I'm looking at an airplane that had a field overhaul ten years ago by Quackenbush Aviation up in Seattle. (He's since retired)

In the decade since, it's flown maybe 20 hours. Compressions are good. Oil consumption appears to be good, but I don't see how the rings could have even sat yet.

TCM IO-470H

Obviously a very thorough borescope and engine oil analysis is needed during the pre-purchase inspection. I have no O-470 experience besides flying behind them. What's the hive wisdom for being able to mitigate the risk associated with purchasing an airplane whose powerplant has been through this scenario?

Any thoughts would be much appreciated.

Check the lifters too.

Hi Dan-

The best way to mitigate the risk of an engine that has set for ten years is to be sure that you do not pay too much for it. If everything that you can see with borescope, etc. looks good, I might consider valuing the engine at 20-25% of a fresh overhaul. I would be interested in hearing the thoughts of others.

Regards,

Bob

Count on doing a top overhaul after flying for a bit.

Much less likely if it has chrome cylinders. If cermichrome plan on it regardless. Continental engines are not as prone to cam and follower corrosion as Lycomings are due to the cam at bottom but it still happens.

Much less likely if it has chrome cylinders. If cermichrome plan on it regardless. Continental engines are not as prone to cam and follower corrosion as Lycomings are due to the cam at bottom but it still happens.

It certainly can happen but not always. I recently parted out a pair of TIO540N2BDs that were sitting on a C310 for over 25 years in an uninsulated T Hangar not far from the coast in Va. All 12 steel cylinders, all lifters, both cams and cranks, all were rods and gears were good.

Thanks, Guys!

As much as I like this particular airplane, I don't think I'm going to get the owner to come down to a price where I'm not assuming the risk on this engine.

I might get lucky, but I'm not willing to gamble the cost of an IO-470 overhaul out of my pocket, when I can be patient and eventually get that risk baked into the cost of the airplane and the loan itself.

I realize that nothing is 100%, but a regularly flown airplane with a couple of hundred hours of oil analysis is much, much more likely to go to TBO.

IMO every O470 will get some top work done before TBO.

I feel like i would be worried about the rest of the plane. Unless it's a very simple aircraft the systems could end up costing as much as the engines if not more.

I know nothing about hangar queens but I know when my planes sit for weeks they make me pay in some way. I can't imagine all the ways a plane that has sit for 10 year could make you pay.

Mike

A friend and I recently rolled the dice on a Stearman that hadn't flown in 12 years. Fortunately it was stored inside the entire time. I guess it's flown about 3 or 4 hours since we bought it and we've had some issues. The only engine problem so far, and the mechanics are heading to the airport today where we had to park it on Friday, is rough running on the left mag. Hopefully, it's just a plug and they're be able to fly it home this afternoon. I agree with Bob S. If everything else seems reasonable with the plane, you need to buy at a price that can support getting the engine rebuilt or close to it.

Pull every lifter and look at the cam. Then bore scope the jugs. Then don’t pay too much.

So here's another question. My understanding is that you come to an agreement on price prior to the prebuy.

How do you not waste your time and money on a prepurchase inspection when the buyer has an unreasonable emotional belief of what the airplane is versus how they actually treated it?

If I find corrosion that indicates the need for a top end overhaul on an airplane that's pretty close to being priced what it would be if the engine was overhauled last month, how do I create the wiggle room for downward negotiation?

David, Is that Birddog in your avatar powered by an O470?

David, Is that Birddog in your avatar powered by an O470?