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Engine overhaul dilemma: What would you do?

Long story (actually my personal aviation ownership nightmare) but I’ll try to stay on point here.

A while ago, I bought a amateur-built Jodel with Continental O-200 engine. Since then I’ve had numerous issues with it, in particular with the engine. Due to excessive oil consumption (about 0.5 lph), all four cylinders were now pulled by my shop and brought to reputable engine shop, which did previous top overhauls.

Result:

  • Pistons are Lycon high-compression pistons (compression ratio 9.1)
  • Cylinders and pistons are P15 bore
  • One cylinder exceeds serviceable tolerance limits in bore, others are close
  • Valves / valve guides exceed tolerance limits
  • Wrist pin bores (or wrist pins) exceed tolerance limits

Other parts, such as crank shaft, was not yet looked at yet. I understand that it could also be affected from cylinder problems (e.g., pitting).

I’m surprised about the general condition, as last top overhaul is “only” about 250 hours (4 years) ago. But I understand that such wear is still possible, no?

In any case, extensive overhaul of the engine will be necessary. I want to get your opinion what you think is a reasonable action under the circumstances.

It appears that the value of my aeroplane is essentially zero at the moment (or maybe a few thousand EUR). As its general state is not that great, I’m concerned of pumping non-negligible money into a potential bottomless pit.

I’m basically facing the following options:

Option 1: Try to sell aeroplane as-is / sell it for parts / trash it

+ Quick end of misery, can start over again (or quit aviation)
+ Will not throw good money after bad

- Will be hard to find a buyer at all
- Will only yield a few thousand EUR at best (extensive financial damage)

Option 2: Do minimum amount of work (top overhaul with used cylinders) to fix immediate problems.

+ Less than half price than complete overhaul
+ May continue flying
+ Might be easier to sell it than with option 1
+ Might minimise financial damage

- Engine shop warned that other engine parts might be in bad shape (crank shaft)
- Engine shop warned that in few hundred hours, complete overhaul might still be necessary
- Buyers might be concerned about engine history, and that not complete overhaul was done, so danger of complete overhaul in 300 hours or so

Option 3: Do complete (zero-hour) overhaul of engine

+ Will have new engine, safest solution, no more engine problems
+ Probably easiest to sell

- Price of overhaul exceeds market price of aeroplane, so might make a net loss
- Will have a quasi-new engine in an aeroplane which is otherwise not in a great state

Option 4: Buy used / overhauled engine

+ Seems a reasonable compromise: I see quotes in USA for overhauled O-200A for $17k.

- This might be a bad idea for a reason I’m not aware of.

Based on what I wrote, what are your thoughts? And if you can think of anything else, that’d be interesting too.

Thanks for reading,

Michael

Last Edited by Zorg at 28 Jun 21:30
LFHN, LSGP, LFHM

So you got is something that is worth ZERO, and you wonder what to do with it? As little as possible is probably a good option IMO.

The elephant is the circulation
ENVA ENOP ENMO, Norway

So you got is something that is worth ZERO, and you wonder what to do with it? As little as possible is probably a good option IMO.

That’s encouraging! A real little ray of sunshine. We’re talking about an amateur built airplane here, meaning that whatever state it is in, someone handy should be able to do something with it.

But to the point, when you bought the airplane I suppose that its condition was acceptable to you, that the plane suited your purpose and the price was right for you. If the engine is the only thing preventing you from flying the plane, the question is basically what you need to do with the engine in order to make it flyable and get the most bang for your bucks – which is just what you did.

In order to have a better idea about the state of the engine, I think it would be helpful to get a little more history about it, like the total number of hours, the age, whether it went through some periods of disuse, how it was stored (hangared or not), whether it has undergone previous overhauls or major repairs etc

LFPT, LFPN

Saying an engine has been ‘top overhauled’ means only at minimum that the cylinders were pulled, inspected and found/made serviceable 250 hrs ago. On an amateur built plane with an O-200 the cost of doing this is very little, possibly the cost of a top end gasket set. So the owner may choose to do just enough to keep it going for say… 250 hrs.

Assuming the rest of the plane is in decent condition, I might plan to throw away the cylinders, disassemble the bottom end, inspect and do whatever may be required to assure its in serviceable condition (i.e. not rebuild to new). Then install a set of new cylinders for $3700 complete and fly. Your biggest cost risk in looking over the bottom end is stuff like the oil pump inspection and corrosion on the timing gears.

If you have reason to believe based on hours and documentation that the bottom end is OK (and also have taken a look for corrosion etc thought the oil sump and mag holes), leave it as-is and just install new cylinders.

Last Edited by Silvaire at 28 Jun 22:05

Since the airframe is amateur-built, you do not necessarily need a certified engine. You may be able to swap your O-200 for one that has been overhauled under approved alternative procedures, which means it’s airworthy for experimental aircraft but not for certified ones. We had such a O-200 here with this limitation written in the logbook. I don’t know where this engine is now, but I can ask.

LKBU (near Prague), Czech Republic

Aviathor wrote:

But to the point, when you bought the airplane I suppose that its condition was acceptable to you, that the plane suited your purpose and the price was right for you. If the engine is the only thing preventing you from flying the plane, the question is basically what you need to do with the engine in order to make it flyable and get the most bang for your bucks – which is just what you did.

I didn’t necessarily discuss this in this thread, but I’m going to be brutally honest:

It might be fair to say that essentially I got fleeced by the previous owner. Of course, and obviously, I mainly have myself to blame: I was naive / stupid / inexperienced, and committed the cardinal sin of buying based on promises and trust without pre-purchase inspection from a mechanic.

The previous owner is a well-known and successful aerobatics pilot and captain at a top-tier airline. I was silly enough to be impressed, believe him, and don’t worry about red flags (e.g., he couldn’t find the engine logbook — it turned up after purchase). However, many things he told me before buying turned out to be optimistic, misrepresented, or outright false, and I certainly overpaid for the plane even without the engine trouble.

The Jodel itself does fit my mission (mountain flying and some cross-country), but the build quality is quite mediocre, it has numerous other issues that need attention, and at this point I don’t have much trust in it. I’ve done about 40 hours in it since purchase, about half of them from and to repair shops.

In conclusion, my dream of owning my first airplane has become multi-year nightmare, but according to mechanics I should see the positive that the engine didn’t fail me over inhospitable terrain in the current state.

Last Edited by Zorg at 28 Jun 23:19
LFHN, LSGP, LFHM

Aviathor wrote:

In order to have a better idea about the state of the engine, I think it would be helpful to get a little more history about it, like the total number of hours, the age, whether it went through some periods of disuse, how it was stored (hangared or not), whether it has undergone previous overhauls or major repairs etc

This is from memory (log books are with shop):

  • Engine is from 1970s or 1980s IIRC
  • Earlier history is murky, but it has early-generation cylinders; also, two cylinders might have been exchanged in the past, as they are slightly different than the others (e.g., transition from wide to narrow cylinder part)
  • Engine had 2000 hours in 2001, where it was completely overhauled (zero hours) by reputable engine shop
  • Top overhaul was done by (same) reputable engine shop in 2006 at ~400 hours (cylinders were redone, but also some work on pistons and other parts IIRC)
  • Another top overhaul was done by (same) reputable engine shop in 2014 at 1250 hours (again cylinders were redone, with some misc. work on other parts)
  • Until then, engine was flying regularly at aeroclub (who constructed the plane)
  • After that, previous owner bought aeroplane, seemingly as basis for experimentation. Extended periods of not flying (months at times) followed.
  • About 30 hours ago the previous owner (himself) swapped stock pistons for new high-compression (9.1:1, P15 bore) pistons from Lycon. He did not hone the cylinders.
  • I bought aeroplane about two years ago at 1500 hours. It was hangared, but hardly flown due to technical issues.
  • Engine has now about 3500 hours in total, 1550 hours since last major (zero-hour) overhaul in 2001, about 50 hours since new pistons, about 300 hours since last top overhaul.
  • Oil consumption is about 0.5 lph. I’ve been told to use Total Aero 80 (mineral oil) during “break-in”.
  • One cylinder (#3 has much lower head temperature than the others in cruise: 90 degrees C vs. 120-130 degrees C), but also higher exhaust gas temperature (730 degrees C vs. 680 degrees C). Oil pressure is normal, oil temperature rather high (about 100-105 degrees C).
  • New spark plugs (after 10 hours), piston heads are all black and greasy.
  • During magneto check, it runs quite rough on one magneto one one cylinder (oil on bottom spark plug?).
Last Edited by Zorg at 28 Jun 23:22
LFHN, LSGP, LFHM

Silvaire wrote:

If you have reason to believe based on hours and documentation that the bottom end is OK (and also have taken a look for corrosion etc thought the oil sump and mag holes), leave it as-is and just install new cylinders.

The engine shop has mentioned the possibility of swapping against their stock of overhauled cylinders. That should be ok too, no, or is there a big advantage of using factory-new cylinders?

Does it make sense to keep the high-compression Lycon pistons, or will it be safer to put back new stock pistons?

Last Edited by Zorg at 28 Jun 23:27
LFHN, LSGP, LFHM

LeSving wrote:

So you got is something that is worth ZERO, and you wonder what to do with it? As little as possible is probably a good option IMO.

I agree with the general sentiment (not throwing good money after bad), but I’m wondering whether resale situation might be a little more complex. So it might be a better “investment” in terms of resale value to spend a little more?

To reiterate my thoughts (correct me if I’m wrong):

  • Cheapest solution (sale aeroplane as-is, with defect engine) might make it hard to sell, and at firesale price.
  • Middle ground (minimal work to make to fly again) might yield more interest, but people might be concerned about remaining engine life, while it’s still not a “cheap” option.
  • Most costly solution (complete overhaul) might make it well sellable, but cost of overhaul exceeds anticipated resale value and is serious cash outlay for me.
  • Swapping with a used low-/middle-timed engine might be a good compromise, but also be a gamble on engine quality from afar.
Last Edited by Zorg at 28 Jun 23:38
LFHN, LSGP, LFHM

Zorg wrote:

The engine shop has mentioned the possibility of swapping against their stock of overhauled cylinders. That should be ok too, no, or is there a big advantage of using factory-new cylinders?

Does it make sense to keep the high-compression Lycon pistons, or will it be safer to put back new stock pistons?

Overhauled cylinders may well be fine, but in recent years the new cylinders coming down in price (to under $1000 USD each) have to a great degree displaced them.

I’d go with stock compression pistons myself, particularly if running on Mogas.

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