When is a tear down more overhaul than not?

[Schllc]

The first thing I should say is I know that unless it’s an overhaul it’s not an overhaul. 
But, as i was reviewing the logs of my acclaim again, just for curiosity sake.  It reminded me that I meant to pose this question when I bought it. 
The previous owner had a gear up landing and the engine was sent to a very reputable shop for the sudden stoppage tear down. 
Per the repair ticket, they replaced the cylinders, pistons, connecting rods, lifters, cam and crank, all with new or reman parts. 
They also changed all the bearings and bushings, rebuilt the mags and changed the alternator and starter adapter as well as both turbos and rebuilt the exhaust.   
Doesn’t this seem like an overhaul to anyone else point being it is not, and cannot be represent as such, but why wouldn’t you if all this was done?

flame away!

[Pinecone]

Here is the AC definition of Major Overhaul:

c. Overhaul. In the general aviation industry, the term engine overhaul has two identifications (second is top overhaul) that make a distinction between the degrees of work on an engine:

(1) Major Overhaul. A major overhaul consists of the complete disassembly of an engine. The overhaul facility inspects the engine, repairs it as necessary, reassembles, tests, and approves it for return to service within the fits and limits specified by the manufacturer’s overhaul data. This could be to new fits and limits or serviceable limits. The engine owner should clearly understand what fits and limits should be used when the engine is presented for overhaul. The owner should also be aware of any replaced parts, regardless of condition, as a result of a manufacturer’s overhaul data, SB, or an Airworthiness Directive (AD).

Link to AC - https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_43-11_CHG-1.pdf

[PeteMc]

When I was looking to purchase my plane it was being listed as XXX hours since Overhaul.  It too showed all sorts of work had been done, but not everything to give it that "Overhaul" badge.  The mechanic reviewing the books for me noted that some perfectly good original or used parts were put back into the engine that did have the right Tag to be considered New or Like New or whatever the magic word is to use it in an "Overhauled" engine.

Mechanic thought all the work and the log entries were top notch.  But it just didn't have what it took to call the engine overhauled and restart the clock.  So I ended up getting a hefty discount on the asking price and basically got an "almost" rebuilt engine.

 

[N201MKTurbo]

Lycoming and Continental have a list of mandatory replacement parts for an overhaul. If all those parts were replaced and everything was inspected, then you could call it an overhaul. 
 

But we are part 91. You can pretend it was an overhaul and nobody will hold it against you. The only issue would be selling it and claiming it was overhauled.

[Schllc]

I would not claim it was an overhaul.  That would never go in your favor because it would be a misrepresentation. 
It’s more of just a curiosity, because of what was changed. 
I would  think if it was me making the decisions after a prop strike, and they did this much work, I would say just finish the overhaul. 
I honestly can’t think of anything else that would need to be done..

[M20F]

When I did my engine for the first time I completed everything for a major overhaul sans new exhaust valve in a cylinder with 4.5hrs on it.  I would say that is about as close as you can get without getting it. 

[A64Pilot]

Insurence company won’t pay for an overhaul for a prop strike.

Ergo no matter what was done, it’s not an overhaul.

FAA definition of an overhaul

FAR Part 43.2(a) says an overhauled product has been "disassembled, cleaned, inspected, repaired as necessary, and reassembled ... and tested in accordance with approved standards and technical data ... acceptable to the Administrator which have been developed and documented by the holder of the type certificate ...".

https://www.law.cornell.edu/cfr/text/14/43.2

I do not have to change parts to overhaul an engine, if everything meets serviceability criteria, I can put it all together and sign it off as overhauled. That would be rare, but not all that un-common.

This is why there are good overhauls, and not so good overhauls because experience has shown that for a good reliable engine as a min certain parts are replaced with new, but it is NOT required. Overhauls that just meet legal requirements are not so good, legal yes.

Lycoming and Continental do have SB’s that list mandatory replacement of certain items, but guess what, SB’s aren’t mandatory, smart, but not mandatory.

So it’s entirely possible your engine could have been signed off as overhauled, but we are back to insurence company will not pay for an overhaul for a prop strike.

So why were all those parts replaced? For one most likely there is an SB that says when disassembled x parts will be replaced and insurence will pay for SB compliance, and secondarily when a mechanic disassemblies a component they have to determine serviceability of the components and we can’t put un-airworthy parts back in an engine.

Thats something that has been argued here adnauseum, but trust me any mechanic that doesn’t inspect parts and puts engines together from un-airworthy parts will soon be in trouble, even though I’m sure there are some that do.

[N201MKTurbo]

I loaned my plane to someone who taxied off the runway and the prop hit the runway when one wheel went off the pavement. The insurance company wrote me a check for the engine inspection. I told the engine shop to overhaul it and bill me whatever excess was needed beyond what the insurance was paying. It cost m4 $2500 if I recall. The insurance company knew what I was doing and had no problem with it.

[Schllc]

48 minutes ago, N201MKTurbo said:

I loaned my plane to someone who taxied off the runway and the prop hit the runway when one wheel went off the pavement. The insurance company wrote me a check for the engine inspection. I told the engine shop to overhaul it and bill me whatever excess was needed beyond what the insurance was paying. It cost m4 $2500 if I recall. The insurance company knew what I was doing and had no problem with it.

That’s kind of what I was getting at. 
what’s left to “overhaul” after all that was done?

answer… not much…

[A64Pilot]

20 minutes ago, Schllc said:

That’s kind of what I was getting at. 
what’s left to “overhaul” after all that was done?

answer… not much…

That’s why I tell people that if they are removing the engine, splitting the cases etc. that it’s likely that it makes sense to complete the overhaul, and reset the clock and add value to the aircraft, especially if it’s a mid time or later engine or is over a decade since overhaul.

Its at least worth asking how much

[carusoam]

Given the opportunity once…

1) Much of the decision came down to how many hours were on the engine already…. Is it getting close to needing an OH…

2) How much dough the insurance company is offering…. Apply it to the tear down, or the OH…

3) Where do you want to end up… OHing when the time comes… or get it over with now…

4) Prop upgrade desired?

5) 310hp desired?

6) Timeline… the prop takes a lot longer time to build then a factory remanned engine…. Several months….

7) Insurance paid for the R&R, and prop, + estimate of what the tear down costs….  end user paid for the choice of OH… 310HP STC was extra….  
 

8) Every situation will be different… the insurance company has a word they use, called Betterment, to be familiar with…
 

All this fun was a decade ago….  
 

The plane in question was restored to full functionality, with the least amount of fear going forwards… zero timed factory reman…  there is still plenty of fear of infant mortality to go with that…

Following the guidance of MSers that have been down the same path prior….

Got introduced to people from Continental, Hartzell, and the 310hp STC writer…

Discussed things like…

1) WnB changes

2) TopProp blade selections, materials and profiles…

3) Engine / cylinder choice  N or G…

4) Tach update, how best to move the red line…

My chances of OHing an engine like this… would require knowing Rich was working on it, or leading the effort….   

People, product, procedures…. All are important.  Engine OH adds a whole new level of detail…

The costs are too high and don’t allow for any do-overs….

PP thoughts only, not a mechanic…

Best regards,

-a-

[jlunseth]

A little off the subject, but I am putting a new Conti in my plane this winter. I wanted a factory reman, but it turned out the difference in price was not very much between reman and new, much less than it was a few years ago. Difference was about 8 AMUs as I recall, maybe less. New means everything is new including the accessory systems. The existing engine is 20 years old. I couldn’t see doing a field OH on an engine that old and having the plane down for maybe 6 months for it to happen. I like to actually fly on occasion.