Lycoming Stuck Ring?

dell30rb said:
I might try the MMO if the mechanic is on board with it.

The original quote of $1400 seems pretty high. I'm guessing that is for a full cylinder overhaul. I'd think to just pull the jug and replace a set of rings should be about $150 in parts and 3 hours labor?
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The head of maintenance wants to do the MMO. The chief mechanic (who I take duck hunting) thinks the MMO is a Snake Oil solution. Funny how you get two different opinions from the same shop.

The cylinder R&R is 10 hours. Perhaps the turbo and all that make it more time consuming. I am going to find out after the borescope test what my options are with the cylinder. I would like to avoid a full rework on a 550 hour cylinder if not required.
 
If the cylinder's damaged, then the decision is made for you. If it's not, do you really think another couple of hours is going to do it in? Your temps are within spec, right? Your filter and screen are clean? It's your money, and if it's burning a hole in your pocket, the by all means spend it.

But sometimes, snake oil works.

Ymmv.
 
Hmmmm. Risk this type of failure on a $100k+ turbocharged airplane that runs the engine under heavy loads or spend $1.5k and get it fixed? Roll the dice...



This was about 500 SMHO from a brand name shop on a tiny O-320.
 
dell30rb said:
I might try the MMO if the mechanic is on board with it.

The original quote of $1400 seems pretty high. I'm guessing that is for a full cylinder overhaul. I'd think to just pull the jug and replace a set of rings should be about $150 in parts and 3 hours labor?
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That was my suggestion if the cylinder isn't damaged. May as well pull the valves and clean them and the seats as well.
 
No matter what you do someone somewhere could have -
  1. Fixed it with a mechanic in a bottle
  2. Run it 50 more hours
  3. Fixed it 50% cheaper and 75% faster
:goofy:
 
If the repair is really going to take 10 hours and cost $1500 I would MMO it as mentioned above. Go fly an hour and have the pressure test done again on the cylinder that failed it. If it passes, the ring was just stuck, its free now and you spent less than $100.

However if you can get an intermediate solution that will fix the problem for good, i'd go with that. The plane is already in the shop, if you can have a new set of rings slapped on for $500 i'd probably pick that option. At that price, its not worth your time trying the MMO and hoping it works.

I wouldn't spend an extra grand to get a good cylinder w 500 hours and the valves re-worked.
 
Just FYI, but the Lycoming labor allowance chart says for a 6cyl turbo it should take 6 hours for first cylinder R&R and .25 for rings. Just a data point, not that it makes a huge difference.
 
bnt83 said:
Hmmmm. Risk this type of failure on a $100k+ turbocharged airplane that runs the engine under heavy loads or spend $1.5k and get it fixed? Roll the dice...



This was about 500 SMHO from a brand name shop on a tiny O-320.
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Interesting photo, but that sure doesn't look like the result of a stuck oil ring after an hour of service, and judging from the condition of that piston I bet a borescope exam of the cylinder an hour before that failure would have revealed some anomalies.

Look, I'm not a cheapskate when it comes to mx. But I have been led by the wallet down the garden path enough times to look at expensive recommendations with a jaundiced eye. Sometimes it's worth a shot at the cheap and easy when there's little downside and good upside potential.
 
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Chip Sylverne said:
Interesting photo, but that sure doesn't look like the result of a stuck oil ring after an hour of service, and judging from the condition of that piston I bet a borescope exam of the cylinder an hour before that failure would have revealed some anomalies.

Look, I'm not a cheapskate when it comes to mx. But I have been led by the wallet down the garden path enough times to look at expensive recommendations with a jaundiced eye. Sometimes it's worth a shot at the cheap and easy when there's little downside and good upside potential.
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Thing is once the oil control ring stars losing chunks of the spring and they get wedged under the compression ring and hot gas starts blowing by, the results in that picture are not far off. If they can hear the blow by, it's already starting.
 
Alexb2000 said:
m not trying to brag, but I keep the motor super clean as well as all of the inside cowlings. If there was an oil leak it would be obvious, especially 2 quarts of oil in last 8 hours.
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Do you see evidence that there are 2 quarts of oil in the last 8 hours that have blown out your breather? What does the belly look like?

I'm just not seeing enough detail in these posts to come to an absolute conclusion. Of course I'm not seeing it in person.

Just the fact that some air is leaking on the compression test and is coming out the breather is not a reason in itself to pull a cylinder. Where is the rest of the evidence confirming that the oil is going out there?
 
Henning said:
Thing is once the oil control ring stars losing chunks of the spring and they get wedged under the compression ring and hot gas starts blowing by, the results in that picture are not far off. If they can hear the blow by, it's already starting.
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Assuming the ring and expander are broken, not just sludged up, as coil type expanders are prone to do. Either way, you're going to get some blowby.

It'll be interesting to get the borescope results. I hope .jpg's are posted.
 
This thread is suffering from confusion as it seems there are two different things being discussed here. Initially the mechanic claimed that a stuck compression ring was causing combustion blow-by to pressurize the crankcase and force oil out the vent. Somewhere along the way someone began talking about a broken oil control ring which is an entirely different thing with an entirely different end result. The oil control ring carries oil up and down the cylinder and keeps the cylinder wall lubricated, it has nothing to do with compression or the sealing of the combustion chamber from the crankcase.

Regardless of any of this the absolute first thing that should be checked, which has already been mentioned, is that the oil/vapor separator is functioning correctly and that the separated oil is draining properly back to the sump. For one thing, make certain the drain tube is not kinked or clogged. Once that has been determined to be okay you can maybe start wiping the dust off the cylinder base wrenches but jeeze, slow down a bit and take the finger off the hair trigger here.
 
Well here's where I am. I called and spoke to Zepher engines cylinder head guy today. The issue is not so much the cylinder as the valves. Just the exhaust valve is $800 from Lycoming because it is sodium filled. Further they allow only .002" wear on the valve. If the valve has any wear out of spec. then it is cheaper to just buy a $2800 cylinder assembly, valves, piston, barrel. So basically sending a used cylinder in often results in the "opportunity" to buy a new assembly. With that knowledge, we took a little change of course.

They put MMO in the cylinder last night (couldn't hurt anything). Today after the above they cleaned the separator, cowling, belly, etc. and ran the engine to operating temp. The compression test after MMO was 74 (first test was 70). They say that running the engine that long there is no way the MMO is effecting the compression and that it did come up. Also NO oil out of the breather, on the belly, etc. Of course the real test is to fly it. So probably first of the week I will take it outside the B where I can get an unrestricted climb to at least 10K. We'll see what happens after that.

Stay tuned.
 
Alexb2000 said:
Well here's where I am. I called and spoke to Zepher engines cylinder head guy today. The issue is not so much the cylinder as the valves. Just the exhaust valve is $800 from Lycoming because it is sodium filled. Further they allow only .002" wear on the valve. If the valve has any wear out of spec. then it is cheaper to just buy a $2800 cylinder assembly, valves, piston, barrel. So basically sending a used cylinder in often results in the "opportunity" to buy a new assembly. With that knowledge, we took a little change of course.

They put MMO in the cylinder last night (couldn't hurt anything). Today after the above they cleaned the separator, cowling, belly, etc. and ran the engine to operating temp. The compression test after MMO was 74 (first test was 70). They say that running the engine that long there is no way the MMO is effecting the compression and that it did come up. Also NO oil out of the breather, on the belly, etc. Of course the real test is to fly it. So probably first of the week I will take it outside the B where I can get an unrestricted climb to at least 10K. We'll see what happens after that.

Stay tuned.
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Wow... That is one expensive cylinder assembly....:hairraise:
 
N801BH said:
Wow... That is one expensive cylinder assembly....:hairraise:
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While Lycoming significantly lowered the pricing on their standard parallel valve and angle valve heads (as well as the "fish eye" Navajo cylinders) due to competition from PMA'd cylinders, the 390/580 and -AJ1A have no PMA'd parts yet, and so the prices are really high. Given that the only engine that uses that cylinder design is the -AJ1A and there are relatively few of those engines out there, expect the price to stay high.
 
Henning said:
Thing is once the oil control ring stars losing chunks of the spring and they get wedged under the compression ring and hot gas starts blowing by, the results in that picture are not far off. If they can hear the blow by, it's already starting.
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YGTBSM, parts of oil rings rings getting caught under compression rings. How would they get there? the side clearance of the compression ring is .002" how would a piece of any thing get in there?
As a compression ring wears the cavity behind it fills with hard carbon. ain't nothing going to get in there.
 
Alexb2000 said:
Well here's where I am. I called and spoke to Zepher engines cylinder head guy today. The issue is not so much the cylinder as the valves. Just the exhaust valve is $800 from Lycoming because it is sodium filled. Further they allow only .002" wear on the valve. If the valve has any wear out of spec. then it is cheaper to just buy a $2800 cylinder assembly, valves, piston, barrel. So basically sending a used cylinder in often results in the "opportunity" to buy a new assembly. With that knowledge, we took a little change of course.

They put MMO in the cylinder last night (couldn't hurt anything). Today after the above they cleaned the separator, cowling, belly, etc. and ran the engine to operating temp. The compression test after MMO was 74 (first test was 70). They say that running the engine that long there is no way the MMO is effecting the compression and that it did come up. Also NO oil out of the breather, on the belly, etc. Of course the real test is to fly it. So probably first of the week I will take it outside the B where I can get an unrestricted climb to at least 10K. We'll see what happens after that.

Stay tuned.
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You best hope there isn't a broken ring in there, or you get to buy a whole engine, crank and every thing.
 
Tom-D said:
You best hope there isn't a broken ring in there, or you get to buy a whole engine, crank and every thing.
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Tom-

How would you know if there was a broken ring conclusively? The compression is now 74, no blow-by, borescope good, and three compression tests. These aircraft repairs are so frustrating, there seems to never be agreement on anything.
 
Alexb2000 said:
Tom-

How would you know if there was a broken ring conclusively? The compression is now 74, no blow-by, borescope good, and three compression tests. These aircraft repairs are so frustrating, there seems to never be agreement on anything.
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If it really broke a ring........... there WILL be parts falling out of the sump during the next oil change and /or lodged in the filter and in the oil analysis report as higher suspended metals........
 
I had two calls in the last month about sudden high oil consumption on the Lycoming TIO540 engine. So much consumption that they landed with very little oil. In both cases it was a broken oil control ring. Sudden consumption has been a bad turbo many times too, oil loss is so fast in those cases. This problem has been going on since the introduction of the new chrome edge cast iron oil control rings in 1994, So many times the people that where forced down continued flight after adding 6 qts of oil or more at the last stop.

My common findings.

Compression will be good. There's extra oil providing a better seal.

Normally a bad mag check, oil on a plug. An engine monitor will take you to the offending cylinder.

Many times pieces of the oil control ring are in the suction screen.

Normally the cylinder wall isn't damaged, I don't know how.

I find the rings broken in the box that is in a new cylinder kit.

I have also had the same problems on the Turbo Saritoga and the Machen converted Aerostar TIO540-S1AD and -U2A engines.

Want to see higher consumption? Take it up high.

Many of the people that continued flight had a dead and destroyed engine by the time they made it down from the flight levels.

The training must be good, very few off field emergency landings.

It's really bad that nothing has been done to end this problem.
 
I bet we can agree on something.

This would never have happened in an RV10:goofy:


More serious note, OLD planes with plenty of aftermarket PMA parts available can be MUCH cheaper to fix :yes:


When I heard near $4k to fix the starter adapter on a IO550....:lol:
 
kmead said:
I had two calls in the last month about sudden high oil consumption on the Lycoming TIO540 engine. So much consumption that they landed with very little oil. In both cases it was a broken oil control ring. Sudden consumption has been a bad turbo many times too, oil loss is so fast in those cases. This problem has been going on since the introduction of the new chrome edge cast iron oil control rings in 1994, So many times the people that where forced down continued flight after adding 6 qts of oil or more at the last stop.

My common findings.

Compression will be good. There's extra oil providing a better seal.

Normally a bad mag check, oil on a plug. An engine monitor will take you to the offending cylinder.

Many times pieces of the oil control ring are in the suction screen.

Normally the cylinder wall isn't damaged, I don't know how.

I find the rings broken in the box that is in a new cylinder kit.

I have also had the same problems on the Turbo Saritoga and the Machen converted Aerostar TIO540-S1AD and -U2A engines.

Want to see higher consumption? Take it up high.

Many of the people that continued flight had a dead and destroyed engine by the time they made it down from the flight levels.

The training must be good, very few off field emergency landings.

It's really bad that nothing has been done to end this problem.
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Kevin-

Please help me out here.

I have NO oil on the plugs, they are as close to perfect as a used plug gets. I have never seen a plug not show signs of oil fouling (cars/equipment) if oil is getting into the cylinder.

Borescope also doesn't show any signs of oil bypassing.

Engine monitor always has shown good as well as the mag checks (50-75 drop either mag every time).

If ring parts were loose in the cylinder, wouldn't that scar the barrel/piston? How could a piece of hardened steel pinched between the piston and barrel get into the crankcase without leaving a mark?

Given the above information, what (practically) would you do?
 
I don't know how the ring pieces can get by without damaging the cylinder.

I must be getting to old. I would pull it and check it out. I'm not talking about a couple times that this has happened to other owners.

I
 
Alex we had a Franklin engine with 4 cylinders that had broken piston rings, Didn't really scar up the cylinders much, oil consumption never got high and compressions were all good. Only way we started to find them was removing a cylinder for a heli-coil repair and the rings fell out, so we started pulling others. I have no idea what caused it or how long it had been like that.
 
kmead said:
I don't know how the ring pieces can get by without damaging the cylinder.

I must be getting to old. I would pull it and check it out. I'm not talking about a couple times that this has happened to other owners.

I
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Lacking any of the other clues you mntion, fouled plugs, bad mag check and I'm assuming clean screen and filter, to indicate a broken ring, all Alex has to go on is a couple pounds low compression in one cylinder, which seems to have come up some. Seriously, I'm not trying to be argumentative here, but if the suspect is pulled and checks ok, do you keep pulling cylinders? Sounds to me like it could be any one of them from what you describe.
 
Alexb2000 said:
Tom-

How would you know if there was a broken ring conclusively? The compression is now 74, no blow-by, borescope good, and three compression tests. These aircraft repairs are so frustrating, there seems to never be agreement on anything.
Click to expand...

When I spoke to this issue, I spoke to the sudden oil consumption change. that's a oil control ring issue, when this occurs in the cylinder and not the turbo.

the Compression wasn't a big deal to me. it could be as simple as the rings end gap aligned.
 
flyingmoose said:
Alex we had a Franklin engine with 4 cylinders that had broken piston rings, Didn't really scar up the cylinders much, oil consumption never got high and compressions were all good. Only way we started to find them was removing a cylinder for a heli-coil repair and the rings fell out, so we started pulling others. I have no idea what caused it or how long it had been like that.
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Interesting. It kept flying who knows how long. Hummm.

Chip Sylverne said:
Lacking any of the other clues you mntion, fouled plugs, bad mag check and I'm assuming clean screen and filter, to indicate a broken ring, all Alex has to go on is a couple pounds low compression in one cylinder, which seems to have come up some. Seriously, I'm not trying to be argumentative here, but if the suspect is pulled and checks ok, do you keep pulling cylinders? Sounds to me like it could be any one of them from what you describe.
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Exactly.


Tom-D said:
When I spoke to this issue, I spoke to the sudden oil consumption change. that's a oil control ring issue, when this occurs in the cylinder and not the turbo.

the Compression wasn't a big deal to me. it could be as simple as the rings end gap aligned.
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Understand not turbo, I didn't think I even mentioned the turbo.

Bottom line guys what would you do now, fly it and recheck OR tear into it OR ?
 
Fly 1 hour, check for belly stains and oil consumption. If good, fly longer and monitor.
 
Seems everyone so far is in agreement, whoop! This is also what the dealer wants to do. That's the plan then, I'm also thinking of having the oil changed and a sample sent in as well, if everything appears good on the other tests.

Quick question for A&P's, IF I pulled a cylinder could it just be put back on if all appeared well (rings free and in one piece) or does the pulling of the part necessitate inspection of the entire cylinder per the manual and the potential replacement of the cylinder just based on the tight normal wear specs?
 
bnt83 said:
I bet we can agree on something.

This would never have happened in an RV10:goofy:


More serious note, OLD planes with plenty of aftermarket PMA parts available can be MUCH cheaper to fix :yes:


When I heard near $4k to fix the starter adapter on a IO550....:lol:
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If it did, my new 260 hp IO-540-D4A5 is half the cost of a new TIO-540-AJ1A. I don't have 310 hp, can't haul what they can haul, don't have the fuel qty or go as high. I have what I could afford to build, fly and maintain. I hope to fly in a friend's 206 as soon as he gets his "oil control ring problem" taken care of...yes, another one.
 
I have a friend that has the same issue for a second time(first at 500 hrs and now at 1100+ hrs TSN) and is in the shop waiting on cylinders that are hard to come by for a 0 time reman.

FYI...He uses 100W in summer and Aeroshell 15W-50 in winter and does not run LOP. This time oil consumption went from 1 qt/7 hrs to 1 in 3 quickly. Found a small piece of oil control ring and a small piece of cam or lifter in suction screen.

Good luck with your repair.
 
Can you guys hear that sound? I think I hear scribbling pens writing an NPRM for whatever fix lycoming dreams up.


Lycoming will likely wait till the bulk of flying serial numbers are out of warranty....
 
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bnt83 said:
Can you guys hear that sound? I think I hear scribbling pens writing an NPRM for whatever fix lycoming dreams up.
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You mean running LOP? Why would they cost themselves money like that?
 
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