MMO or other oil control ring tricks?

[DXB]

In the last 50 hours, my oil consumption has gone from 1qt/12 hrs to 1qt/7 hrs.  Then the other day in cruise I  noted a slight vibration along with a high EGT on cylinder #4, which resolved after about 10 seconds.  Subsequent in flight mag checks were fine.  I assumed it was a transiently fouled plug on #4.  Because my Tempest UREM37BY plugs were past due for service and  had >450 hours on them, I replaced them all today and borescoped the cylinders at the same time.  Cylinders 1,2,3 had normal deposits on the plugs, and my borescope exam of cylinder wall and  the valves looked normal.  Notably the O-360-A1D engine is at 1100 SMOH, and cylinder #4 is the only one that hasn't been IRAN'd or replaced in the last few hundred hours.   Findings for cylinder 4 were as follows:  Slight oily residue was present on BOTH top and bottom plugs. It wasn't the worst oil on plugs I've seen, but still, any oil on the top plug pretty clearly indicates a problem. On borescope, the top of piston and cylinder walls on #4 were also more oily in appearance. There was no obvious scoring of walls to my eye, though I don't really have the experience to detect this - the walls for #4 definitely looked very different because of the extra oil. I think #4 is almost certainly the culprit behind increasing oil consumption, which really isn't that bad yet.  The #4 valves look normal. Pulling the prop through on #4 was no softer than the other 3, and so I bet it would pass a compression check.  I don't see any hard criteria to pull #4 at this point, but I also don't like oily fouled plugs and vibrations in flight.  Questions:  Is this the so called "stuck oil control ring" type situation on #4?  Are there tricks to remedy the situation without pulling the jug? I've read about mythic properties regarding Marvel Mystery Oil in this situation in the dark depths of the internet.  I am downright sick of doing cylinder work, which has mostly been for burnt exhaust valves, but the valves on #4 are still fine.  

[kortopates]

I prefer the direct approach. Their is a recipe for clearing a stuck ring that was developed by the Ed K the guy that designed Camguard. It includes solvent, camguard and more. The really cool thing about it is that when do the procedure you'll know whether or not you really have a stuck ring, since it will create a hydraulic lock in your cylinder. Then you'll know when you've succeeded when the hydraulic lock clears and its totally non-invasive. Google the internet and you should be able find it. In another recent thread here on MS, i pointed someone to a thread on Beechtalk discussing it. The technique is usually successful but won't fix a broken ring of course which could be a possibility but you indicated a clean borescope of the cylinder walls.

[DXB]

thanks - interesting - this is what I found:

https://www.scribd.com/doc/254085919/Oil-Control-Ring-Solvent-Flush-Procedure-Ed-Kollin-CamGuard

 Seems a bit too involved to do on my own - particularly the part about removing the quick drain and re-O-ringing it.  Will talk to the A&P.   

I was hoping for a safe do it yourself first step, and found this thread on Beechtalk:

https://www.beechtalk.com/forums/viewtopic.php?f=37&t=84342

Specifically Don Lawrence's suggestion:

"Direct application of Marvel Mystery Oil into the cylinder often works to free up stuck rings. You have to bring the cylinder up part way on a compression stroke, remove the top plug and then fill the cylinder with MMO. Re-install the plug, bring the piston on up until it hydraulically locks and rock it a little with your arm to work the MMO into the rings under pressure. Obviously this is a job totally using muscle power. Do one cylinder at a time. To help improve chances, let the cylinder sit with the MMO charge overnight or longer before sucking the MMO out through the top plug and using it on the next cylinder.

You can assist your A&P while doing the procedure. Caution, he and others may laugh at the process. When it works and he does not get paid for removing the cylinders the laugh might evaporate."

I was just going to do this procedure for the offending #4 cylinder except just drain it out the bottom plug hole when done, then add another ~10% volume MMO to the oil, do a ground run, and then change the oil.   Perfectly safe?  Useless?  Dangerous "hold my beer" move by someone with limited mechanical ability?

Edited August 5, 2019 by DXB

[kortopates]

Ed's recipe has proven to be pretty effective. When done, its all drained out and fresh oil is added back into the crankcase. We don't recommend adding unapproved MMO to the crankcase and running the engine on it. 

[Yetti]

seems like if you are going to the trouble might want to wash the valve guides down in MMO and melt out some of the gunk.

[bradp]

I’ve used the MMO method to unstick a control ring.  It worked for me .  I don’t have experience with Ed’s method.  

[orionflt]

18 hours ago, DXB said:

In the last 50 hours, my oil consumption has gone from 1qt/12 hrs to 1qt/7 hrs.  Then the other day in cruise I  noted a slight vibration along with a high EGT on cylinder #4, which resolved after about 10 seconds.  Subsequent in flight mag checks were fine.  I assumed it was a transiently fouled plug on #4.  Because my Tempest UREM37BY plugs were past due for service and  had >450 hours on them, I replaced them all today and borescoped the cylinders at the same time.  Cylinders 1,2,3 had normal deposits on the plugs, and my borescope exam of cylinder wall and  the valves looked normal.  Notably the O-360-A1D engine is at 1100 SMOH, and cylinder #4 is the only one that hasn't been IRAN'd or replaced in the last few hundred hours.   Findings for cylinder 4 were as follows:  Slight oily residue was present on BOTH top and bottom plugs. It wasn't the worst oil on plugs I've seen, but still, any oil on the top plug pretty clearly indicates a problem. On borescope, the top of piston and cylinder walls on #4 were also more oily in appearance. There was no obvious scoring of walls to my eye, though I don't really have the experience to detect this - the walls for #4 definitely looked very different because of the extra oil. I think #4 is almost certainly the culprit behind increasing oil consumption, which really isn't that bad yet.  The #4 valves look normal. Pulling the prop through on #4 was no softer than the other 3, and so I bet it would pass a compression check.  I don't see any hard criteria to pull #4 at this point, but I also don't like oily fouled plugs and vibrations in flight.  Questions:  Is this the so called "stuck oil control ring" type situation on #4?  Are there tricks to remedy the situation without pulling the jug? I've read about mythic properties regarding Marvel Mystery Oil in this situation in the dark depths of the internet.  I am downright sick of doing cylinder work, which has mostly been for burnt exhaust valves, but the valves on #4 are still fine.  

Dev,

If you want to swing by one weekend we can look at it and try a few non invasive options. 

Brian 

[Ragsf15e]

I’m in the exact same situation here with an IO-360.  Oil use went from 6 hrs/qt to 3.5 over a couple flights (chrome cylinders, so 6/qt was just fine before).  

No indication from the engine monitor.  Egt and cht looks the same as before.  Mag checks are good.  Exhaust might be a bit oily or it’s just me.  Performance seems normal too.  I’m about to start down the trail of checking the plugs and borescope to figure out which one it is.  2 newish cylinders, 2 x 900 hours cylinders due to the same exhaust valve issues as the OP.

Heres to hoping not to pull another cylinder!

[DXB]

So some followup on this situation - with a little help I pulled the top plug on the problem cylinder (#4), filled with MMO with it near TDC, reinstalled top plug and rocked prop back and forth a few times to try to push some solvent past the rings, and then drained the stuff out.  We then added 1qt MMO to the oil, flew for 5 hours, and then changed the oil.  

So fast forward 40 hours and my next oil change - Oil consumption stabilized, reduced slightly at 1 qt per 8-9 hr. No more plug fouling events on #4. And no more oil found on either top or bottom #4 plug and only healthy tan deposits on them. Much less oil pooled inside cylinder on borescope.

I'm gonna tentatively say that the MMO trick worked, and I am tentatively happy.  It's best not to gloat here, lest the aviation gods strike me down for my arrogance  at next oil change by shredding my cam into my filter 

Edited November 4, 2019 by DXB

[ArtVandelay]

I use MMO on my pre oil change flight, it seems to prevent stuck valve syndrome as well. I personally don’t like it in my oil as a regular additive. Add it, fly it, then change it.


Tom

[tmo]

I seem to recall reading of people successfully fixing stuck ring issues (blamed on, iirc, too much low power flying - na engine up high) by adding a fully synthetic automotive motor oil (Mobil 1 0W20) to the sump a few hours before an oil change.

 

[ArtVandelay]

I seem to recall reading of people successfully fixing stuck ring issues (blamed on, iirc, too much low power flying - na engine up high) by adding a fully synthetic automotive motor oil (Mobil 1 0W20) to the sump a few hours before an oil change.
 

Probably comes from fact they sometimes have additives for cleaning, like they do with gas. Synthetic oil doesn’t handle avgas additives (lead) very well. That’s why I like to do one 1 flight and then change the oil.


Tom

[Andy95W]

8 hours ago, ArtVandelay said:

I use MMO on my pre oil change flight, it seems to prevent stuck valve syndrome as well. I personally don’t like it in my oil as a regular additive. Add it, fly it, then change it.


Tom

Just curious, how much do you use for that flight?  

[ArtVandelay]

Just curious, how much do you use for that flight?  

1/2 quart normally, I used a full quart after a morning sickness episode.


Tom

[jetdriven]

Berrymans B12 Chemtool is also an effective solvent to flush the rings with.  

[RobertGary1]

I think you're asking for trouble pooring non-approved substances into your engine. Legally it has to be an A&P who puts in additives that aren't MIL spec'd for your oil .

In my experience the best solution is to just pull the jug back and inspect the ring and check the round of the cylinder.

-Robert

[orionflt]

2 hours ago, RobertGary1 said:

I think you're asking for trouble pooring non-approved substances into your engine. Legally it has to be an A&P who puts in additives that aren't MIL spec'd for your oil .

In my experience the best solution is to just pull the jug back and inspect the ring and check the round of the cylinder.

-Robert

I prefer to use other methods before I pull a jug! that includes compression tests and bore-scoping the cylinder.  in most cases if there is no damage using things like MMO can free things up and avoid the expense and possible other issue associated with jug removal. Even the engine manufactures agree that removing the jug should be the last thing you do.

[Andy95W]

23 minutes ago, orionflt said:

I prefer to use other methods before I pull a jug! that includes compression tests and bore-scoping the cylinder.  in most cases if there is no damage using things like MMO can free things up and avoid the expense and possible other issue associated with jug removal. Even the engine manufactures agree that removing the jug should be the last thing you do.

+1

A&Ps were using Marvel Mystery Oil back in the 1940s, 50s, and 60s with good results. Our engines are 1940's technology.  That's pretty much good enough for me.

ISTM this falls into the category of, "If it's stupid, but it works, then it's not stupid."

[DXB]

2 hours ago, RobertGary1 said:

I think you're asking for trouble pooring non-approved substances into your engine. Legally it has to be an A&P who puts in additives that aren't MIL spec'd for your oil .

What kind of trouble?  By what mechanism? Though my enthusiasm for MMO's marketing is tempered by skepticism, the stuff has been around almost a century with hardly any anecdotal evidence of harm when used in the described applications. By contrast, ability of this solvent to unstick an oil control ring is entirely plausible and likely what happened in my case, whereas I am not aware of any rational basis to think washing out a cylinder with it might cause harm. By contrast, the substantial risk of invasive maintenance on an engine are well established, and if MMO helps prevents needing to do so, I don't care about the "legality" of a hangar elf having exposed my engine to the stuff briefly without mentioning it in the logs.  

[RobertGary1]

2 minutes ago, DXB said:

What kind of trouble?  By what mechanism? Though my enthusiasm for MMO's marketing is tempered by skepticism, the stuff has been around almost a century with hardly any anecdotal evidence of harm when used in the described applications. By contrast, ability of this solvent to unstick an oil control ring is entirely plausible and likely what happened in my case, whereas I am not aware of any rational basis to think washing out a cylinder with it might cause harm. By contrast, the substantial risk of invasive maintenance on an engine are well established, and if MMO helps prevents needing to do so, I don't care about the "legality" of a hangar elf having exposed my engine to the stuff briefly without mentioning it in the logs.  

Warranty issues, FSDO inspector walking up behind you, and just the untested nature with the unique chemistry of aircraft engines. I'm sure MMO wouldn't endorse using this in an aircraft too.

By the way; In car engines I've found MMO soaking to be useless in freeing rings. Maybe it worked for someone at some point but of those of us who've had stuck oil control rings in cars, I've not found 1 person to say it helped.

Not saying you'll fall out of the sky, just saying I wouldn't do it to my engine.

-Robert

[EricJ]

People have been pouring MMO into airplane crankcases and fuel tanks with great regularity for many, many decades.   If it were causing great harm there have been multitudes of bundles of opportunities to discover it and note it and write SIs or SBs or ADs or whatever.    Instead of that sort of thing, instead you have a lot of old, grumpy, grey-haird, experienced A&P/IA/pilot/builder/whatever folks sharing wisdom on how to use it properly to get it to do what you want to help diagnosis or save a ton of money on unnecessary maintenance.

That's my take on it, anyway.

But, yeah, it's not necessarily "approved" anywhere. 

[EricJ]

4 minutes ago, RobertGary1 said:

By the way; In car engines I've found MMO soaking to be useless in freeing rings. Maybe it worked for someone at some point but of those of us who've had stuck oil control rings in cars, I've not found 1 person to say it helped.

Usually in cars it's SeaFoam. 

[N201MKTurbo]

Don't worry, I won't rat you out for using MMO to un-stick rings.

Considering all the unapproved lubricants I see A&P using all the time, I hardly think this is the top of the list for busting people. If I had a warranty issue with my engine, I wouldn't go telling the engine shop "It was working great until I put MMO in it" besides who puts MMO in an engine that is still in warranty? MMO is for old engines that you are trying to get a few more years out of.

[Andy95W]

19 minutes ago, RobertGary1 said:

FSDO inspector walking up behind you, 

Two of the maintenance inspectors at my FSDO own their own airplanes.  They would be more interested in MMO use for their own airplanes than for any type of enforcement action.  They would probably recommend its use, in fact.  They might even suggest it's use in flight (off the record, of course.)

I still think putting it in avgas is dumb in any airplane that wasn't designed to run on 80 octane.

[ArtVandelay]

There are YouTube videos where a guy adds it, runs the engine, and compares before and after. It definitely looks like it cleans the engine.
As I said, I use it for 1 flight, then change the oil right afterwards, don’t leave it sit, I definitely would not use in our fuel tanks, I’m afraid what it would do to the sealant.


Tom