In-Flight Loss of No. 3 Cylinder; Need overhaul recs

flyingron said:
I still have a cylinder and piston on my desk here from when my Gopher35 did the same thing. Not only did it beat the hell out of the cylinder and bent the piston such that the ring lands have a nice dip in them it went all the way through the piston and beat up the c-rod as well. By the time I finished having the engine torn down, we pretty much declared it a total loss.
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I also have a badly beat up piston and cylinder, from a motorcycle. The piston was bent like you describe, with the ring groove deformed and the cylinder was trashed. The connecting rod and bottom end looked fine when I pulled the cylinder, so I just replaced them and the bike ran fine for several years after that.

You should definitely look for any signs that the failed cylinder has caused other, internal engine damage.
 
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Well, mechanic told me there is a significant amount of aluminum in the oil filter (probably from the piston) and he feels the engine needs to come off and be overhauled. So there it is.

So, back to my original question. What are some good overhaul shops for a Lycoming IO-360-A3B6D?

The pricing of Corona Engines looks pretty competitive even with California sales tax (I was quoted about $18,500 or so). http://www.coronaengines.com/Engine-Overhaul Has anyone ever used them?
 
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frcabot said:
It was an official top overhaul and official bottom overhaul. Not a repair. Also, they occurred at different times.
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Apparently I was wrong. I don't have the log books with me (they're in the plane), but my backup copy shows that the bottom consisted of "Disassemble engine & inspect for prop strike. Magnaflux crankshaft & all steel parts. Zyglo case. Check for hidden damage. Counter weights worn. Replace rod nuts & bolts. Replace main & rod bearings. Replace seals, gaskets & c.w parts. Magneto inspection. See listed parts. All current AD's complied with. Reassemble engine, ready for installation."

Does that sound more like a repair or a bottom overhaul?

Not sure what the top "overhaul" looks like, but apparently the valves were not replaced. Surprise!
 
frcabot said:
At the annual inspection in August, all compressions were good (the No. 3 cylinder had I think 73 or 74) and no problems were detected.

So I'm not sure how I got from a healthy engine to a disintegrating cylinder in a couple months and only 20 or so hours of flight time, but here we are.
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I'm not even a pilot yet but am doing some research. I went by my local airport and talked to 2 A&P's concerning the quality of 50 yo airplanes, engine longevity, and costs of ownership.They both said there's no way to know without knowing how the plane was run.

When I posed some questions regarding times SMOH and STOH they both just shrugged their shoulders. They said some engines will go 4000hrs if they are rich at takeoff and you always climb straight to your cruising altitude at wot, lean it appropriately, then leave it at wot. They both said if you like to F around with the throttle, don't watch your temps, and like to do a lot of touch and goes then you will definitely get much less time.

They were both in agreement about field overhauls. They prefer to send stuff out to the factory and get Zero time rebuilds. These guys will pull a cylinder and do valve work if they know the engine otherwise and feel it will last. One pointed to the guys across the parking lot in another hanger and said "I've never seen them do a overhaul and they are some of the best mechanics I've ever seen". Everything they do starts back at zero.

This wasn't really what I wanted to hear. I've rebuilt several car engines and don't know what the big deal is. If I buy an old plane I will try to get one where the engine will last at least a few yrs (but obviously it's a gamble) and budget for a $20k rebuild.
 
2Airtime2 said:
I'm not even a pilot yet but am doing some research. I went by my local airport and talked to 2 A&P's concerning the quality of 50 yo airplanes, engine longevity, and costs of ownership.They both said there's no way to know without knowing how the plane was run.

When I posed some questions regarding times SMOH and STOH they both just shrugged their shoulders. They said some engines will go 4000hrs if they are rich at takeoff and you always climb straight to your cruising altitude at wot, lean it appropriately, then leave it at wot. They both said if you like to F around with the throttle, don't watch your temps, and like to do a lot of touch and goes then you will definitely get much less time.

They were both in agreement about field overhauls. They prefer to send stuff out to the factory and get Zero time rebuilds. These guys will pull a cylinder and do valve work if they know the engine otherwise and feel it will last. One pointed to the guys across the parking lot in another hanger and said "I've never seen them do a overhaul and they are some of the best mechanics I've ever seen". Everything they do starts back at zero.

This wasn't really what I wanted to hear. I've rebuilt several car engines and don't know what the big deal is. If I buy an old plane I will try to get one where the engine will last at least a few yrs (but obviously it's a gamble) and budget for a $20k rebuild.
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Yes, I was definitely expecting to get a couple hundred more hours out of the engine, although when I bought the plane I got a pretty good deal because of the high engine time SMOH. I figured any extra time I got beyond 2000 hours was a bonus that I really didn't pay for.

Let me give you an example using the mooney flyer valuation tool: http://www.themooneyflyer.com/valuation/M20JValuation.html

With a SMOH 0 time engine, the plane is worth $115K (as spec'ed with GTN 650, GDL 88, autopilot, HSI, etc.) (not sure whether this price is actually attainable on the market)

With a SMOH 2000 time engine, the plane is worth $86K (same specs) (again, not sure whether this price is actually attainable on the market).

That's a difference of $29-30K, about what it costs to overhaul the entire engine.

I bought the plane for about $60K, installed a new GTN 650, GDL 88, and GTX-327, and repaired the non-functioning autopilot. So the value of the plane (ostensibly) is now $86K. I'm not looking forward to overhauling the engine, but with a fresh annual and a new engine, I should be able to get over $100K, possibly over $110K if I were able to sell it immediately -- so the engine overhaul isn't really money down the drain, but rather a depreciating asset. I figure that the extra ~200 hours I got out of the engine before overhauling it is really time that I didn't pay for.

I'd be a lot more upset about this if this were a 1000 SMOH engine and I had to do an overhaul now.

Looking at comps on controller.com:

http://www.controller.com/listingsd...NEY-M20J-201/1985-MOONEY-M20J-201/1375905.htm -- $119K with an engine that is 255 SMOH, less well equipped (GNS-430W instead of 650, no ADS-B, much older transponder, etc.)

http://www.controller.com/listingsd...NEY-M20J-201/1986-MOONEY-M20J-201/1390125.htm -- $106.5K for slightly newer model with one piece belly, "new" factory rebuilt engine, comparable interior and exterior, similarly equipped (I have GTN 650 vs. 530W, GDL-88 vs. GDL-69, and newer GTX-327 vs. old KT-76A transponder, but he also adds engine monitor, digital tach, co-pilot brakes and some other goodies like stormscope) -- this one is actually a pretty phenomenal deal and the valuation tool prices it out at $135K.
 
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Sounds like you got a good deal. I've heard it's a buyers market. Good luck with whatever you decide for the engine.

I tell ya, with the bottom and top done a thousand hrs ago I might just do the #3 for now and try to get some more time out of it. Of course check everything possible with that jug off. Can't they check cam specs without going into the bottom by checking pushrod throw? Of course you can't check main bearings but if they were done 1000 hrs ago and oil changes were on time you'd think there's some good life left.

Maybe the #3 valve was a fluke. :dunno:


:)
 
2Airtime2 said:
Sounds like you got a good deal. I've heard it's a buyers market. Good luck with whatever you decide for the engine.

I tell ya, with the bottom and top done a thousand hrs ago I might just do the #3 for now and try to get some more time out of it. Of course check everything possible with that jug off. Can't they check cam specs without going into the bottom by checking pushrod throw? Of course you can't check main bearings but if they were done 1000 hrs ago and oil changes were on time you'd think there's some good life left.

Maybe the #3 valve was a fluke. :dunno:


:)
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Bottom was done 430 hours ago. The top was done 1000 hours ago. I posted the bottom entry earlier, what do you think? Doesn't look like a full overhaul.

"Disassemble engine & inspect for prop strike. Magnaflux crankshaft & all steel parts. Zyglo case. Check for hidden damage. Counter weights worn. Replace rod nuts & bolts. Replace main & rod bearings. Replace seals, gaskets & c.w parts. Magneto inspection. See listed parts. All current AD's complied with. Reassemble engine, ready for installation."

Edit: Spoke with Ben at Corona Engines (who is very, very helpful). He says the log entry doesn't indicate that a bottom overhaul was done, just a repair. A bottom overhaul involves replacing/overhauling the camshaft, which it doesn't look was done, and there are other missing items as well. So I am feeling a lot more confident that a major overhaul to new limits is the way to go.
 
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frcabot said:
So, back to my original question. What are some good overhaul shops for a Lycoming IO-360-A3B6D?
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An A3B6D has the dual magneto setup correct? If so, I might consider sending it to Lycoming as a core on an engine with the more traditional two separate magneto setup.
 
mondtster said:
An A3B6D has the dual magneto setup correct? If so, I might consider sending it to Lycoming as a core on an engine with the more traditional two separate magneto setup.
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Correct, A3B6D has the dual mags but the difference in cost at Corona Engines, for example, is like $4K or more. Not sure that's worth the difference.
 
frcabot said:
Bottom was done ~500 hours ago. The top was done 1000 hours ago. I posted the bottom entry earlier, what do you think? Doesn't look like a full overhaul.

"Disassemble engine & inspect for prop strike. Magnaflux crankshaft & all steel parts. Zyglo case. Check for hidden damage. Counter weights worn. Replace rod nuts & bolts. Replace main & rod bearings. Replace seals, gaskets & c.w parts. Magneto inspection. See listed parts. All current AD's complied with. Reassemble engine, ready for installation."
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500 hours ago? replace the cylinder and drive on...
 
Clark1961 said:
500 hours ago? replace the cylinder and drive on...
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I modified post with new info just received:

"Edit: Spoke with Ben at Corona Engines (who is very, very helpful). He says the log entry doesn't indicate that a bottom overhaul was done, just a repair. A bottom overhaul involves replacing/overhauling the camshaft, which it doesn't look was done, and there are other missing items as well. So I am feeling a lot more confident that a major overhaul to new limits is the way to go."

Basically, while the bottom was torn down and repaired as necessary, new bushings and rods were installed etc., it was not an "official" overhaul. Not every piece was overhauled, and equipment like the camshaft (apparently) that didn't need to be overhauled/repaired weren't. It certainly wasn't to new limits.
 
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frcabot said:
Edit: Spoke with Ben at Corona Engines (who is very, very helpful). He says the log entry doesn't indicate that a bottom overhaul was done, just a repair. A bottom overhaul involves replacing/overhauling the camshaft, which it doesn't look was done, and there are other missing items as well. So I am feeling a lot more confident that a major overhaul to new limits is the way to go.
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So.... Wad'd I tell ya.
 
Tom-D said:
So.... Wad'd I tell ya.
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Hey, I never disagreed with anyone. I find all of you guys super helpful when it comes to the mechanical stuff, which is way over my head. My goal is to be as knowledgeable as many of you. (Although, it does seem that opinions are like a**holes, everybody has one :-D).
 
Top was done 1000hrs ago but 25% of that went bad. Everything in the bottom was done 500hrs ago except servicing/checking the cam which was in spec 2000hrs ago.

With the (limited) knowledge I have right now I would want to check the cam and if it checked out I would do the #3 jug only for now and try to get another 1000hrs out of her.

As long as oil analysis has been coming back ok, other 3 compressions are good, and the engine has been burning the correct amount of oil I see no reason to go in and replace (again) parts with very little wear.


disclaimer: I only know engines in general, not aircraft specific, so if an expert feels my input has been dangerous please let me know and I will delete. I certainly do not want to sway anyone into a bad decision. I'm just offering my common sense thinking. :wink2:
 
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It's really a six of one/half a dozen of the other as the best way to handle this on a Pt 91 plane. Overhaul is like religion, there are a lot of paths you can follow, and they all lead to the same place. Which philosophy will be safest or cheapest is a gamble really, there are so many variables and random factors involved you have limited ability to predict service life.
 
No, not an official overhaul but that does sound pretty thorough. If the mechanic said there was a lot of metal in the filter, then overhauling it now might be worth the piece of mind. That metal did go through the engine and may or may not have caused damage to other components. Most likely it did not, but its an airplane engine and being cautious is not a bad idea.
 
dell30rb said:
No, not an official overhaul but that does sound pretty thorough. If the mechanic said there was a lot of metal in the filter, then overhauling it now might be worth the piece of mind. That metal did go through the engine and may or may not have caused damage to other components. Most likely it did not, but its an airplane engine and being cautious is not a bad idea.
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And.....

A valve is HARD metal. When one gets swallowed into a cylinder, it beats the crap out of the entire area... Also, the metal valve getting crushed is sending massive amounts of added force onto the rod / rod bearing / crankshaft and it needs to be looked at VERY closely for overload failures... IMHO...
 
The primary consideration on if you want to overhaul or do a major repair an engine is if you plan to sell the airplane soon. The closer you are to TBO, the less sense it makes to do an expensive repair since it has no residual value while Overhaul has a full scale engine value pro rate reset to the plane's value. That's why 75% TBO is the best time to buy engines since they are already priced as 'core value', but still have a good chance of giving several hundred more hours of service. You get those engine hours between then and overhaul 'for free' as long as you don't toast the core. Outside of gas, that's most people's single greatest operating expense.
 
N801BH said:
And.....

A valve is HARD metal. When one gets swallowed into a cylinder, it beats the crap out of the entire area... Also, the metal valve getting crushed is sending massive amounts of added force onto the rod / rod bearing / crankshaft and it needs to be looked at VERY closely for overload failures... IMHO...
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Its definitely a lot of force but remember its being sandwiched between pieces of soft aluminum. I've seen a lot of blown up aluminum cylinders/pistons from motorcycle racing that did not damage the rod or crank. Bikes w 13,000 rpm rev limiters you hit every couple laps. The rod and crank are very hard steel.

But... if it did really swallow the valve, and the mechanic says it had metal in the filter, and its basically at TBO from a value standpoint... probably time for an overhaul.
 
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I see runout airplanes as easier to sell than ones with overhauls, considering the present condition of the used spam can market. As such, not only is an overhaul not likely to get you your money back, nevermind the opportunity cost of having 150% of the original value on the line, it'll actually reduce the liquidity of your expected transaction. But that's my take as a "buy low sell low" type of aircraft owner, and one who values liquidity when it comes to these overpriced toys. To each their own.
 
dell30rb said:
Its definitely a lot of force but remember its being sandwiched between pieces of soft aluminum. I've seen a lot of blown up aluminum cylinders/pistons from motorcycle racing that did not damage the rod or crank. Bikes w 13,000 rpm rev limiters you hit every couple laps. The rod and crank are very hard steel.

But... if it did really swallow the valve, and the mechanic says it had metal in the filter, and its basically at TBO from a value standpoint... probably time for an overhaul.
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I agree 100%...
 
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