Glazed cylinder walls

Lance F

Lance F

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Lance F
I am inclined to believe that 2 of 4 cylinders in my Lycoming IO360A3B6D developed glazed cylinder walls after about 850 hours SMOH. The symptom is high oil consumption due to blow by. New cylinders were used in the overhaul, the plane flys about 150 hours per year and always used Phillips XC.

Glazed cylinder walls are normally a problem with break in. My question is how could this happen spontaneously on a mid time engine? There was no known change in how the engine was operated.

I may or may not pull these cylinders, but I'd sure like to know what happened.

Ideas?
 
Lance F said:
I am inclined to believe that 2 of 4 cylinders in my Lycoming IO360A3B6D developed glazed cylinder walls after about 850 hours SMOH. The symptom is high oil consumption due to blow by. New cylinders were used in the overhaul, the plane flys about 150 hours per year and always used Phillips XC.

Glazed cylinder walls are normally a problem with break in. My question is how could this happen spontaneously on a mid time engine? There was no known change in how the engine was operated.

I may or may not pull these cylinders, but I'd sure like to know what happened.

Ideas?
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Until you have them on the bench, and do a complete inspection, you won't know.

800 hours? after market cylinders?
 
Any oil leaks coming from pull rod seals or anywhere else etc? they can gush
 
timwinters said:
Couldn't one tell nearly just as much, far cheaper, w/ a borescope?

Don't know...just askin'
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The borecscope will not see the condition of the rings. nor will it see the condition of the valve guide, or measure the bore for proper size.
 
I'd ask if they were factory or aftermarket cylinders and rings. It could be the rings just wore out. If they're aftermarket, this wouldn't surprise me. The factory Lycoming cylinders seem to do a much better job on their engines. Continentals, it's variable.
 
Skylane81E said:
If it's just rings at least the solution isnt too bad.
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Maybe….. if he stuck a ring in the piston, it could get really bad..


that is why we need to pull them off and have a look.
 
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If the cylinders are glazed the only thing that might have caused this is overheating. That's what causes it during breakin. It also could be loss of ring tension due to overheating. BTW there are no aftermarket clinders for this engine. Charlie Melot Zephyr Engines
 
Charlie is right. There are no aftermarket cylinders for the angle valve cylinders. These were factory new.
We've looked in the cylinders with a boroscope. They all look fine.
Overheating is very doubtful. I have a JPI engine monitor and download and review the data. I doubt that these cylinders have ever seen 400 deg. 380 is more likely the max.
There's got to be a cause, but if a removal and inspection doesn't find any ring issues, I am afraid the root cause will remain unknown. And I don't like that.
 
Have you thought installing an oil separator like the M20. I have one on my M20J and have no oil stains even at 8 quarts. At 8 quarts oil burn is 8hrs/qt. I assume your compression is good. I use aeroshell 15W-50.

José
 
Piloto said:
Have you thought installing an oil separator like the M20. I have one on my M20J and have no oil stains even at 8 quarts. At 8 quarts oil burn is 8hrs/qt. I assume your compression is good. I use aeroshell 15W-50.

José
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many would argue that this is a bandaid
 
Lance F said:
Charlie is right. There are no aftermarket cylinders for the angle valve cylinders. These were factory new.
We've looked in the cylinders with a boroscope. They all look fine.
Overheating is very doubtful. I have a JPI engine monitor and download and review the data. I doubt that these cylinders have ever seen 400 deg. 380 is more likely the max.
There's got to be a cause, but if a removal and inspection doesn't find any ring issues, I am afraid the root cause will remain unknown. And I don't like that.
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Before you remove them, do the valve wobble check.
 
By fine I mean no scratches, gouges or obvious abnormalities. You can see the cross hatch, but frankly what does glaze look like? The glaze diagnosis came from two reputable cylinder rebuilders, including Charlie's cylinder overhaul guy. BTW compressions are 72 and 73 on the suspect cylinders.
 
Lance, I don't think you're glazed. I think you have bad rings.

Doesn't really matter. You gotta pull 'em and look at it. Glazing usually is saved for turbocharged engines run hot. And TSIO360EBs will run right up there if I let 'em....and I haven't glazed one yet, >2,000 hours. of operations, 65% by the book.

Your operations are quite conservative with good margins - (I've seen 'em).

Betcha have a ring problem.
 
If your two opinions were suggested without seeing what you saw through the bore scope, then it seems your inspection debunked their theory and Doc has a better diagnosis. If they did, I'd be curious too.

You might ask on the Yahoo Lycoming Groups forum, some good engine advice there.

Glazing looks like glazing.....the cross hatch clearly won't be the surface your rings are running on.
 
It just ticks me off that I gotta pull cylinders with 72+ compression at less than TBO. I've got missions to fly.
 
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Which nos are they- at least in the same bank (less hours spent battling baffling?)....
 
Lance F said:
It just ticks me off that I gotta pull cylinders with 72+ compression at less than TBO. I've got missions to fly.
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How did you identified the bad cylinders?. How much oil are you loosing? Loosing just a quart by blow-by would make a real mess on the belly. Have you check the bottom plugs for oil? What is the color of the exhaust stain? If the color is black you maybe burning oil instead of dumping it by blow-by. Is the crankcase vent line kinked or has any holes on it?. This would cause case pressure build up that will force oil into the combustion chamber during the intake cycle. Make sure the line is venting toward the back with no holes along the line.

José
 
I'd bet that you have a ring problem, also. Which, I agree, is very annoying, especially with good operating practices. If you were approaching TBO, I'd say the air/oil separator just to get a few more hundred hours out of it might not be such a bad idea. Bandaid, yes, but one needs to weigh cost vs. benefit. Given that you're not even halfway to TBO, it likely makes sense to just order 4 sets of rings, pull the cylinders, and do a ring job. If the shop is properly equipped, they should be able to do this pretty quickly.

Before you pull the trigger, though, it might also be worth a call to Lycoming tech support. Mike Damiani usually has some good ideas there (seems he's usually the one who answers). Tell him or Dennis I said hi.
 
Lance F said:
By fine I mean no scratches, gouges or obvious abnormalities. You can see the cross hatch, but frankly what does glaze look like? The glaze diagnosis came from two reputable cylinder rebuilders, including Charlie's cylinder overhaul guy. BTW compressions are 72 and 73 on the suspect cylinders.
Click to expand...

Remember oil consumption has nothing to do with compression. The top rings are for compression the lower ring is the oil control ring.

The top rings can be in great condition from being over oiled by a faulty oil control ring, and the cylinder will be in very good condition too, but you will have high oil consumption and oil that turns black quickly.
 
Tom hit the nail on the head there.
 
Yep, oil in the cylinder can even make the compression numbers better as the oil acts as a seal in the cylinder. I topped a TIO-540-J2BD a few years ago due to high blow by and oil consumption. Compressions were all in the high 70s but not one cylinder didn't have a mix of broken and stuck compression rings.
 
How many folks know what a glazed cylinder really is?
 
Its a little simple and unless I missed it doesn't mention glazing.

Granted you are most likely to coke oil on your cylinder walls durring break in.
 
It does mention glazing at the very end.

Their logic (high temps with low cylinder pressures) seems plausible to me.
 
Ah, guess I did miss it. Like I said slightly simple but that's not bad for the operator.
 
How about these two paragraphs :

A straight weight non-dispersant mineral oil conforming to SAE J1966 is recommended for the break-in period. If you fly less than once per week, a straight mineral oil with corrosion preventative (MIL-C-6529 Type II) should be used for the first oil change period (25 hours). The proper viscosity of the oil should be selected based on ambient operating air temperature. Refer to the Operation & Installation manual specific to your engine or the Airplane Flight Manual / Pilot Operating Handbook for the viscosity and grade of oil required. Refer to the most current version Service Bulletin SIL99-2 for approved lubricants.
Piston ring seating is paramount to proper engine break-in. Your understanding of the factors involved in the break-in process will aid in correctly operating the engine during this important time. Piston ring seating means the rings and the cylinder wall must wear-in together to provide an effective seal for the combustion chamber and to keep combustion gas blow-by and oil consumption to a minimum.
 
Skylane81E said:
Lyc says AD oil for T engines
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If you have a filter on the engine, why would you want a non"D" oil during break in? wouldn't you rather have the break in debris carried to the filter by the "D"oil ? or is it better to have it fall out of suspension in the sump?

Read oil talk for dummies at ECI2FLY.com ECI advises 20W50 from day one to TBO, and it works.
http://www.eci.aero/pdf/BreakInInstructions.pdf
 
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Lance, do you know the history of compressions and oil usage on your engine for the 850 hours? You reported high oil usage due to blow by. How much oil usage and has it changed a lot? Were compressions steady for 850 hours?

I have a hard time understanding much for blow by with compressions all above 72. I had cylinder number 3 on a Victor chrome jug OH'd 180 Lycoming test 65-72 for 400 hours and the leakage could always be heard comming from the oil fill tube. The plugs always were clean until the last annual inspection when number 3 tested 50 and the lower plug was oil fouled. The jug was removed and showed scoring and the rings were pitted. It was sent in for repair and reinstalled with new cast iron rings. I am still breaking in that jug going low and fast but it takes alot of 100LL.:yikes: I had extreme oil fouling problems at first with it until I put fine wire plugs in and have not fouled a plug since. I am a firm believer in fine wires for break-in. How are you supposed to run it hard with high jug pressures if the plugs are not firing? Please let us know what you find?

Rick
 
Tom-D said:
If you have a filter on the engine, why would you want a non"D" oil during break in? wouldn't you rather have the break in debris carried to the filter by the "D"oil ? or is it better to have it fall out of suspension in the sump?

Read oil talk for dummies at ECI2FLY.com ECI advises 20W50 from day one to TBO, and it works.
http://www.eci.aero/pdf/BreakInInstructions.pdf
Click to expand...


Isn't the oil dispersant in reference to organic deposits and maintaining soot, carbon, "sludge" in suspension, rather than metallic? I would think regardless of the oil type, break-in debris would be carried to the filter (due to oil velocities maintaining suspension), with some precipitation in the sump.

The argument I've always heard for "break-in" oils (either Non"D", straight mineral, etc.) is that the less slippery, the better. You want the high peaks on the surface finish to wear, rather than just slide by. But Ive never seen evidence showing that the dispersant package is slippery. Maybe by focusing on a straight mineral, they eliminate the chance of it having any friction modifiers in the additive package.


Edit://
Found a article that explains ashless dispersant mineral oil.
http://www.aviationtoday.com/am/repairstations/The-Mineral-Oil-Myth_564.html
 
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TripleZ said:
Isn't the oil dispersant in reference to organic deposits and maintaining soot, carbon, "sludge" in suspension, rather than metallic? I would think regardless of the oil type, break-in debris would be carried to the filter (due to oil velocities maintaining suspension), with some precipitation in the sump.

The argument I've always heard for "break-in" oils (either Non"D", straight mineral, etc.) is that the less slippery, the better. You want the high peaks on the surface finish to wear, rather than just slide by. But Ive never seen evidence showing that the dispersant package is slippery. Maybe by focusing on a straight mineral, they eliminate the chance of it having any friction modifiers in the additive package.


Edit://
Found a article that explains ashless dispersant mineral oil.
http://www.aviationtoday.com/am/repairstations/The-Mineral-Oil-Myth_564.html
Click to expand...

Do you understand what an EP oil is ?

Remember the oils we use are all from the same base stock, and all have the same lubrication properties except the EP oils which are fortified to a higher film strength than the regular AD oils by the additive package.
 
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