Trashed IO-540 jug

RotaryWingBob

RotaryWingBob

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iHover
After I touched down tuesday, the pilot/A&P in the next hangar came running out. When I had completed the shutdown sequence he told me he could see oil dripping out and that there was some smoke. When he removed the cowling and valve covers yesterday, it was an "oh sh*t", better get the dealer's mechanic down here. One of the guys flew him down this morning and the attached pictures showed what we found.

The theory is that the cap you can see sitting there broke loose and got jiggled onto the oil drain hole. The resulting oil pressure under the valve cover caused the valve to open and get impacted by the piston. The push rod, not surprisingly, is bent.

The engine has 241 TT on it! Hopefully Lycoming will replace the jug...
 

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thats sucky, guess you'll just have to fly the -22 for a while
 
smigaldi said:
That is a big PIA! But at least it happened close to ground and nothing else other than the push rod got bent.
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We think it failed in flight, Scott. The oil was down about 1/2 qt when I departed for the trip home. It was down 2 qts after shutdown (45 minute flight). There were no indications of trouble -- no warning lights and CHT, oil pressure and temperature were all normal. It's possible that the power reduction was masked by the governor cranking in more power.
 
dang bob, im sorry!

gliders down for a fabric tear right now, but i plan to fix that tomorrow night. i like it that most of the stuff that can break on the glider is easy to fix.
 
All this almost has me reconsidering buying an airplane. Almost.

Did I mention that the one we've been looking at has been grounded because they've found metal in the last few oil analysis reports?
 
gprellwitz said:
All this almost has me reconsidering buying an airplane. Almost.

Did I mention that the one we've been looking at has been grounded because they've found metal in the last few oil analysis reports?
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Yeah, making metal is a bummer...

I used to hear this quiet whisper, so quiet that I wasn't sure I really heard it. Now it's ramped up to a shout.

It keeps saying "Turbine. Turbine. Turbine. Turbine. Turbine. Think turbine, dammit!" :D
 
sounds like a stuck valve to me....

that plug looks like it couldn't possibly seal against that oil drain hole.
 
Checkout_my_Six said:
sounds like a stuck valve to me....

that plug looks like it couldn't possibly seal against that oil drain hole.
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+1 on that theory.
Sounds like the infamous "rope trick" needs to be performed on this engine. Remove the valve, ream the guide and reinstall. It can all be done without removing the jug.
 
RotaryWingBob said:
I used to hear this quiet whisper, so quiet that I wasn't sure I really heard it. Now it's ramped up to a shout.

It keeps saying "Turbine. Turbine. Turbine. Turbine. Turbine. Think turbine, dammit!" :D
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Price out an overhaul first. And a hot section inspection. Jugs suddenly look very, very cheap.
 
NC Pilot said:
+1 on that theory.
Sounds like the infamous "rope trick" needs to be performed on this engine. Remove the valve, ream the guide and reinstall. It can all be done without removing the jug.
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I don't buy that, Mark. One look at the pushrod makes me think there's more damage. And this engine is still under warranty.
 
RotaryWingBob said:
I don't buy that, Mark. One look at the pushrod makes me think there's more damage. And this engine is still under warranty.
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OK, but this is not unusual for Lycoming engines. Particularly ones with higher HP output.
 
A few years ago, I lost my 3rd exhaust valve out the exhaust. Go figure
 
The cylinder is unlikely to be damaged. It will need the guide reamed. Have the pushrod socket and tappet bore inspected. One in a while the socket gets cocked and breaks the tappet necessitating a teardown to replace it. As others have stated it is an unusual occurrance in the "angle valve" 200 & 300 HP engines. Let us sknow how it comes out and what Lycoming had to say. Charlie Melot Zephyr Aircraft Engines
 
RotaryWingBob said:
After I touched down tuesday, the pilot/A&P in the next hangar came running out. When I had completed the shutdown sequence he told me he could see oil dripping out and that there was some smoke. When he removed the cowling and valve covers yesterday, it was an "oh sh*t", better get the dealer's mechanic down here. One of the guys flew him down this morning and the attached pictures showed what we found.

The theory is that the cap you can see sitting there broke loose and got jiggled onto the oil drain hole. The resulting oil pressure under the valve cover caused the valve to open and get impacted by the piston. The push rod, not surprisingly, is bent.

The engine has 241 TT on it! Hopefully Lycoming will replace the jug...
Click to expand...

The only way that that cap can come out is by the valve sticking open, and then it had to stick shut for the pushrod to bend. My question is why did this happen on a 241 hr engine? I hate to say it, but at this point I wouldn't trust ANY of the jugs or the engine in general until I found out WHY this happenned.
 
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NC Pilot said:
+1 on that theory.
Sounds like the infamous "rope trick" needs to be performed on this engine. Remove the valve, ream the guide and reinstall. It can all be done without removing the jug.
Click to expand...

Not a chance in hell I'd trust that in this situation. That valve was tagged by a piston, I'd bet my bottom dollar it's bent, and I'd also risk a parly on a ding in the piston top. This is an engine under a double warantee situation, get it done right.
 
Henning said:
Not a chance in hell I'd trust that in this situation. That valve was tagged by a piston, I'd bet my bottom dollar it's bent, and I'd also risk a parly on a ding in the piston top. This is an engine under a double warantee situation, get it done right.
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I was referring to the procedure to prevent this situation, not what to do with this particular cylider, which needs to be removed, inspected and repaired.
 
Henning said:
The only way that that cap can come out is by the valve sticking open, and then it had to stick shut for the pushrod to bend. My question is why did this happen on a 241 hr engine? I hate to say it, but at this point I wouldn't trust ANY of the jugs or the engine in general until I found out WHY this happenned.
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You are dead right! We're having a strategy meeting tomorrow and will be putting the screws to both Robinson and Lycoming for a new engine.

It's starting to look like the cap has been loose for quite a while -- you can see where it wore the metal down on the right side. It may have been a manufacturing/assembly FU.
 
I'm trying again. It seems to take a couple of posts before anything appears. If this information shows in another post that's why. Henning's point is good that the valve may have hit the piston. A borescope would tell in a minute. As for stresses on the rocker arm or rocker boss they are quite substantial and not prone to breaking. The pushrod on the other hand is not and bends easily. Again sticking "angle valves"are rare. I can't count a half dozen in 36 years in the engine business. Parallel valves are another story. I've seen somewhere in the low hundreds. Charlie Melot
 
charlie said:
I'm trying again. It seems to take a couple of posts before anything appears. If this information shows in another post that's why. Henning's point is good that the valve may have hit the piston. A borescope would tell in a minute. As for stresses on the rocker arm or rocker boss they are quite substantial and not prone to breaking. The pushrod on the other hand is not and bends easily. Again sticking "angle valves"are rare. I can't count a half dozen in 36 years in the engine business. Parallel valves are another story. I've seen somewhere in the low hundreds. Charlie Melot
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Can you describe what the difference is between a parallel valve and a angle valve are for us mechanically challenged pilots? Once you do that, if you would be so kind can you also tell us why one is more prone to sticking?
 
smigaldi said:
Can you describe what the difference is between a parallel valve and a angle valve are for us mechanically challenged pilots? Once you do that, if you would be so kind can you also tell us why one is more prone to sticking?
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In parallel valve Lycoming engines the valve stems are parallel to one another and perpendicular to the top of the piston. The valves in an angle valve engine the valve stems are at an angle to one another and therefore not perpendicular to the piston. Parallel valve engines are the O-235 series, and the 125,135,150,160,170,180,235,250,260, and 270 HP carbureted and fuel injected engines. Angle valve engines are the 200,300 and the turbocharged engines of 300 HP and up. The Robinson engine that started this thread is an exception being a 300 HP engine derated to 250. Charlie Melot
 
smigaldi said:
Can you describe what the difference is between a parallel valve and a angle valve are for us mechanically challenged pilots? Once you do that, if you would be so kind can you also tell us why one is more prone to sticking?
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Some interesting reading regarding parallel valve Lycoming engines and valve wear issues.
http://egaa.home.mindspring.com/engine1.htm
 
Steve said:
Bear in mind that information is nearly 10 years old and if the engine on the Robinson is newer than 10 years old it may not directly apply.

http://egaa.home.mindspring.com/new.htm
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The engine on the Robinson is also an angle valve engine, so this does not apply. I was trying to give Scott some information on parallel valve engines. I believe he has one of those in his plane (IIRC a carburated O-540).:D
 
NC Pilot said:
The engine on the Robinson is also an angle valve engine, so this does not apply. I was trying to give Scott some information on parallel valve engines. I believe he has one of those in his plane (IIRC a carburated O-540).:D
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O-540 in a Warrior? That'd be zippy! :goofy:
 
smigaldi said:
Bob any update??
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Nothing substantial. The oil leak is unrelated to the cylinder problem. During the annual the dealer's A&P/IA retorqued the valve cover. The trouble is that it had a silicon gasket which is not supposed to be retorqued. That caused the oil leak. Which was a good thing in a way since it made us remove the valve cover which allowed our A&P to discover that there was a more serious problem.

Since we don't know the extent of the damage, we are still trying to get Robinson or Lycoming to cough up a new engine.
 
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