Q: I am looking to buy a 2007 CC18-180 Top Cub with 350 hours TT on the airframe, engine, and prop. The seller said the airplane has not been flown in two years due to health reasons. The annuals have been continued, including the compression tests.
As the prospective buyer I am awaiting the logbooks. I believe the engine is a Lycoming O-360-C4P model. The airplane has been hangared just north of Seattle for its entire life. The seller was going to have it flown to Cubcrafters in Yakima, Washington, for possible inspections to aid in the sale. The sellers A&P is proposing to remove the magneto and inspect for rust, etc.
Would you consider this inspection to be of value towards a possible purchase or, if not, what would you require from the seller if you were the buyer?
John Wells
A: John, when I first read your question, my hair stood on end (and I don’t have much anyway) and I thought this doesn’t look like a good situation.
However, after rereading and rethinking the situation, maybe things aren’t as bad as they might be.
The most important thing I can think of right now is that since the airplane hasn’t been started or flown for two years, don’t do either of these until you follow these suggestions.
My concern is that the engine hasn’t flown in two years, which raises an important question: Was the engine possibly started and run on the ground during that time? If it had been run only on the ground for a short period of time, then I’d be very concerned there would be the possibility of some internal corrosion in the cylinders and the camshaft and tappet body areas.
If the engine hasn’t been run, before anything else, I’d make certain not to rotate the prop. Next, remove all of the spark plugs. A very close inspection of each cylinder with a borescope would be in order and will give you a good picture whether or not there is corrosion in the cylinders.
As you might imagine, if the engine has some corrosion and the engine is started or flown, any corrosion material would then be circulated throughout the entire engine and possibly cause more damage to the engine.
Let’s assume you find indications of corrosion. The next step should be to pick the cylinder showing the most corrosion and remove it for a closer inspection. At the same time, you should inspect the cam and tappet area of the engine for any indication of corrosion in that area.
If there is corrosion in all cylinders, then I’d recommend removing, as an example, the #1 and #4 or #2 and #3 cylinders. This would allow you to get a really good look at the cam and tappets, which are more of a concern than the cylinders.
If you see no indication of corrosion on any of the cam lobes and tappet bodies, then we might be able to save the engine.
Rehoning and removing all of the corrosion from the cylinders can be done. Then reinstall the cylinders using new piston rings and break the engine in using mineral base oil. After that, you should be good to go.
My main concern is the condition of the cam and tappets, so be certain to make a very close inspection in those areas. Should there be corrosion on that area, the only fix would be to overhaul or replace the engine.
If this is the case, you may be able to negotiate a better price, taking into consideration the cost to make the engine healthy again.
I’m sorry, but I just can’t agree with the seller’s A&P proposal of just removing a magneto, because that’s not an area where corrosion would be first to show up.
Bottom line, inspecting the engine now – before the aircraft is flown – is in the best interest of all parties.
Looked at a 1964 Skyhawk at a farm strip SE of UIN some years back. 650 hours TTSN. Last entry in the A&E logbook was in the late 1970’s. Probably not a legal radio in it. I still have no idea what a ‘NarcoHomer’ is…
I calculated it would take $15,000 to comply with all the AD’s and buy a used radio stack for it, not counting what might be wrong inside the Continental. I offered him $10k, he said no way. Heard later somebody gave him $25,000 for it and flew it out of his grass strip. Wow.
I would not even think about buying this airplane unless it was discounted enough for an engine overhaul for all the reasons mentioned. Seen too many people making this mistake and it rarely turns out well.
It would have been prudent to have preserved the engine with preservative oil and dehydrator plugs. There would then be no need to touch the engine until it is returned to service, and this would prevent any rust/ corrosion.
Airplanes that have been sitting . . . hoo, boy, what a minefield!
Ever notice that the “reason” it has been sitting is never something to do with the airplane? Personally, I’d rather buy an airplane that has been flying but now has a known problem, because there’s a pretty good chance that everything else works, remember, the airplane has been flying. Buying an airplane that has been parked for “a while” (months? years?) is a crapshoot, and more than likely YOU are the one who is going to get crap-shooted.
Rust, vermin, corrosion, mildew are all highly destructive to aircraft. Look VERY carefully, don’t believe the seller’s allegations, especially when you hear “I’m just selling it for a friend, I dunno anything about it.” which should be your cue to grip your wallet firmly and run away just as quickly as you can.
Always hangared, fanatical maintenance, never a trainer . . . and the earth is flat, too.
Be careful, lotsa varmints out there, and be extra careful because most of these aircraft are OLD, and when things get old, they don’t work as well as they did when they were new. (This is not limited to aircraft.) The Arabs have a saying – when buying a camel, look at the seller as well as the camel.
I agree with gbigs… It all depends on where the aircraft is located.
We recently acquired a Cessna 172 XP that sat outside on the ramp in Southern Oregon for the last 13 years. The bird nesting in the engine was almost to the top cowl. Dead bugs. But not a mouse carcass anywhere. We cleaned it up, put on some new rubber, rebuild the fuel pump, replaced some lines. Scoped out the cylinders, NO corrosion. Pulled a MAG, NO corrosion, Checked out the internal area of the fuel pump, NO corrosion… Engine started after two blades and runs absolutely smooth…
BUT – I have seen engines from just North of me that were absolute RUST junk.
I would follow Mike Bush’s Savvy Aviator recommendations on bringing an engine back to airworthy status.
No need to immediately tear down the engine, or pull cylinders.!
Awhile back I was considering buying a 1972 7KCAB with an IO-320-E2A. Same scenario, owner had health issues, had not flown it in several years, etc. My buddy (an A&P/IA) suggested we pull off the two cylinders on one side and inspect the cam and tappets. Owner was reluctant to do so and I passed on the sale. I did not want to buy an expensive repair. Good article.
Great article Paul I was wondering, what is the cost of removing a cylinder and overhauling.
Hope to read more of your articles
Bob— retired
A/P
Credentialed Community college instructor, airplane/ aeronautics
Com s/m engine pilot
Depends where the plane has been sitting for the two years largely also. In Florida? or in Vegas. On the ramp or in a hangar. Then worry about water condensing and the oil breaking down and wrecking the crank, bearings, and cylinder walls. Not to mention the dead batteries and possible varmint infestations.
This engine likely has a fixed pitch prop making easy access for a boroscope inspection of the front half of the cam and tappets by removing the front plug in the crankshaft and using the center bore of the crank as access for an articulated boroscope. That will give you access to the front 3 lobes and front 4 tappets. If all is well with them, then the back 4 are likely just as good. A new plug for the crankshaft is less than $5. Inspect the cylinders for corrosion with a boroscope as well. There is absolutely no need to tear this engine down to inspect for corrosion.
“No reason to tear down the engine to inspect for corrosion” huh. Then at least the bare minimum would be to take the precautions Paul mentioned. I made the mistake of not verifying the issues regarding corrosion and after three oil changes I was making metal and had to rebuild the engine.
I run my engine an hour a week making sure l reach 180 degrees oil temp for at least 30 minutes while cycling the prop several times and keeping 2000 rpm and then cutting open oil filter which was very clean.
Do u reccomend anything else ? Thanks Don C.
Don’t just run the engine on the ground. You can’t get to the real temps and RPM that keeps the engine maintained. Ya gotta fly.
Great information. When (and if) I ever seriously consider buying an airplane, I now know one more area to inspect! Thanks