Old Continental engine - supportable?

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ateamer

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ateamer
I’m looking at a square tail 172 to maybe be my next plane. It has an O-300A, 1900 since major, 5000 total time on the engine. Compressions, for what it’s worth, are in the mid 70s. I expect it’s going to need an overhaul sooner than later. When that happens, if the crankshaft, camshaft, or case are rejected, what will I be in for? Are they readily obtainable, or will the plane be sitting for months and months, or will those parts cost way more than for a more current engine like a 320 or 360?

I’m looking to fly, not to have a project. Is this particular engine likely to make for a longer and more costly overhaul?
 
You'll be sitting for months and months waiting for an O-360.
Parts for the O-300 are obtainable. Press on.
 
O300 are smoother so I am told. Lots of them flying still.
 
You can't get a new crank from Continetial for an O-200 at present so you have no chance for an O-300.

If it was me I'd get flying the thing and keep a lookout for a suitable O-360 core.
 
You can't get a new crank, but you can certainly get a serviceable one that can be inspected and ground.
Is there even an STC to put an O-320 on an early C172?
 
Bathman said:
You can't get a new crank from Continetial for an O-200 at present so you have no chance for an O-300.

If it was me I'd get flying the thing and keep a lookout for a suitable O-360 core.
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Can't get a crank for the big Continentals either. 12 months lead times for factory remans too.
 
aftCG said:
You'll be sitting for months and months waiting for an O-360.
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Why? Unless the cylinders are oversized, parts should be easily sourced with the garden variety O-320 and 360’s.
 
The O-300 is an easy starting, smooth running engine. I really like mine. A climb rate of 500 FPM is about all I get in my C-170.

I did a certified overhaul on my O-300 a few years ago. My crank had to be replaced. We found one in great condition that they said had 1-2 more grinds left on it. $9500. Also found one with minimum serviceability for $7000.

The oil pan is magnesium and tend to corrode towards the rear from water sitting at bottom (C-170 taildragger). Mine had an unapproved repair done that needed to be redone. $1500 to spray weld it.

Plane was down for about 5-6months. Airworx did the work for me. It’s been running great for about 150 hrs now. I don’t like that it drips 5-10 drips of oil after a flight. Some say these engines just seep oil a bit. Others track down the leaks and are able to keep it clean.

All in with annual was around $40k. I have heard reports that putting on a 180 hp engine is closer to $90k…its a firewall forward endeavor. But that power is needed for high elevations.
 
Does the 180 stc reduce, keep the same or increase useful?
 
Overhauls are definitely not cheap. I have an O-360-A4A on my Cherokee. Pre-buy found no major issues at all. That engine ran like a top and didn't use a drop of oil. At about 1200 SMOH and at the annual inspection, a cracked cylinder led to the discovery of a camshaft crack and subsequent overhaul. Lycon quoted $25k basic overhaul price, up to $33k for the fancy port/polish/STC stuff they do to increase horsepower. After teardown, turned out that the crankshaft wasn't serviceable either. I ended up with new, since the price differential between new and used was only $3K. When all was said and done, that perfectly purring engine has cost 55 AMUs to get back into service, on a plane that cost $74k.

Engines are a total crapshoot. I'm not sure it's possible to guarantee that any engine you buy isn't going to ground you at some point. For my money, run that O-300 until it tells you itself that an overhaul is necessary, and save up your pennies in the meantime for an expensive overhaul. In a perfect world, the eventual overhaul won't cost that much and you'll have built up a nice maintenance fund to put aside!
 
RyanB said:
Why? Unless the cylinders are oversized, parts should be easily sourced with the garden variety O-320 and 360’s.
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Ask the engine builders. At our part 135 operation we have two C172Ms with the O-360 conversion. One idiot pilot whacked some taxi way lights requiring a teardown. We shopped the entire country for the engine and were told 3-6 months.
We almost bought a beater C172 just to get the engine, but found a 160hp and installed it. When it times out in a year we (now) have an O-360 to replace it.
More data clutter, 3-6 months is what we're currently being quoted for TCM IO-520s.
 
aftCG said:
You can't get a new crank, but you can certainly get a serviceable one that can be inspected and ground.
Is there even an STC to put an O-320 on an early C172?
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Delair in Porterville California. KPTV.
They do a conversion kit, optional cs prop.
172 with 182 performance
 
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