Top overhaul on high time engine question

T

Todd82

Line Up and Wait
Joined
Mar 19, 2017
Messages
984
Location
OH
Display Name
Display name:
Todd
Question for the community... And yes I know get a proper prebuy, but I'm asking if it's even worth investing in that or just walk away.

'62 Cherokee 160 that was long ago upgraded to 180hp. A couple years / 100 hours ago someone top overhauled the cylinders, etc. It's still a 20+ year old 2000hr engine though. Oil analysis comes back clean, supposedly, but that was the one piece of paperwork he didn't have in the plane that day. Otherwise you can see the pride of ownership involved, hangared, clean; but poor guy is losing his mobility and can't climb on the wing anymore.

I know it's crystal ball stuff, but did topping that engine actually buy any time and is it worth anything or should I just plan/budget on immediate OH? Is there any way to inspect the bottom end without basically overhauling it anyways?

Where I'm at I'm going to need ADSB immediately, and it's such a sparse panel (only one old nav/comm) that my "Year 1 budget" needs to be panel. I don't really dig operating in Class C with just one old comm. If this is going to be purchase + panel + engine all at once, I'll just walk away as if that engine has no life left it's not a good deal.
 
So long as there is no corrosion that bottom end probably has a lot of life left if it’s a first run to get that 2000 hours.

No one with integrity will tell you not to worry about the motor but if you want a clean slate to make it yours then it sounds like a solid airplane. Just don’t over pay. I would value the engine at core only. If it is first run I think the top bought some time.
 
I bought a Bonanza over TBO and used my year one budget for going through everything (alternator, gear motor, ELT, exhaust, spark plugs, tires, etc...) and even a full panel redo; I crossed my fingers the engine would cooperate, and so far it has. I think I'd actually feel pretty good about a fairly recent top, but I think you're right when you mention "crystal ball stuff" too. As long as the plane is priced appropriately, I feel like you're getting free-time on the engine, at least that's how I looked at it.
 
Look at the oil analysis and (guessing there's a few of them) look for a trend. Hot idle oil pressure tells a lot about the condition of the engine bearings and clearances (wear).

What is the oil consumption rate?

Get a good look into the oil filter and screens (if applicable) and see if any metals are found.

What do the engine logs show for maintenance? Has it been a healthy engine or has it been a sickly child all along?

Does the plane fly often or has it been sitting for any length of time? Regularly run engines seem to fair much better over the long run.

From an article by Mike Busch:

While there’s no question that the highest risk of catastrophic failure occurs in the first few hundred hours after engine assembly, I have yet to find any evidence that the risk rises significantly as the engine is continued in operation beyond the manufacturer’s recommended TBO. In particular, I’ve never seen a scintilla of evidence suggesting that an engine at TBO+500 is any more likely to suffer a catastrophic engine failure than one at TBO-500.
Click to expand...

https://www.avweb.com/ownership/the-savvy-aviator-45-how-risky-is-going-past-tbo/
 
One needs to be prepared for a major overhaul no matter how few (or how many) hours are on an engine. Ain't no guarantee that it will make it to 2000 (or 1000 (or 500 (or 250))) hours. On the other hand, if it's pushing "TBO" one would factor that into the price of the airplane even though it may run for another 1000 hours...
 
I would give no value to the top overhaul, would be suspicious how well the owner maintained the plane since the plane was close to TBO and he chose to top. Very few would top a run out engine(even Mike Busch would replace a cylinder that was beyond TBO before he would TOP all the cylinders). If I have a bad cylinder, I would replace, but if all of them were bad I would major rather than TOP all the cylinders.
 
I'm getting the idea that the Top wasn't worth the space it takes in the logbook, and therefore it needs treated like a run out engine. In that case I think I'll just walk away, because as it sits it's not worth nearly what is being asked.

Thanks everyone.
 
Just wanted to say you're a smart man to not become emotionally attached to a plane. Someone I was asking to prebuy for me once told me about a fella who bought a beater 152 and then was investing 50k in repairs before engine, interior or panel work...
 
wheaties said:
Just wanted to say you're a smart man to not become emotionally attached to a plane. Someone I was asking to prebuy for me once told me about a fella who bought a beater 152 and then was investing 50k in repairs before engine, interior or panel work...
Click to expand...
Honestly I'm the other way. Too hesitant to pull the trigger and sign the check.
 
That is a very reliable engine if flown regularly. If it is left sitting for a duration of time internal corrosion becomes an issue. At a minimum I would pull a cylinder an use a bore-scope to inspect the cam lobes and lifters for corrosion or pitting.
 
You must log in or register to reply here.
Back
Top