There is nothing unusual about the situation with this plane & engine except that it seems to have been falsely advertised as having 146 hrs SMOH. Then in response to your direct question the vendor tells a story on hours and years that is less than forthright. It reminds me of the comedy routine about politicians where the answer to a question is “I’ll answer that, but first let me say this” (without ever answering the original question) . Hopefully in either case the audience understands what that kind of answer indicates.
Other than that, the situation reflects the standard routine for many aircraft owners: trying to avoid the expense of a major overhaul when a quick top end overhaul will give the engine hundreds more hours. Prices of new cylinders have come down a lot, so the usual routine for a top overhaul in 2019 is to simply install a brand new set of cylinders. That appears not to be the case with this engine, and it may indicate (or not) that the work was done on a very tight budget to keep the engine going a bit longer before an anticipated major overhaul… possibly by the next owner 
Calendar time between mandatory overhauls is a European government regulatory concept. Continental is a commercial company that simply recommends overhauling the engine every once in a while regardless of hours, and doesn’t get into all kinds of crazy detail about inspections and extensions and approvals. Continentals regulatory authority on this issue in the US is zero, so for most owners of these engines calendar time doesn’t enter into the equation. Don’t look for a definitive answer from Continental, the FAA type certificate or any other informed source – the issue is (literally) foreign to them.
Re field overhaul, this is a complete major overhaul performed by an A&P mechanic, not a repair station, with equal regulatory standing under FAA regulations. A top overhaul is not a major overhaul, regardless of whether that non-existent major overhaul would have been done at a repair station or by an A&P mechanic in the field.
Should the top overhaul be accompanied by a list of things done? Or is the procedure fully specified?
The definition of an engine overhaul (including the subset which is a cylinder overhaul) is to disassemble, measure and bring to Continental service limits or better. It is possible to overhaul a cylinder without replacing any parts at all, if nothing is completely worn out… So yes, a record of parts replaced and machine work performed is necessary if the logbook entry is to have value.
How much this particular engine type costs to major overhaul is unknown to me.
PS I should amend my response above to say that while in principle engine overhaul means bringing all wear to within service limits (an overhaul is not rebuild or remanufacture to new limits), there is also a separate, parallel regulatory requirement that requires manufacturer documentation to be followed.
For Continental engine overhaul, this means compliance with a service bulletin that for these engines specifically dictates certain parts replacement regardless of condition – and the list of parts within the cylinders in quite complete. However, the mandatory parts replacement list is applicable “at engine overhaul” and since the engine SMOH hours do not change after top overhaul, top end work is engine repair, not overhaul. With that in mind, I would not greatly value a cylinder overhaul logbook entry unless further parts and machine shop documentation were provided.
@Snoopy
Some food for thought:
https://www.savvyaviation.com/wp-content/uploads/articles_eaa/EAA_2010-02_engine-tbo-a-myth.pdf
https://www.avweb.com/news/savvyaviator/187037-1.html
Snoopy wrote:
So the engine was not overhauled to zero but “field overhauled” resetting the calendar and hours TBO. The engine total time continues to count. . .
Now obviously it’s not the owners problem what will be done (commercially) with the plane by whoever purchases it, but do you think the “field overhaul” is already considered in the asking price?
My earlier quotes were based on the wrong assumption that the engine had been recently OH’d which happens not to be the case (only a repair including a top OH and a lot of the accessories which, honestly, makes me like the engine subject to the other caveats discussed). Since the ‘top end’ (cylinders) were taken care of at that repair, my main concern (for private use) would be “bottom end” but that can be addressed as discussed earlier. For commercial use it is the calendar time since OH that is a concern.
As discussed by others, no ‘zero’ timing at all. I have not seen a quote as to the actual hours TSO and date of OH. Based on that, you should adjust the value. A reasonably good OH of this engine is around EUR50k+-5k depending on accessories. So if actual TSO is 800hrs (half life) then you should lower the ref price by around EUR25k. Calendar time SOH does not impact the time so much, but the actual value depends on the checks I suggested before.Worst case it could be 100TSO but 20 years old and completely corroded inside which would give you zero value for the engine. It does not look the case here.
Snoopy wrote:
I’d think a pressurized plane with retractable gear brings more potential for expensive snags. It might not be much more expensive per nautical mile though due to higher speed and similar fuel flow.
All true cost-per-NM wise. Not cost per h. You can perhaps budget 25-35 EUR/h delta but it depends very much on the history of your individual airplane.
As to retrofitting deicing, prop deicing is feasible but you would have to get salvaged parts for most of the items, If the Parts catalogue lists it for your airplane then you should be able to install it using it as approved data. The issue is finding approved salvage parts. If you really want deicing, I would check if the TKS STC applies to your aircraft and evaluate it as an alternative.
As to retrofitting radar, I would not recommend it. I dont know if it was an option for your airplane, but it is a complex route and an ADL from Golze will provide in most cases equal or better utility except for detail short-range avoidance…but you do not want to be doing that near a storm in the Alps anyway. Better fly before or after storms populate the mountains.
If I were you, I would take a good mechanic with me, go fly the airplane, inspect it including our earlier suggested checks and, if all is good, make any required adjustments to the price and, if agreed, immediately pay a deposit on it.
Dont forget to find out the actual engine TSO & date of OH
Thank you very much! Let’s see how it goes ;)
I’m slightly confused by the “zero-time” discussion. Is there any difference from a maintenance/operational point of view between an engine which has been “zero-houred” and an engine which has “just” undergone an overhaul according to the manufacturer’s instructions?
Snoopy wrote:
The ad says
Engine TT 2710h
Engine TSO 146h
Last engine overhaul 05/2015
Remaining time on engine Until 05/203
This is a bit misleading… instead of TSO it should say “Since last repair/top overhaul” etc…
That is the question and it HAS to be completely answered to find out where you are with it.
TSO means for me since an overhaul which resets TBO both calendar and hours, particularly the next sentence “Last overhaul” would indicate a field overhaul at least, otherwise the remaining time would be wrong.. A top overhaul alone is NOT reason to write TSO, that information would not only be misleading but false. Yet preciously many sellers have no idea about this and copy others who have but really want to cheat.
There is no other way than take the whole documentation to a savvy guy at a CAMO or other maintenance organisation and let them go over it with a fine tooth comb. THen you know where you are, before that everything else is guesswork.
