First time buyer, needing advice!

[jswantekdds]

Hello everyone! I am happy to say that I recently made an offer and had a prebuy inspection on a Cessna 172H (Continental 0-300 engine) that I am interested in buying. It does only have 600 hours SMOH, however the major concern is that it was last overhauled in 1983. The engine cylinder compressions are all very good, all in the 70's. The plane has been flown on a regular basis, just very little, obviously... (it hasn't been sitting around for years without being flown according to the logbooks). My concern is: if I buy this plane, am I going to be overhauling this engine soon because its been 30 years since its last major overhaul??

Thanks to anyone who can lend some advice!!

~Jason

 

[gismo]

Hello everyone! I am happy to say that I recently made an offer and had a prebuy inspection on a Cessna 172H (Continental 0-300 engine) that I am interested in buying. It does only have 600 hours SMOH, however the major concern is that it was last overhauled in 1983. The engine cylinder compressions are all very good, all in the 70's. The plane has been flown on a regular basis, just very little, obviously... (it hasn't been sitting around for years without being flown according to the logbooks). My concern is: if I buy this plane, am I going to be overhauling this engine soon because its been 30 years since its last major overhaul??

Thanks to anyone who can lend some advice!!

~Jason

I'd either find a way to inspect the cylinder wall and especially the cam lobe condition or expect (and budget for) some expensive engine work in the near future.

 

[stratobee]

It's impossible to tell. But whenever an engine hasn't flown much, and 600hrs in 30 years is nothing - then the chance of corrosion and other problems go up considerably. Good compressions don't really tell you that much.

Has there been any oil analysis done by previous owner? That can give a hint of what kind of metals are present and the condition of components. Does it burn oil? Does it spit it out through valves, breather tubes, leak it etc or does it burn it? Can you do a borescope inspection? That will most likely tell you the condition of the walls, valves and piston. Does the oil filter contain metals? Ferrous or non-ferrous?

I'd do these inspections first hand, and it looks OK, then it probably will give some good flying. Another thing you can do is if it doesn't make metal or don't suspect there's something wrong with the bottom end, then do a top overhaul. It's pretty cheap to do and will give you piece of mind. Very rarely is the bottom end shot, however, the cams and the lifters can be bad so if that's the case, then a top end might not be the best way forward.

 

[jswantekdds]

Thank you much for the advice!!

 

[Tom-D]

Hello everyone! I am happy to say that I recently made an offer and had a prebuy inspection on a Cessna 172H (Continental 0-300 engine) that I am interested in buying. It does only have 600 hours SMOH, however the major concern is that it was last overhauled in 1983. The engine cylinder compressions are all very good, all in the 70's. The plane has been flown on a regular basis, just very little, obviously... (it hasn't been sitting around for years without being flown according to the logbooks). My concern is: if I buy this plane, am I going to be overhauling this engine soon because its been 30 years since its last major overhaul??

Thanks to anyone who can lend some advice!!

~Jason

You will know within 5 hors flying if the cylinders healed themselves, if so run it, until you have symptoms of an impending failure.
low oil pressure
low power
low compression
high oil consumption
metal in the oil.

don't overhaul it until you have reason to

Lots of Lycoming folks do not believe the 0-300 doesn't have the problems with setting around that the Lycoming engines do.

I know of one 0-300 that sat at Hoquiam Wa (on the coast) for 40 years unattended, the new owner drained and flushed the oil, ran it 5 minutes, drained the oil thru a white rag, found nothing, put the oil back in it, ran it for 1 hour at full power, drained and flushed the engine, filled it with W 100 and flew it to Florida, the cylinders on the out side were rusty the mags were white powder all the hoses were cracked but it ran like a new one.

 

[somorris]

Enjoy your new airplane!

 

[frfly172]

Do an oil analysis and get the history of the frequency of oil changes.review the logs for previous engine work.the 0300 does cost a little more to overhaul as it is a six cylinder.had a 172 with the 0300 great little plane enjoy I t.

 

[Theboys]

I have owned two 172,s with similar conditions. Both of them came out fine. Both are still flying with no engine work needing done. One has 350 hours since I bought with no work other than a few gaskets here and there. I did change oil at 25 hour intervals and still do. The other one has about 30 hours since buying and it seems to run even better. I'm thinking its a crap shoot. Might last for years and might not. Same holds true though for newly gone thru though.

 

[Tony_Scarpelli]

You have better than a 95% chance that there will not be very high unexpected expenses on the engine. For this reason I would not worry about it too much.

I put 4 oz of Marvel Mystery oil in my Cherokee for years when I had it, also burned mogas (had a mogas stc) and the engine just kept on ticking.

Small engines like the lower octane of mogas. MMO helps keep the valves clean or unsticking among other things. I bought my Cherokee with 2000 hrs on the engine and ran it until it had nearly 3000hrs 1000 hrs past tbo. Guy who sold it to me used MMO otherwise I have never heard of mmo. But I figured if it worked for him why change it.

As others have stated, I recommend you begin an oil change/oil analysis routine so you can start a baseline of metals in the oil. Then watch this trend over the years and hours. This is one of the best diagnostic methods to avoid catastrophic failure. You can buy the oil analysis kits for $11 ea. Id consider change the oil the first time at 10 hrs to get the old rust/corrosian build up out of the oil after that go to 50 hrs intervals. I do not think you need to do 25 hrs. I did 100 hr changes on my Cherokee which lasted through 3000 hrs. Most people just like to spend extra money on oil I guess. Good Luck