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Newly Overhauled Engine, No Existing Logs?


trecool44

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Hello,  I am looking to buy an overhauled engine (not my current engine) from a local long time AP for my M20C.  He did the field overhaul himself.  He does not have the engine logs previous to the overhaul.  What issues does this cause?  Value,  A/D compliance issues,  total time carry forward?  Please let me know what you think.  Thank you so much.

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Hello,  I am looking to buy an overhauled engine (not my current engine) from a local long time AP for my M20C.  He did the field overhaul himself.  He does not have the engine logs previous to the overhaul.  What issues does this cause?  Value,  A/D compliance issues,  total time carry forward?  Please let me know what you think.  Thank you so much.


If I am not mistaken, only the engine manufacturer can zero time an engine so without the original logs, it would be impossible like you mentioned, to determine the time on the engine, the required AD history, etc. I’m sure one of the IAs will come along with an expert opinion.


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If he has complete records of the components he used to build the engine, that alleviates SOME of the concern. I wouldn't worry too much about time on parts except for the cylinders. I'd want to know if the crank was ground/undersized. I would want records of the case overhaul, crank inspection, etc. If he just took some old stuff apart, looked at it, measured some, and put it together with new rings and bearings I would stay away. I wouldn't want cylinders with more than one TBO run on them. The rest of the parts should be fine if they were inspected well and documented.

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"Missing" engine logs are not a big deal and is not uncommon for large shops.

It is true that only the factory can '0' time an engine as brand new, but that isn't an important number.  Time since overhaul is the only number that matters since there aren't any life-limited parts on one of our engines.  The parts are either good, or they're not.  An engine overhaul should have airworthiness tags for all components with the exception of standard hardware.

This is an important consideration regarding parts: what is the engine, really, other than a collection of airworthy parts assembled together?  Every single part of your 50 year old engine could have been replaced over the years, to include the crankcase that has the serial number.  Does it really matter that the crankshaft was reground 30 years ago if it was replaced with a new one 10 years ago?

ADs on our engines must all have been complied with, but again, this will be shown in the engine logbook.  Many of these ADs are doubly important because they become effective when the case is opened for any reason.

As an example for why all-original logs for an engine aren't very important is if you were to exchange your engine for a freshly overhauled one from a large shop.  Odds are you will get a new logbook that documents the overhaul in extensive detail but you will have absolutely no data for its previous life.  Obviously, this would not be the case if you had your personal engine overhauled. The shop overhauling your engine wouldn't even care to see your previous logbooks, they would just give you a brand new one.

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1 hour ago, Ah-1 Cobra Pilot said:

How much do you trust the guy who did the overhaul?  The engine is worth exactly that much.  It is also true for whomever you might sell it to.

Personally, unless there are extenuating circumstances, I do not put much trust in someone who gets rid of previous logs.

One has to place trust in any person or institution that performs an overhaul...field or otherwise.    If this engine was rebuilt to new limits then all of the critical parts in the engine have been measured, resurfaced, repaired or replaced in order to meet factory specs.  So what is the impact of not knowing what happened before all of the internals before parts were sent out to be measured and refinished and tagged?  What info are we missing?  As Andy said, the factory would call this a "Zero Time" engine (because they've no clue about the age or hours on their serviceable parts).  So we don't know how many hours on the Cam, Crank, Case, Cylinders and all of the other moving parts that can be reused.  However, we do kno that they've been measured and inspected and meet whatever spec the engine was built to.  All other things being equal, this is not really a safety issue. Everything part has been vetted.  The two exceptions I would want to verify is that the installed cylinders were new and that the crank case was sent out for overhaul (this does not always happen with FOH's but should in my opinion).  I would try and negotiate (I always do) a discount because this engine has a "story" (as in lack there of) but I'd be no less inclined to fly behind it because of logs missing from its previous life.  

It's funny to me that pilot's will list "zero time" as a selling point when the factory puts unknown parts in an engine, but god forbid it's done by a pro in the field... then it's a time bomb.

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The most common failure in a Lycoming engine is the camshaft and lifters, are they new?  Are there tags for the other components, records of measurements, records of service bulletins and letter complied with at overhaul.

The devil is in the details.

Clarence

 

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IIRC, the only regulatory requirement for maintenance logs is keeping records of work done only within the past 12 months, and only if the work was not superseded by other work.  Otherwise, it can legally be disposed of.

That being said, I certainly think the lack of a good paper trail would detract from the value of an airplane, I heard by as much as 30%.  From an engine, though I don't know.  I'd certainly want to know something about the history behind a field overhauled engine, though

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1 hour ago, Shadrach said:

It's funny to me that pilot's will list "zero time" as a selling point when the factory puts unknown parts in an engine, but god forbid it's done by a pro in the field... then it's a time bomb.

I agree with everything you said. However, like any other industry/contractor/etc, there is a HUGE variance in the quality “pro’s” produce.  No paperwork and probably trying to do it as cheaply as possible?  Not sure I’d want to jump in behind that engine. 

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It all comes down to how well the present overhaul is documented. A very detailed listing of what was done and what parts were replaced/reworked goes a long way to peace of mind. If all the new log says is "Engine Overhauled this date" I personally wouldn't touch it no matter who did it. When I did mine, I have 2 pages of detail on every item that went into the engine. 

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9 hours ago, MIm20c said:

I agree with everything you said. However, like any other industry/contractor/etc, there is a HUGE variance in the quality “pro’s” produce.  No paperwork and probably trying to do it as cheaply as possible?  Not sure I’d want to jump in behind that engine. 

Perhaps.  I've seen some shoddy work over the years, but most IAs that would undertake an engine overhaul are pretty serious folks. I would also submit that an O360 A1D is about as simple as a multi cylinder engine gets.  The parts get sent out, tagged and reassembled to spec.  There are no surprises, no confined spaces to deal with,  no "airframe specific" quirks to misunderstand.  Just a simple, air-cooled, 4 cyl with easy access to everything when on the stand.   I'd be far more skeptical of something like a GTSIO 520 that was field overhauled, but I've also seen those rebuilt in the field to a high standard.

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6 minutes ago, cliffy said:

It all comes down to how well the present overhaul is documented. A very detailed listing of what was done and what parts were replaced/reworked goes a long way to peace of mind. If all the new log says is "Engine Overhauled this date" I personally wouldn't touch it no matter who did it. When I did mine, I have 2 pages of detail on every item that went into the engine. 

Agreed, but you can say that about any overhaul.  The case here is lack of pre-overhaul logs.   Not knowing that the engine was serviced with 8qts of Phillips X/C in the Dec of 2006 means nothing to me.  I know many of you will mention prop strikes, but the reality is that many go unlogged. Moreover, the overhaul process goes way beyond what is required by SB533C.

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I think this may clear up some of the issue, basically Overhauled are the easy repair with limits involved,  Rebuilt are back to factory new specs (much closer limits/tolerances)  

So to answer the question, if it is well documented and is a good price, buy, install and fly.

i. Overhauled. Describes an airframe, aircraft engine, propeller, appliance, or component part using methods, techniques, and practices acceptable to the Administrator, which has undergone the following:

(1) Has been disassembled, cleaned, inspected, repaired when necessary, and reassembled to the extent possible.

(2) Has been tested in accordance with approved standards and technical data, or current standards and technical data acceptable to the Administrator (i.e., manufacturer’s data), which have been developed and documented by the holder of one of the following:

j. Rebuilt. Describes an aircraft, airframe, aircraft engine, propeller, or appliance, using new or used parts that conform to new part tolerances and limits or to approved oversized or undersized dimensions that has undergone the following:

(1) Has been disassembled, cleaned, inspected, repaired as necessary, and reassembled to the extent possible.

(2) Has been tested to the same tolerances and limits as a new item. 

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5 hours ago, cliffy said:

It all comes down to how well the present overhaul is documented. A very detailed listing of what was done and what parts were replaced/reworked goes a long way to peace of mind. If all the new log says is "Engine Overhauled this date" I personally wouldn't touch it no matter who did it. When I did mine, I have 2 pages of detail on every item that went into the engine. 

I agree fully, but that is exactly what a Lycoming overhaul show.  No details to share with the purchaser, it must be secret stuff.

Clarence

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3 hours ago, jetdriven said:

Right. Yours was a remanufactured engine. Mine was an overhaul. I think they’re the same thing really, you just pay a little more for the zero time and the longer warranty.  

Well, technically a reman/rebuilt engine is potentially a Frankenstein of old parts from any number of different engines each of which have been inspected and combined to make a rebuilt engine, along with any required new parts.  Since the old parts are de-identified, there's no way to track the history of any of them anyway, so it makes sense to zero-time the engine

Any overhaul (field or otherwise), is going to be using parts from the old engine and any new parts necessary.  That means ALL the old parts come from one old engine, so they do have a history of total time that can be tracked.

I've seen an argument that since a overhauled engine would potentially have more new parts than a rebuilt engine (since the rebuilt can take parts from multiple old engines), the overhauled engine could be more prone to infant mortality failures than a rebuilt engine.  I have to admit, I don't think there has ever been any study into whether that is actually the case.

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28 minutes ago, jaylw314 said:

 

I've seen an argument that since a overhauled engine would potentially have more new parts than a rebuilt engine (since the rebuilt can take parts from multiple old engines), the overhauled engine could be more prone to infant mortality failures than a rebuilt engine.  I have to admit, I don't think there has ever been any study into whether that is actually the case.

For me it wasn’t a choice. After my engine failure there were not enough pieces left to be considered a core and certainly no parts to contribute to an overhaul. Not many choices when you don’t have a core. Lycoming reman arrived within a couple weeks and I was able to get back in the air and fly home. 

The previous engine had been a factory NEW with 1050 hours sfnew  

-Robert

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3 hours ago, cbarnes403 said:

I think this may clear up some of the issue, basically Overhauled are the easy repair with limits involved,  Rebuilt are back to factory new specs (much closer limits/tolerances)  

So to answer the question, if it is well documented and is a good price, buy, install and fly.

i. Overhauled. Describes an airframe, aircraft engine, propeller, appliance, or component part using methods, techniques, and practices acceptable to the Administrator, which has undergone the following:

(1) Has been disassembled, cleaned, inspected, repaired when necessary, and reassembled to the extent possible.

(2) Has been tested in accordance with approved standards and technical data, or current standards and technical data acceptable to the Administrator (i.e., manufacturer’s data), which have been developed and documented by the holder of one of the following:

j. Rebuilt. Describes an aircraft, airframe, aircraft engine, propeller, or appliance, using new or used parts that conform to new part tolerances and limits or to approved oversized or undersized dimensions that has undergone the following:

(1) Has been disassembled, cleaned, inspected, repaired as necessary, and reassembled to the extent possible.

(2) Has been tested to the same tolerances and limits as a new item. 

So then how many “service limit” overhauls have you seen? If memory serves, every FOH I’ve seen has been done to new limits.

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So @trecool44,

The seller of this engine, being the respected person doing the OH...

Can he share with you the mound of paperwork he has collected while ordering parts and services for this fine collection of bits and pieces..?

All the key parts have serial numbers.  Any work on the parts gets a tag to release it from the quality group...

Recently an engine AD came out on all Continental IO550s...  If you could look up the part used in the engine, you were good to go...

If you don’t have a reliable list of parts for your engine with serial numbers on it, you were paying somebody to tear the engine down to access the part to find out if it was the bad one or not...

Often, the engine case gets sent out for service during the OH process.  It comes back with a full description of everything that was done from cleaning to welding...

You want to avoid accidently buying a case that has a crack in it that can develop into an oil leak later on...

What cam is in there? some have a history of not being the highest quality of material.  Others have been updated with oiling improvements...

Was anything added like Ney oil nozzles?

So, not having any logs can be mitigated to some extent.  It just takes a ton of documentation to do it properly.

The usual progression for engines missing logs and documents... airboats.

Always a good idea to check with the mechanic who will be doing the annual on your plane.  If he says he is OK without having all the logs... he is the guy that needs to sign off your annual.  If he balks, no signature for the annual, not current... now how do you fly?

With a heavy dose of fear of needing to sell in the following year... I went factory reman.

PP thoughts only.  Not a mechanic. mostly stuff I read on MS.

Nest regards,

-a-

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