0-320 engine longevity

fudge80

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fudge80
Hi all,

I bought a plane last fall after getting my ppl, it is a 1978 172N with the 0-320 engine in it. The TTAF was only 1750hrs. Time on engine was around 1350.

Person I bought it from was the second owner and he bought it in 1982 and there was an AD or something at the time on the engine that had to be fixed, something regarding the camshaft premature wearing, you guys are probably familiar with it. Anyway it counted as a rebuild and that is why there was a 400 or so hour discrepancy between total time and engine time.

My question is probably obvious to you more experienced flyers but that means the engine was last overhauled around 32-33 years ago, is that a problem to go that long with such little time 50hrs a year average?

The plane has been annualed every year of its life including a month after I bought it, The previous owner who I bought it from simple didn't fly a lot and had cancer a few years that the plane pretty much sat. He has since upgraded to a 182, didn't need two planes and that's why he sold the 172.

EDIT- I should add that the engine runs strong with no noticeable roughness or anything that would lead me to be concerned.
 
Last edited:
Read every thing you can about the Lycoming 0-320-H2AD engine. Look in the FAA data base for the ADs on this engine.
 
50 hrs a year if evenly operated is ok. As Tom alludes to there are a few issues with this engine still. Since you already own the plane, and the engine is running strong, I would just run it to economic failure and replace it with a different -# or more likely I'd choose one of the 180hp conversions.
 
Who cares.

Hows the compression and oil burn and filter cuts?
 
Who cares.

Hows the compression and oil burn and filter cuts?

Exactly, fly 50-100 hours a year and he could get another decade or more out of it. Just keep an eye on it.

I would advise you buy a spare magneto though, sometimes the parts can be hard to find, so it's a good idea to have a spare so you don't end up on the ground for a couple months over a part.
 
Exactly, fly 50-100 hours a year and he could get another decade or more out of it. Just keep an eye on it.

I would advise you buy a spare magneto though, sometimes the parts can be hard to find, so it's a good idea to have a spare so you don't end up on the ground for a couple months over a part.
I can have that mag rebuilt and back on in 3 days.
 
I can have that mag rebuilt and back on in 3 days.

Right now, in 2 years when he needs it the situation may not be the same. That mag has had on and off parts availability issues for years. Finding a coil for one I remember being a big hassle one time.
 
Right now, in 2 years when he needs it the situation may not be the same. That mag has had on and off parts availability issues for years. Finding a coil for one I remember being a big hassle one time.

You may not realize they take the same parts as the other Bendix. Are we worried about rebuilding the SL 20S
 
I have only started it once where it was cold. If its below 20*F I won't fly as I'm in an unheated hangar. The coldest I started it was around 40*F, I had it plugged in for about an hour and a half before starting it.

What would you consider a cold start?
 
Also, the condition of the crank, and the lobes.

You'll never inspect the crank for grooves and such unless you're rebuilding the engine. The best you can really do on a prebuy is track the flange with a dial indicator and do a tap test that will only identify a crack to the first throw.
 
I don't know about this engine in particular but I saw some pretty convincing videos on the topic of running engines past TBO and they advocated paying close attention to the exhaust valves with regular borescope inspection. Seems like sound advice for any aircraft engine.
 
You may not realize they take the same parts as the other Bendix. Are we worried about rebuilding the SL 20S
:rolleyes: Tell us, oh wise one. What parts are the same between Bendix duals and singles?

I'll even get you started.

The brush is the same for all.
One or both of the contacts (depending if SoS) are the same as S200/S1200. The SoS uses one special double contact.
The drive end bearing is the same as S1200.
Slinger is the same as S1200

Coils are different.
Gears are different.
Block is different.
Capacitors are different.
Impulse couplings are different.
Needle bearing is different.

Other than some screws, what else is the same?

As far as getting one overhauled in three days, I'll bet that it was not done per the manual, no matter what the shop signed for. The parts don't exist for a full overhaul.

And some trivia: About 50% of TIO-540-J2BD's are flying with cracked drive couplings. The mag side is a mag part, not an engine part like the S1200's. Most shops won't NDT them because they know they'll fail, they're no longer available, and it isn't a requirement. With it not being an engine part, it doesn't get checked at engine overhaul either.
 
:rolleyes: Tell us, oh wise one. What parts are the same between Bendix duals and singles?

I'll even get you started.

The brush is the same for all.
One or both of the contacts (depending if SoS) are the same as S200/S1200. The SoS uses one special double contact.
The drive end bearing is the same as S1200.
Slinger is the same as S1200

Coils are different.
Gears are different.
Block is different.
Capacitors are different.
Impulse couplings are different.
Needle bearing is different.

Other than some screws, what else is the same?

As far as getting one overhauled in three days, I'll bet that it was not done per the manual, no matter what the shop signed for. The parts don't exist for a full overhaul.

And some trivia: About 50% of TIO-540-J2BD's are flying with cracked drive couplings. The mag side is a mag part, not an engine part like the S1200's. Most shops won't NDT them because they know they'll fail, they're no longer available, and it isn't a requirement. With it not being an engine part, it doesn't get checked at engine overhaul either.

Many of the parts you mentioned are different part numbers by the book, but the will cross to a common part by the subcontractor who makes them.

Lots of the mag parts left on independent shop's shelfs, just because you don't know where they are doesn't mean they aren't.
 
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