doesn't always work, and some stubborn rings will benefit from soaking in the flush fluid overnight. 

Varsol is Exxon's brand name for mineral spirits....   I think charcoal lighter is the stuff that they don't know what to do with so they bottle it up and sell it to the general public.   Prove me wrong there are not ingredients listed on the package. 

 

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3 hours ago, Yetti said:

Varsol is Exxon's brand name for mineral spirits....   I think charcoal lighter is the stuff that they don't know what to do with so they bottle it up and sell it to the general public.   Prove me wrong there are not ingredients listed on the package. 

 

My favorite is odorless paint thinner. It's another name for mineral spirits -- but it doesn't stink.

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Stoddard solvent is also I believe Mineral Spirits, it’s also called White Spirit overseas?

Military Mil Spec solvent we used was called PD-680 AKA dry cleaning solvent, but I think it was nothing more than mineral spirits, looking it up, it’s known by a whole lot of different names depending on where in the world you are.

https://en.wikipedia.org/wiki/White_spirit

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4 hours ago, ArtVandelay said:

These days MEK is hard to find, there’s now “MEK substitute” which I assume is more environmentally friendly.

I think it is supposed to be less carcinogenic/toxic.   Supposedly if you buy larger than quart or gallon containers you can still get genuine MEK.    So far I've never needed the real stuff.

Varsol and Stoddard Solvent are brand/trade names for essentially mineral spirits.   I think both may have some other secret ingredients, but they don't seem to be enough to make much difference.   Stoddard Solvent was originally invented and marketed as a dry cleaning fluid, so it's nothing particularly special for mechanical/aviation use other than so many texts and references mention it rather than a more generic description.   Same with Varsol.   It's like saying "kleenex" when you really mean "facial tissue".   It just kinda adds confusion to some degree.

I haven't quite sorted out the "odorless" part of odorless mineral spirits yet.   I use it sometimes and it often has kind of a milky consistency which seems like it shouldn't be there.  

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Sooooo many organic solvents to select from…

If you see a milky cloud… that is probably some moisture or other substance that isn’t dissolving very well… but kinda staying in solution…

An alcohol likes organic molecules on one end and inorganic molecules on the other end…

So… an alcohol in your organic solvent helps dissolve water into the system… until so much water is absorbed in the system… it will turn cloudy…

I was looking up methylene chloride… I was thinking that was aka dry cleaning fluid…  didn’t get to a good reference though…

PP ideas about organic solvents only, not an organic chemist…

Best regards,

-a-

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