Club Homepage Forums Classified Ads Buy & Sell - Everything But Airplanes Thinking about a new engine?

After a lot of deliberation I decided to replace the TBO engine in my 150, and the option I chose might be of interest to other folks in the same boat.

Continental Motors Services offers a "kit engine build" where they build an engine with 100% new parts, then transfer the data plate from your old engine to the new one. The only difference between this and a fully new engine (except price) is that your log shows the total engine time of the old engine -- that is, that the old engine was "overhauled". The price for an O-200-A was $22,398 vs. $27,104 for a new engine or $24,161 for a factory remanufactured engine. The kit build and remanufactured prices are exchange for your old engine; I'm not sure about the new engine price. The kit build price includes a new alternator, magnetos, spin on oil filter, and plugs, but I don't believe mufflers are included.

I assume that having the kit build engine might reduce the resale value of your plane compared to an officially zero time engine, but that's no matter to me since I'm not planning on selling. So I chose the kit build as a less expensive way to get a totally new engine. The old engine is out and on its way to the factory, and I expect the new one in about 3 weeks.

I'll be glad to share my reasons for replacing the engine rather than overhauling it, running it beyond TBO, or buying a different airplane, either via PM or posting if anyone is interested. It certainly isn't the best option for a lot of people but it was for me.

Roy

Roy, this is the same route Mark_vanWyk took a few years ago.
I don't think they called it a "kit engine build" but something like aa all new overhaul.

Interesting move, Roy.

I'm assuming that if you'll have your engine in 3 weeks that the engine is already built, test run and in their existing inventory?

Are you doing other work to other engine compartment items while the engine is out?


Pictures???


It's always fun to watch projects as they unfold.


Jim

Hi Roy,

I'm curious to hear your thoughts on not running beyond TBO. Did you have any symptoms of eminent failure or oil testing?

Jim

I'm assuming that the new engine has been test run and otherwise fully functional. I'll be following the recommended break in procedure to the letter.

The engine mounts and baffling will be replaced, and the firewall cleaned up -- that's the only other engine compartment work I'm planning. My mechanic offered to do some painting but I'm not big on appearances, so opted not to bother with that. While the plane is grounded I'm having the prop reworked and all new Plexiglas put in. I've got some work to do just now but I'll post some pictures shortly.

Roy

No. I actually think my engine was a pretty good candidate for running beyond TBO. Oil analyses were all very good. I replaced the cylinders about 600 hours ago and they're all still 79/80. And the kind of flying I do -- frequent, and quite a few relatively long flights -- should aid longevity. You have to realize, though, that while a bad oil analysis definitely indicates trouble, good ones don't mean that nothing serious is wrong or about to happen.

But replacing the engine now has some advantages, not all unrelated to my age (just turned 70). I've only been licensed for 7 years and want to get in as much flying as I can while I can. By replacing the engine now, I can dictate when the plane will be grounded rather than having it happen at a possibly inconvenient time like the middle of the good flying season -- and/or at an inconvenient place. At my current flying rate of about 200 hours per year, I should get ten years out of a new engine, and think it's fairly likely I'll be finished with flying by then. So stretching the time on the old engine (by what, one or two years max?) probably wouldn't be much benefit except maybe in resale value if the new engine outlives my flying career.

My engine log is incomplete and doesn't show the first 1000 hours or so from the time the plane was new. But it appears that the current engine is the original one, it has 7,000 hours on it, and has been overhauled at least three times (the first at about 1000 hours for unknown reasons). And although it's anecdotal, a local highly respected engine shop remarked that it's seen quite a few major problems (e.g., cracked journals) on over-TBO O-200s. I frequently fly over very rugged terrain and often carry a passenger, so I'd rather err on the side of caution when it comes to maximizing engine reliability. And I'm not the kind of person who lets liability worries dictate his life, but can imagine what prosecution fodder an over-TBO engine would make if a failure were to cause an accident. I can otherwise show that I take very good care of my airplane.

One immediate consideration is that my wife and I are planning to fly from Oregon to Maine and back this summer and I'll feel a little more secure with a new engine (worn in past the infant mortality period) than with one that's past TBO.

So those are my reasons for swapping out the engine now.

I considered selling the plane and getting another, but I've spent so much time and money getting all the little and big problems on this one fixed, getting it set up for IFR, and adding extras (to the ones it already had), that I don't want to start over with another plane. After all is said and done, that route might have been a little less expensive (but not necessarily so) but it would almost surely consume a huge amount of time I'd rather spend flying.

Everybody's situation is different so I'm sure most people will choose different options.

Roy

On most 4-cyl light aircraft engines, by the time the engine has been overhauled 3 or 4 times, there is little if any of the "original" engine remaining. Most engine logbooks should be renamed "log of replaced engine components"..

Roy,

Thanks for a great explanation of your thought process. I totally get it, as I am trying to figure out what to do with our over TBO engine in our 172. Don't know if I can handle an overhaul by myself (my partner is not flying anymore, so probably not interested in splitting that cost).

Maybe we could sell the 172 and I could get back into a 150 by myself this time?...

Jim

I have my own anecdotal, random-sample-of-one, but when my O-200 was disassembled after it's second run to TBO (at least, according to the logs), a cracked crankshaft was found.

I don't know how long the crack was there, or how short before it would have 'notified' me through other means, but there was no indication prior to disassembly.

Sounds like your thought process was very well considered. And you are fortunate to have the means to not let finances color your decision too much.

The zero time, factory rebuilt that Lycoming built for Mighty Mouse was run on a test stand and they sent the detailed test results with the engine showing all of the parameters at numerous power settings......it was quite impressive to review it.

I have to believe Continental ran yours on a test stand as well.

In 2003 I bought a new Continental IO-520BB for my Bonanza and they did not send me the test stand documentation on that engine like Lycoming did.

It's kinda nice to see how the young gal performed on the stand at Lycoming.

Best of luck with your new engine.


Jim