Engine Transplant

[brentdur]

I was looking over my engine logs and a few decades ago there's a line that runs something like:

- "The engine removed from Mooney M20F N<lists reg numbers> for overhaul"

Which is interesting because my plane is an M20E. It's somewhat explained by the following line:

- "Installed this engine in M20E N<my reg numbers>. Motor overhauled ... <goes on to describe the overhaul"

 

I was curious if anyone had an possible reasoning as to what would cause an engine to be removed from one plane for an overhaul, overhauled, and then inserted into another plane?

Edited April 21, 2021 by brentdur

[mschmuff]

Could be a number of things.  The one that comes to mind would be something happened to the F.  Damaged somehow on the ground while not running.  It was parted out but since no sudden stoppage the engine would be fine.

[hmasing]

My Mooney was purchased with a transplanted engine, fwiw. *shrug* not a huge deal.

[cferr59]

I suppose this questions stems from the fact that it would make more sense to overhaul the existing engine rather than overhaul and swap in an engine from another aircraft.  Why this was done is anyone's guess?  Here are a few speculative reasons:

1.)  The existing engine had an issue that would cost extra at overhaul like a cracked case, crankshaft AD, other AD, etc.
2.)  The existing engine had a lot more TTSN so it was expected that the swapped overhaul would need less work.
3.)  The existing engine was at TBO, but nothing was wrong.  The owner decided he/she wanted an overhaul anyway, but wanted less downtime.  They found a similar engine, had it overhauled while still flying the E, then swapped it.

[DXB]

When I think I'm getting close to needing an overhaul, I'd like to find a core, overhaul it, install it later to limit downtime, and then extract the value of my removed core somehow.  That assumes I'll be lucky enough not to be hit by a sudden unexpected need for overhaul.   I'd be curious to hear logistical and cost considerations from folks who've gone this route.  

Edited April 22, 2021 by DXB

[A64Pilot]

Just now, DXB said:

When I think I'm getting close to needing an overhaul, I'd like to find a core, overhaul it, install it later to limit downtime, and then extract the value of my removed core somehow.  That assumes I'll be lucky enough not to suddenly be hit by a sudden unexpected need for overhaul.   I'd be curious to hear logistical and cost considerations from folks who've gone this route.  

What many will do is order a factory overhaul and when it arrives, swap out and send the old engine in for the core charge of course.

‘Accomplishes the same thing, but may cost more, but is a lot more simple, plus factory zero time motors make a airplane easier to sell or bring a higher price than most field overhauls

[carusoam]

Brent,

There are dozens of reasons for engines to come and go...

Very few stay with the plane they were born with...

The important thing is that the engine you have is the right one for your plane...

Where that engine came from... is nice to know, but I don’t think there was a requirement for that...  the note probably explains why the engine logs changed the N-number in the middle of them... 

This is why the engine has its own log books...

PP thoughts only, not a mechanic...

Best regards,

-a-

[DXB]

15 hours ago, A64Pilot said:

What many will do is order a factory overhaul and when it arrives, swap out and send the old engine in for the core charge of course.

‘Accomplishes the same thing, but may cost more, but is a lot more simple, plus factory zero time motors make a airplane easier to sell or bring a higher price than most field overhauls

Unfortunately my engine is original to my '68 plane and hasn't been been back to the Lycoming factory since then - which excludes exchanging for an overhauled one, so I'd swallow the price for a rebuilt one - about 5k more. 

Language from lycoming service letter L250A: "Exchange engine cores that last left the Lycoming Engines factory 36 or more years ago in new, rebuilt, or overhauled condition can only be used towards the purchase of a Rebuilt or New exchange engine."

I'd kinda like to pick up a core somewhere, have it overhauled by Penn Yann or similarly reputable shop, and then have it sitting pickled in a crate that can serve as my living room coffee table until I need it.

[1964-M20E]

I'm in the process of taking an IO-360A1A from an E and putting it on my F.  So they go both ways. 

Yes having a spare engine to overhaul prior to swap is nice and not necessarily cheaper.

[brentdur]

To be clear, I’m not at all concerned by the engine, it’s been a while since the switch so if it something catastrophic was gonna happen it would’ve already happened. Was just curious about the history, thanks for addressing that! 
 

Looked up the other plane too and it’s still flying, and apparently still has the Rajay Turbocharger that I have the logbook entry for!

Edited April 22, 2021 by brentdur

[PT20J]

Lots of mysteries in old logbooks . The regs say that you have to log what was done, but not why.

[1964-M20E]

On 4/22/2021 at 10:41 PM, PT20J said:

Lots of mysteries in old logbooks . The regs say that you have to log what was done, but not why.

if it's not written down it did not happen.  The regs also only require 1 year of records except for STC items.