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?
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.