My 0-540 dropped a cylinder... UGH

k9medic

k9medic

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ATP-H, CMEL, CSEL, CFI/CFII Airplanes and Helicopters
We were in the process of finishing up the annual on our PA32-260 and everything was going well. Too well it seemed...

The last thing we were were going to do before closing everything up and signing off the annual was to do the compression test. Just our luck, one of the cylinders came back at 40psi!

I understand this is a static test but for the life of me, there was no change in performance that I could perceive. We flew the aircraft just under 100 hours this past year. Average flight was 3 hours at a time. Climb, level off and cruise. Plugs were surprising foot balled compared to last year.

Now to tear off the cylinder and send it out. Oh well, it's only money right?
 
This was a cold compression test?

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Have you determined where it is leaking? Borescope the cylinder?

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mwagg737 said:
This was a cold compression test?

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Unless there was a previously suspected issue with the engine, than performing the compression test cold is pretty standard.

I’d be curious to know where it’s leaking from.
 
A cylinder can be really really low and not affect its performance. Where was the air leaking from...exhaust, dip stick, air box? Did you borescope it to look at cylinder walls and valves?

I would not go pulling this cyclinder yet if it were me. I'd want some more investigation first.
 
You have to be near zero compression to really notice. I would have done more research my self. Brought several low cylinders back to life before. Granted for what mechanics have to charge for labor these days it doesn’t take much digging to pay for a cylinder overhaul.
 
mwagg737 said:
Have you determined where it is leaking? Borescope the cylinder?
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borescope isn't going to stop the leak. we should already know where it is leaking from.
 
Grum.Man said:
You have to be near zero compression to really notice. I would have done more research my self. Brought several low cylinders back to life before. Granted for what mechanics have to charge for labor these days it doesn’t take much digging to pay for a cylinder overhaul.
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Low compression is a symptom, it will not repair itself.
 
Tom-D said:
borescope isn't going to stop the leak. we should already know where it is leaking from.
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Right. But if it's a simple case of lapping the valve, then it may not be worth the money to replace the cylinder.

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Yes. Foot balling a plug is normal wear on a plug. What surprised me was how rapid the where was over the past 100 hours in comparison to the last time we checked the plugs.

The IA checked for air in the exhaust and out the oil filler.

Prior to us buying the airplane is maybe flew 3-4 hours a year.

I routinely fly this plane at max gross weight to and from the islands. No sense nickel and diming things.

Just hate it though.


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From the looks of that plug you run rich. Could just be crap stuck in the lands. Try a ring wash. Can't hurt, might help, don't cost nuthin'
 
k9medic said:
The last thing we were were going to do before closing everything up and signing off the annual was to do the compression test. Just our luck, one of the cylinders came back at 40psi!
Click to expand...
As @Let'sgoflying! said compression is the first thing I do. I have a spare cylinder on the shelf if needed....:rolleyes:
 
Chip Sylverne said:
From the looks of that plug you run rich. Could just be crap stuck in the lands. Try a ring wash. Can't hurt, might help, don't cost nuthin'
Click to expand...

Those are not my plugs - somebody posted an example of a footballed plug. I know for a fact that prior to our purchase the aircraft was not operated in the most efficient manner. My plugs looked great except for the footballing. Only about 250 hours on the plugs.

This engine was installed on 10/2004.
 
AKBill said:
As @Let'sgoflying! said compression is the first thing I do. I have a spare cylinder on the shelf if needed....:rolleyes:
Click to expand...

That's a good idea....
I just had a bad intake valve on my IO-540. We checked compression first and found it. The valve seat was bad....
Would have been a lot less stressful if I'd had a spare....

So if a new cylinder is installed what should be done to break it in properly ?
Should new rings be used?
 
Hunt-man said:
So if a new cylinder is installed what should be done to break it in properly ?
Should new rings be used?
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A new or overhauled cylinder assembly will come with new rings installed on piston. Follow engine manufactures procedures for break in. I use a mixture of STP and engine oil for installing the piston into the cylinder then a mineral oil for the first 25 to 50 hours of break in. The first few hours I try to run a minimum of a 1 hour flight at 2500rpm.
 
k9medic said:
We were in the process of finishing up the annual on our PA32-260 and everything was going well. Too well it seemed...

The last thing we were were going to do before closing everything up and signing off the annual was to do the compression test. Just our luck, one of the cylinders came back at 40psi!

I understand this is a static test but for the life of me, there was no change in performance that I could perceive. We flew the aircraft just under 100 hours this past year. Average flight was 3 hours at a time. Climb, level off and cruise. Plugs were surprising foot balled compared to last year.

Now to tear off the cylinder and send it out. Oh well, it's only money right?
Click to expand...
Hopefully you will run a warm-engine dynamic compression check before yanking the jug. The static test (I have a nice Snap-On leakdown tester from 40 years ago) should let you know where the leakage is from, which I don't see here.
Also, if you change the cylinder, the rings get changed; our guy would only let you put used rings back in the same cylinder they came from, and then only if the time was low.
 
It's like this for me.
I know annual time is coming so I try to plan it to start right after the last flight in that month.
Bathe it (that is part of every annual btw), complete that flight, get into the hangar.
Go for the thing that needs 'hot' first (oil drop if needed, compression test)
And start checking the potentially expensive, or 'delaying' stuff first as well.
 
btw.....a "football" just doesn't happen in a few hours. It takes hundreds and hundreds of hours.....to wear a football. ;)
 
Well my IA pulled the cylinder today. Walls had some scratches. No cross hatching. Top of piston didn't look too bad. Sides had some decent pitting on them though and you could see where it was making contact with the cylinder wall. 4 broken exhaust studs to add to the repair.

While checking the motor mounts, realized that all of the mounts were the same part number. -35's. They should be a -35 and a -38 for each mount. Perhaps that is why this plane has always had a trim issue. Now it's time buy new mounts as well.

I just can't believe a new engine was hung with the wrong mounts!
 
k9medic said:
I just can't believe a new engine was hung with the wrong mounts!
Click to expand...

I recently had an overhaul and my mechanic discovered my bottom two mounts were installed backwards, which, looking at the logs, appears to have occurred when the engine was installed new 26 years ago...
 
Probably want be the last “issues” you find. Lots of shade tree mechanics with a fancy piece of paper. Even more concerning is the number of shops using non A&P mechanics and the shop owner signing off their work.
 
Grum.Man said:
Probably want be the last “issues” you find. Lots of shade tree mechanics with a fancy piece of paper. Even more concerning is the number of shops using non A&P mechanics and the shop owner signing off their work.
Click to expand...

...which is perfectly legal IF the shop owner or the resident A&P-IA has supervised appropriately. -Skip
 
Skip Miller said:
...which is perfectly legal IF the shop owner or the resident A&P-IA has supervised appropriately. -Skip
Click to expand...

Didn't say it wasn't. It is a poor practice though as there is no way the shop owner or lead A&P assuming they are even competent in the first place could properly oversee a shop full or mechanics. I have seen several examples of this and have known a few of these shop owners to have their license suspended, forced to retest, and work on probation for a period of time.
 
We did...

Had other stuff to accomplish during this annual and just got around to the compression check at the end.


On another note, did some extensive research and contacted Lord directly. It turns out that the amounts that we have are the correct ones. It happens to be the one off for my serial number.


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Well we got the cylinder back - $675 from zephyr engines.

Got everything out back on and now waiting to some free time to do a leak check.

Ordered 12 new plugs as well.


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Grum.Man said:
Didn't say it wasn't. It is a poor practice though as there is no way the shop owner or lead A&P assuming they are even competent in the first place could properly oversee a shop full or mechanics.
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Really, I'd say that's not that cut and dry. I was talking to a non-A&P today that really knows his stuff, probably better than a few A&Ps that work on my plane. Let the IA or lead A&P make that determination. It's their reputation, not yours.
 
k9medic said:
Well we got the cylinder back - $675 from zephyr engines.

Got everything out back on and now waiting to some free time to do a leak check.

Ordered 12 new plugs as well.


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Click to expand...

So what problem did they find in the cylinder?

My engine shop was $875 for a bad valve seat and valve. First annual for this plane and it ate my wallet.. I did add a Surefly mag and a new ELT. And had my right slick mag serviced. IO-540
 
k9medic said:
I understand this is a static test but for the life of me, there was no change in performance that I could perceive.
Click to expand...

FYI, cylinders with low compression do not normally result in any significant loss of power. However, the low compression numbers indicate that there is a leak somewhere, typically past the piston rings (which would normally be accompanied with increased oil consumption) or maybe the exhuast valve (which would be of greater concern because of impending valve failure, which would almost certainly ruin your flying day.) Addressing the issue properly is the wise course of action. And as you say, it's only money. Fly safe.
 
Grum.Man said:
Probably want be the last “issues” you find. Lots of shade tree mechanics with a fancy piece of paper. Even more concerning is the number of shops using non A&P mechanics and the shop owner signing off their work.
Click to expand...

And hence those $400 annuals you hear about!
 
The 8130 says the following:
repaired cylinder. installed the following new parts: SL74230 OS EX guide. SL19001 EX Valve. SL11800 springs. SL11795 Springs. AEL31C-13 P3 studs. AEL66610 bushings. MS13997-3 keys. SL3601 SC Ring set.

so if I am reading it correctly, exhaust guides and valves. New springs, keys and rings.
 
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