does this constitute a major overhaul?

[SixPapaCharlie]

139 SMOH (Bottom End Only!)
81 Since Top Overhaul

 

[Norman]

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.

Therefore, NO.

 

[kyleb]

I think from the book definition, no. From a practical standpoint, probably so. After all, they did go through the entire engine within about 50 hours.

That said, I'd worry that the owner was trying to cut corners when s/he only did the bottom end, and that a certain element of "frugality" went into the rebuild. With that in mind, I'd need to see all of the paperwork - dimensions and the like, to make sure they didn't <effectively> tear an engine apart and rebuild it to "well worn" condition.

 

[kgruber]

Did they overhaul the oil pump and the accessory gears?

 

[SixPapaCharlie]

Did they overhaul the oil pump and the accessory gears?

Those are the only notes.
I saw it and was wondering one would do a bottom end and then a top end versus doing a major overhaul. I figured based on that it might not be the same.

 

[N747JB]

I think from the book definition, no. From a practical standpoint, probably so. After all, they did go through the entire engine within about 50 hours.

That said, I'd worry that the owner was trying to cut corners when s/he only did the bottom end, and that a certain element of "frugality" went into the rebuild. With that in mind, I'd need to see all of the paperwork - dimensions and the like, to make sure they didn't <effectively> tear an engine apart and rebuild it to "well worn" condition.

I would have the same concerns, was it two months between repairs or two years, maybe it sat for a while and the cylinders rusted?? But, I would be skeptical for sure.

 

[airdale]

I would ask to see the shop tickets, then consult someone you trust for a review of the tickets and comments on the reputation of the shop.

More generally, doing the work like this would make me suspect that the owner was short of money and only did maintenance when he had to. So what other maintenance has had corners cut or has been deferred?

Another thing: How old is the work? If years old, be sure to have a jug pulled and a borescope look for corrosion, especially lifters and cam lobes.

 

[fiveoboy01]

Technically no.

I wouldn't get near it.

 

[GRG55]

Those are the only notes.
I saw it and was wondering one would do a bottom end and then a top end versus doing a major overhaul. I figured based on that it might not be the same.

The only time I have seen engines where the bottom end was redone without doing the cylinders was because the engine was well before TBO but metal was detected in the oil.

In each case it was because of an "economical" previous overhaul and parts such as the camshaft and accessory drive gears were reinstalled instead of being replaced. If the hardened surfaces on these components subsequently spalls or wears the part will start shedding metal quickly. That left the unfortunate owner with the prospect of another complete overhaul well before TBO, or doing the less expensive bottom end only to deal with the metal.

 

[GRG55]

I would have the same concerns, was it two months between repairs or two years, maybe it sat for a while and the cylinders rusted?? But, I would be skeptical for sure.

If it sat and the cylinders rusted then there's a good chance other things rusted as well, such as camshaft if it's a Lycoming.

 

[frfly172]

No,looks like someone wanted to save money,and it didn't work,would want to do a close review of the logs.

 

[alfadog]

139 SMOH (Bottom End Only!)
81 Since Top Overhaul

No, assuming this is a Lycoming, there are a lot of parts in the top end that must be replaced if the engine is to be considered overhauled according to Lycoming Service Bulletin 240. (Attached)

 

[fiveoboy01]

No, assuming this is a Lycoming, there are a lot of parts in the top end that must be replaced if the engine is to be considered overhauled according to Lycoming Service Bulletin 240. (Attached)

This was my understanding as well when talking with my engine builder through my overhaul. I considered overhauling the cylinders(Titan) that were on it since they had about 350 hours on them, but decided to just go with new Lycoming cylinders as the used cylinders would require quite a few new parts.