Major Overhaul ?

[kruiser]

Ok..... looking at a 172 and it advertises 235 SMOH..... so I asked when the major was done.... his reply 1974 !!!! my first thought was NO WAY. and he never mention anything about proper storage etc. With that little bit of hours any chance of it being still good. it is flying now, and what if I got the oil analyzed?

Part 2 what about these major overhauls that are done by your local mechanic vs one done at a major overhaul shop?

 

[JHW]

lycoming or continental? assuming lycoming, pop some rocker covers and measure valve lift. Look for metal in the oil. If it's not making metal and the cam is still making lift then it's an engine you can think about flying. As for money, that's up to you. Offer what you want to pay. Plenty of 172's to choose from.

regarding where the overhaul is done, keep in mind that the important bits (the case/crank/cam machining and the cylinders) are subbed out to a handful of big shope no metter who builds the engine. I overhauled my last lycoming engines in my garage.

 

[Henning]

It most certainly is calendared out lol. Does it need an Overhaul? Probably not. It likely will need seals replaced.

 

[Pedals2Paddles]

If you were a hunk of metal, sitting around, not moving, collecting rain water, salt, dirt, insects, and bird crap, what condition would you be in?

 

[Henning]

If you were a hunk of metal, sitting around, not moving, collecting rain water, salt, dirt, insects, and bird crap, what condition would you be in?

Some planes sit in a hangar in the desert too. Everything is situational. If it has had 50 hrs flown on it in the last year and doesn't have problems, it's not likely to be in too bad of shape.

 

[NoHeat]

Ok..... looking at a 172 and it advertises 235 SMOH..... so I asked when the major was done.... his reply 1974 !!!! my first thought was NO WAY. and he never mention anything about proper storage etc. With that little bit of hours any chance of it being still good. it is flying now, and what if I got the oil analyzed?

Part 2 what about these major overhauls that are done by your local mechanic vs one done at a major overhaul shop?

40 years ago.

What amazes me is that engines haven't changed since then. And so one can actually contemplate flying that plane.

 

[Henning]

40 years ago.

What amazes me is that engines haven't changed since then. And so one can actually contemplate flying that plane.

Yeah, as long as it's in good condition. Probably need to replace the front crank seal (they get dry and then the pressure blows through and out the vent taking a bunch of oil with it), I had them change both on the 310 at annual, total of $600 to do both, parts and labor, not a huge deal. There's probably going to be minor carburetor issues, not huge, dry rotted induction hoses will probably need tending to. The wild card is the cam, and if it's run 50hrs and not making metal on oil analysis or in the filter. That cam may be old enough I think it predates Lycoming's soft cam issue.

Anyway, it's calendar expired on TBO so it prices as a runout. If the engine passes inspection, it has the potential to provide a very good value.

 

[flyingron]

274 hours in 35 years? Yeah you're going to have problems. I suspect every piece of rubber on that plane is suspect and I'd be expecting corrosion. I thought I was being risky buying my Navion that only had 200 hours on a 15 year old overhaul.

 

[Henning]

274 hours in 35 years? Yeah you're going to have problems. I suspect every piece of rubber on that plane is suspect and I'd be expecting corrosion. I thought I was being risky buying my Navion that only had 200 hours on a 15 year old overhaul.

If it was stored in stable conditions, the risk is not much greater.

 

[Pedals2Paddles]

I would like to think if it spent the last 35 years collecting dust in a hangar, someone would mention that detail. It's kind of a major selling point. Somehow I picture this thing as the proverbial neglected plane tied down on the grass at the end of the transient line that nobody knows anything about forever.

 

[Henning]

I would like to think if it spent the last 35 years collecting dust in a hangar, someone would mention that detail. It's kind of a major selling point. Somehow I picture this thing as the proverbial neglected plane tied down on the grass at the end of the transient line that nobody knows anything about forever.

Those planes don't usually make it back, especially not in today's market where you can buy a plane for less than the cost of doing the interior. Hangar queens do make it back more frequently, so my assumption would be as hangared. Either way, an inspection will tell one what the reality is.

 

[weirdjim]

If you were a hunk of metal, sitting around, not moving, collecting rain water, salt, dirt, insects, and bird crap, what condition would you be in?

Better than I am right now after collecting fats, monosodium glutamates, polysorbate 80s, and barrels of ethyl alcohol for 70 years

Jim

 

[Anthony]

I would value this plane as the engine being run out, and needing a new engine or major overhaul.

 

[flyingron]

If it was stored in stable conditions, the risk is not much greater.

The rubber stuff was shot (the gopher engine has a pressure carb which needed to be overhauled). No real signs of corrosion (the plane lived it's entire life in the Chicago environs). Admittedly the thing subsequently died due to high heat I suspect do to crappy baffling in the downdraft cooling conversion done previously to try to IMPROVE the heat issues. There was a second oil cooler on the accessory case.

Another thing to watch out for is the accessories. If the engine hasn't been overhauled, the accessories probably haven't been touched either. I had carb, alternator, mag, etc... issues before I got around to the engine being a problem.

 

[Henning]

The rubber stuff was shot (the gopher engine has a pressure carb which needed to be overhauled). No real signs of corrosion (the plane lived it's entire life in the Chicago environs). Admittedly the thing subsequently died due to high heat I suspect do to crappy baffling in the downdraft cooling conversion done previously to try to IMPROVE the heat issues. There was a second oil cooler on the accessory case.

Another thing to watch out for is the accessories. If the engine hasn't been overhauled, the accessories probably haven't been touched either. I had carb, alternator, mag, etc... issues before I got around to the engine being a problem.

Exactly, after 15 years pretty much all the 'age' damage is done, another 20 years doesn't matter if you have to change out all the rubber parts anyway. Even corrosion is somewhat self limiting once the first layer forms.

 

[flyingron]

Yep, I was referring to anything over 12 years as suspect (maybe shorter).