Overhaul that is 25 years old

[thomas1142]

What are the views on an engine that has 1200hrs, on an overhaul that is 25 years old?

[Bob_Belville]

With just that info and no more details I think most folks would suppose the engine will not likely go another 800 before needing overhaul. What engine? What else do you know about how the plane was flown - years of sitting or a steady 50 hours a year? The old cliche of rusting out, not wearing out is certainly valid for aeroplanes.

[aaronk25]

Price it as it's needs a motor. Zero value except what the core is worth.

[cujet]

As a mechanic, I still see a few Lycoming engines that are 40 years old, and seemingly airworthy (however, without disassembly, it's very difficult to know the actual internal condition) . My 200HP Lyc was installed in 1975 (or 74) and made it until 2007, when the camshaft finally failed. 1700+ hours since new. Upon disassembly of my engine, many parts were scrap due to corrosion. Including the cam, rods, gears and so on. 

 

If this is an aircraft for purchase, the engine needs to be considered "timed out" for pricing purposes. I'd bet a dollar that if the engine in question were disassembled, it would be in need of an overhaul. If only because there is internal corrosion on the connecting rods, crankshaft counterweights, camshaft bits, and possibly cylinder corrosion. 

 

Remember 12 years is the Lyc recommended overhaul period. 25 years is beyond double! Without proof the internals are perfect, the engine needs to be considered as timed out. Below is a pic of why time is a huge factor. 

 

 

Let's look at this another way. Our air cooled engines have plenty of combustion "blow by". This carries lead salts into the oil, as a byproduct of burning 100LL Avgas. Those lead salts are corrosive in nature. Couple that with the significant moisture created by combustion and the engines internals are bathed in a acidic corrosive mixture of water and lead salts. Oil change intervals and usage habits play a very large role in the corrosion equation. 25 years of low utilization significantly increases the possibility of internal corrosion. 

[AmigOne]

In 2007 I purchased a 1977 Cessna 172, 1200 TT since new with some things I wish I had now now (430 and Stec 55 with GPSS, in-panel traffic alert) and fantastic interior and paint, custom panel, etc. All around 8 out of 10.   The overall condition and investments made in that airplane made me believe that the engine would not be a factor and I bought it on the spot without a pre buy (I know, crazy).  And it didn't, it performed flawlessly for about 300 hrs until I sold it just before prices began to drop. The airplane was sold to a friend of a friend in south america and until a couple of years ago it was still flying with the same engine.  However a lot a people at the time thought it was insane to fly an airplane with an engine that old.  My lesson here is that engine time alone is not only the sole indicator of future performance.  It is a good negotiating issue to try to bring the price down. 

[carusoam]

In an ideal situation, a well cared for engine does not have an age limit... (Private plane, personal use)

What do you know about the care of this particular plane?

The value is in the discussion....

Know what a PPI is.

Decide how much to spend on a PPI to meet your requirements.

Then decide on how much financial risk you are willing to take.

Pricing it as 'run-out' is good in theory, but when a second serious buyer starts looking at it, that theory will leave you with a lesson in market forces.

You have heard from some truly experienced owners above.

Does that make sense to you?

If it does you are ready for ownership...

Best regards,

-a-

[N201MKTurbo]

If you are thinking of buying this engine I would have them pull the cylinders on one side. This will allow all the lifters and the cam to be inspected along with all his rods and cylinder barrels. Then have them pull off both mags to inspect the accessory gears. If no parts are needed this will cost about $500. Cheap insurance.

[AmigOne]

FWIW just found this brief article in AOPA's newsletter 

 

http://blog.aopa.org/opinionleaders/2014/07/02/what-makes-an-engine-airworthy/

[1964-M20E]

Use it as a bargaining chip in the negotiations on the price of the plane.  If you buy it fly it like you stole it.  Keep a close eye on it especially the first 50 to 100 hours for most of us that will be 1 to 2 years after that enjoy it until it starts talking to you.

[thomas1142]

Great info. Thank you all!

[WardHolbrook]

Let's not forget that the OP said it had been 25 years since the engine's LAST overhaul. Twenty five years and 1200 hours on a first run (new) engine is one thing, 25 years and 200 hours since an overhaul is something completely different or at least very well could be. Which overhaul - the first? The second? The answer to that question is going to have a huge impact on the financial risk and overhaul costs the next time around. In my humble opinion, he has absolutely no other prudent choice but to assume that engine is run out  and make his offer to the seller accordingly. Now I realize that will probably PO the seller, after all, it's his "baby" and of course, there's absolutely nothing wrong with that engine. (That's what they all say.) That's all well and good, but it is what it is. Let someone else be the one who over pays for the airplane, then finds that he's way upside down in it after he finally gets all of the engine issues resolved. In other words, keep moving folks, there's nothing to see here.

[AESpecialists]

  Lycoming (and Continental for that matter) set a calender TBO of twelve years for a reason beyond the simple desire to sell parts.

 

  There is the corrosion issue already mentioned. There is degradation of rubberparts like oil seals, pushrod tube seals, mag drive cushions, etc., and perhaps most important is the backlog of AD's and SB's that may never have been complied with. Never assume that they have been done. We had an engine come through once that had a 61 year old outstanding AD on the camshaft.

[cliffy]

Welcome AESpecialists   Glad to have you participate on the forum.

[mcpilot]

Oil analysis and inspection of filter would be important here after the engine has run.  Lycoming IO 360s do not fare well if they sit and the cam and lifters have a chance to corrode... The wear will snowball at that point...

[cujet]

Be aware that an engine can have a beautiful patina of rust on the connecting rods, crankshaft, accessory drive gear set, and other internal parts, yet still operate perfectly. And, it even may last for 30 additional years. Or that rusted connecting rod could snap on the next flight.....

 

Put another way, how an engine runs is not an indicator of internal corrosion, with the exception of a completely worn out cam lobe or lifter. Lack of valve lift will reduce power! However, my engine with the cam lobe pictured below ran fairly well and performed darned close to normal at altitude. 

 

[fantom]

...However, my engine with the cam lobe pictured below ran fairly well and performed darned close to normal at altitude. 

 

 

 

Are you trying to dissuade 'rusty' mass hysteria and cost engine rebuilders lots of business?

 

Good post!

[pinerunner]

FWIW just found this brief article in AOPA's newsletter 

 

http://blog.aopa.org/opinionleaders/2014/07/02/what-makes-an-engine-airworthy/

Another great article. At first I was going to say that I was happy to see another expert like Busch, then I saw his name at the bottom. It does make it clear that we have a lot of tools these days to help make good decisions. We just need to put them to work. I really liked N201MKTurbo's advice that pulling three cylinders and a few accessories gives good cheap access to the interior if you're feeling antsy about the state of your engine. Of course if you go past TBO you've got to be ready to do the big overhaul at some point and be sure you don't wait to long.  However, if you think that's not already the case just because you HAVEN'T gone past TBO then you're a fool. Hope I didn't hurt any feelings.

[Wakeup]

I know an oil analaysis with every oil change will show trends for wear and tear but will it ever indicate action that needs to be taken?? I have an older engine with around 1,000 hours and all of these posts are making me think I need to tear my engine apart. The more I am educated the more I am scared to fly. Especially when a plane crashed yesterday 10 miles from my airport and it was a newer plane. Sounds like engine failure. He told aprroach oil was all over his windshield minutes before he crashed. Troy

[AESpecialists]

  By knowing what bits are made of what metals, oil analysis, or rather a sudden change in the results, can hint at what may have failed.  A spike in lead / tin indicates failure of a main or rod big end bearing pretty conclusively, since there's nothing else with those elements. A spike in copper /and or brass is likely to be a rocker arm bushing. It could also be a  rod small end, piston pin plug (possible bent or twisted rod)  or, on Continentals, the starter adapter or accessory drive shafts as well. On Lycomings a spike in iron/steel is most likely a cam failure in the works, but never a good sign at all.

 

  Lycoming cam failures will telegraph themselves with steel specks imbedded in the piston skirts, so if you have a cylinder off for any reason look there.

[Wakeup]

Thanks for all the information. Do you think it's worth the money and time to pull the engine apart and look for signs of failure ? Thanks. Troy

[carusoam]

Troy,

Consistent oil analysis is the first step.

If you get high levels of any metals, a second step will depend on what you see in the oil analysis.

It is not necessary to assume doom is coming to visit.

Even new engines have their issues.

Keep training to at least be ready for various failures.

The constant talk of failures is meant to educate the Mooney community of how to handle the various mini disasters that are possible.

They are not intended to induce fear. Nobody will benefit from pilots being too scared to fly.

My biggest fear early on was that I would not be able to afford to remedy a mechanical issue. Fortunately a stuck valve doesn't cost too much...

Have you been to a MAPA training?

Best regards,

-a-

[AESpecialists]

  Like has been said, no intent of fear-mongering. 

 

Our experience as an engine shop  is a little different than the average mechanic, because, other than simple TBO overhauls, we see many more major or catastrophic failures.

If it's an easy fix, or a simple thing, it doesn't make it's way to us.  I suppose it's like a surgeon vs. a family doctor. We don't treat the sniffles<G>