Cylinders and overhaul question

Bill

Bill

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Say at TBO someone did an overhaul, used new pistons, rings, etc., but had the cylinders overhauled instead of using new. Re-honed, dressed the valve seats, new valve guides, etc.

Would such cylinders be expected to go 2000 to the next TBO, or would they die early, and if so, how early?

Engine in question is IO-360 4 Lyco
 
My policy has always been to install new cylinders when doing an overhaul. Not to say that refurbished cyinders cannot last until TBO, but I believe the chances are not as good as going with new.

Are there records of the as found and as left conditions of the cylinder (bore size, taper, amount of valve grinding needed, etc.)? I believe the IO-360 pushes the limits of the Lycoming engine a little and this engine is definately stressed more than the 180 HP versions.

Should be worth a slight reduction in price IMHO.
 
Is this the first time each sylinder has been overhauled?

I have had several engine shops tell me that a first-run cylinder, being overhauled the first time is generally fine (and in the opinion of some, preferable). After the first time, they generally recommended new cylinders.

There was some qualification of that advice depending on cylinder and engine (think turbocharged), but the opinion I took away was that a good, operating cylinder that is overhauled properly should make a second run.
 
The life expectancy of an overhauled cylinder is entirely depandant upon the history of the cylinder and the reputation of the overhaul shop.
 
NC19143 said:
The life expectancy of an overhauled cylinder is entirely depandant upon the history of the cylinder and the reputation of the overhaul shop.
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Tom,

Cylinders were new Lycoming installed in 1992, and supposedly ran to TBO without problems. The overhaul was done by Engine Components, Inc., of San Antonio, TX., know anything about them?

Correcton: The cylinders were overhauled by Aircraft Engine Works of Jacksonville, FL, the crank, rockers, con rods, and fuel distributor overhauled by ECI, engine gears overhauled by G&N, mags overhauled by Kelly Aerospace.

Thanks!
 
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Bill,

We bought our Bonanza with 400 hours on it. At 700 hours the cylinders were shot. We had them overhauled. Now, at 2,000 hours, the compression is still excellent and we add one quart of oil every 30 hours between changes.

I think there's much more to be said for how the airplane is flown than for the difference between new and overhauled cylinders - providing the overhaul is done well.

I, personally, wouldn't let the overhauled cylinders put me off if everything else looked good. Until you guys are the ones flying the airplane you just can't know how the engine was treated. You pays your money, you takes your chances.
 
gibbons said:
I, personally, wouldn't let the overhauled cylinders put me off if everything else looked good. Until you guys are the ones flying the airplane you just can't know how the engine was treated. You pays your money, you takes your chances.
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Engine presently has 12 hrs on it since overhaul, so other than breakin, how it is flown would be up to us.
 
Bill Jennings said:
Tom,

Cylinders were new Lycoming installed in 1992, and supposedly ran to TBO without problems. The overhaul was done by Engine Components, Inc., of San Antonio, TX., know anything about them?

Correcton: The cylinders were overhauled by Aircraft Engine Works of Jacksonville, FL, the crank, rockers, con rods, and fuel distributor overhauled by ECI, engine gears overhauled by G&N, mags overhauled by Kelly Aerospace.

Thanks!
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Do you know this info first hand, and know it is correct? We have trouble tracking cylinders because we are not required to use S/Ns when we make the log entry.

But if the cylinders were in fact first run, they should have no problem going to TBO the second time if reworked by a good shop.

If it were my engine I would insist that they be reground .010" over and refitted with new pistons and rings, new guides, and NEW valve seats, and new springs & keepers. with rotators if used.
 
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NC19143 said:
Do you know this info first hand, and know it is correct?
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The overhaul shop (Aircraft Engine Works) noted all of the vendors in the logs, and all of the receipts from the vendor shops are stapled into the engine log.
 
Bill Jennings said:
The overhaul shop (Aircraft Engine Works) noted all of the vendors in the logs, and all of the receipts from the vendor shops are stapled into the engine log.
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What does the work order from the cylinder shop say.?
 
Generally speaking, the expected life of a cylinder goes down each time it's overhauled. If you are dealing with cylinders that were installed new, run to TBO, and then overhauled, and the engine was neither abused nor neglected, you've got a real good chance of not having any cracks or other serious problems out to recommended TBO. If they're second-overhaul cylinders, the odds start dropping fast. The problem is that there are no tags or other records that go with cylinders to show how many times they've been overhauled, so unless they've stayed since they were new on the engine on which they are currently installed (in which case their life history is in that engine's maintenance records), you have no idea how many times they've been overhauled, and that ain't a recipe for good odds on lasting to recommended TBO.
 
Sigh..........................


Sometimes brand new engines with brand new cylinders fail.

You haven't lived till you flown a few hours behind a big round engine that there is no way of knowing how old the cylinders are or how many times they have been overhauled.:hairraise:
 
Ron Levy said:
Generally speaking, the expected life of a cylinder goes down each time it's overhauled. If you are dealing with cylinders that were installed new, run to TBO, and then overhauled, and the engine was neither abused nor neglected, you've got a real good chance of not having any cracks or other serious problems out to recommended TBO. If they're second-overhaul cylinders, the odds start dropping fast. The problem is that there are no tags or other records that go with cylinders to show how many times they've been overhauled, so unless they've stayed since they were new on the engine on which they are currently installed (in which case their life history is in that engine's maintenance records), you have no idea how many times they've been overhauled, and that ain't a recipe for good odds on lasting to recommended TBO.
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I believe you carry the problems of Cont. and Franklin over to Lycoming, Lycoming doesn't have the warpage and cracking problems caused by age that Continental and Franklin do, the aluminum alloy is different and the design does not lend its self to aging problems. When the overhaul is completed IAW the Factory methods we often see 4-5 overhauls on Lycoming cylinders and they go to TBO each time.

The limiting factor in how many times a lycoming cylinder can be overhauled is determined by how many times it can be bored over size. You must stay with in the size of the replacement parts such as .005", .010", .015", etc. over on the pistons and ring sets. Once you have bored beyond the nitrided thickness of the cylinder wall the cylinder must then be chrome plated back to standard, and then we can start over with piston and ring sets at standard.

The soft point in a Lycoming cylinder is the exhust port, the exhaust studs are a plane steel and corrode to a point they will not hold the exhaust system on the cylinder, they can be drilled out and replaced but the port its self errodes to a point the stud has no wall thickness to be mounted in, this can have a weld repair by adding wall thickness and remachining.

But at what cost do you place on the repair of a cylinder vs a new one, Lycoming cylinders are expensive, that is why we have so many things we repair on them before we throw them away.
 
Tim said:
Sigh..........................


Sometimes brand new engines with brand new cylinders fail.

You haven't lived till you flown a few hours behind a big round engine that there is no way of knowing how old the cylinders are or how many times they have been overhauled.:hairraise:
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Ya Know its a funny thing Tim, the old radials don't have cylinder problems, unless some ham fisted pilot abuses them. but on the other hand the flat engines with all the engine monitors do,,,,, What's up with that?
 
NC19143 said:
What does the work order from the cylinder shop say.?
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I spoke with the mechanic at the shop, and he looked it up and said the cylinders were 1st run Lycoming factory cylinders. They honed, replaced the exhaust valve, guide, and re-ground all valve seats and faces. The intake valves were re-used as they looked good, with new guides.
 
Bill Jennings said:
I spoke with the mechanic at the shop, and he looked it up and said the cylinders were 1st run Lycoming factory cylinders. They honed, replaced the exhaust valve, guide, and re-ground all valve seats and faces. The intake valves were re-used as they looked good, with new guides.
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That's very typical of the work being completed on first run cylinders. I'd have no problems with that.
 
Bill Jennings said:
I spoke with the mechanic at the shop, and he looked it up and said the cylinders were 1st run Lycoming factory cylinders. They honed, replaced the exhaust valve, guide, and re-ground all valve seats and faces. The intake valves were re-used as they looked good, with new guides.
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As long as they used the good high-chrome valve guides (not sure you can even get the old ones anymore), that sounds solid.
 
Bill Jennings said:
I spoke with the mechanic at the shop, and he looked it up and said the cylinders were 1st run Lycoming factory cylinders. They honed, replaced the exhaust valve, guide, and re-ground all valve seats and faces. The intake valves were re-used as they looked good, with new guides.
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And hopefully they paid close attention to the valve-seat interface. As I understand it, this is critical for heat transfer and hence valve life. IOW you need more than just a good seal when the valve is closed.
 
lancefisher said:
And hopefully they paid close attention to the valve-seat interface. As I understand it, this is critical for heat transfer and hence valve life. IOW you need more than just a good seal when the valve is closed.
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He'll know how well they did in about 300 hours.
 
My O-360 was rebuilt using the original first run cylinders. At 800 SMOH all four cylinders had cracked exhaust ports and had to be replaced again. This time I went with new Lycoming cylinders. At 2000 hours, 1200 on these cylinders , I plan to get them rebuilt but I wouldn't rebuild 2000 hour cylinders. The cost to rebuild a cylinder "right" is almost the same as new cylinders . . . . why chance it?
 
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