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Engines that have sat (looking at a used engine)

rmartingt

Well Known Member
I have a possible lead on a low-time engine that was "flown regularly until the end of 2014" and then I think has only really flown once or twice since then (when the current owner bought the airplane it's attached to back in December and flew it home). It has since sat again for a few months in a dry climate. Owner says the compressions were "high 70s" during his pre-buy.

Are there any "gotchas" I should be looking for? I know that sitting isn't good for an engine and I've been told that the cylinder walls and camshaft are the places to look for corrosion. Trying to figure out if it's worth a weekend trip to go look at in person or not.
 
I have a possible lead on a low-time engine that was "flown regularly until the end of 2014" and then I think has only really flown once or twice since then (when the current owner bought the airplane it's attached to back in December and flew it home). It has since sat again for a few months in a dry climate. Owner says the compressions were "high 70s" during his pre-buy.

Are there any "gotchas" I should be looking for? I know that sitting isn't good for an engine and I've been told that the cylinder walls and camshaft are the places to look for corrosion. Trying to figure out if it's worth a weekend trip to go look at in person or not.

You never know till you look.

I purchased an engine core in Southern California. It sat in the hangar where I purchased it, then in my hangar for several years. I then moved it to Pennsylvania where it sat another 2 or 3 years (in a moist environment) for a total time of 7-years since last run. When I tore the engine apart last year, the cylinder walls did not appear rusty but when wiped with a white paper towel, it got a brown residue off the cylinder walls. (Possible rust that cleaned off just by wiping with a paper towel.) They were original Lycoming cylinders. The cam and internal parts all looked good meaning no visible rust or pits. NDT and inspection will determine if they can be reused. The two most expensive parts on a used engine is the crankshaft and crankcase.

In my humble opinion, it the engine was run regularly for the first 100-hours, there should be some varnish (brown residue) form on the steel parts that do not come in contact with other parts that help protect it from rust.

If the cylinder barrel is chrome or the ECI nickel finish, they will not have rust on them. The BLUE paint on the cylinder head fins are an indication that it is an Original Lycoming nitrite cylinder. The Lycoming cylinders on the 7-year sitting engine that I tore apart did NOT have rust pits.

Lycoming does recommend a 12-year overhaul on their piston engines regardless of times. Part 91 operators to not need to follow the manufacturer's recommendation.
 
If the price is reasonable, I'd say it's worth a trip, especially considering it's in a dry climate.

Unless you buy new, I found it almost impossible to find that unicorn of a used engine that has been cared for properly, run every week, etc. It just doesn't happen much in GA. I was lucky enough to find a 700 hour O-320 with new cylinders, from a fellow VAF'er who was upgrading to an O-360. He had all logs, oil analysis, etc. It has still had some inactive periods since last overhaul, but has been flawless besides needing a carb overhaul, for the last 150ish hours since I have installed it, and oil analysis and inspection continues to be excellent. It also sat for a year after I bought it before flying, and I made up a dehumidifier system to help keep it dry inside.

As long as the price is consistent with the risk, I'd take a look.

Chris
 
It's actually the whole aircraft that's for sale, though it's not quite flyable right now. I could use the prop, engine, and avionics. Would be parting out some components to fit the SDS system. If it works out I could save $10-15k or more. Would hate to part out a nearly flyable airplane but...
 
Risk

There is always a risk of corrosion, as you say cylinders,camshaft and also the crank. My engine as sat for a long time inhibited, I checked the crankshaft by removing the plug and for corrosion in there. Fortunately it was salvageable but obviously required a full strip.


I am currently dealing with a 7 that was sat and has corrosion in the bores.

If the price is right it's worth the risk, but bid on the basis that you will find a problem..
 
I bought an O-360 from Beegles. It had sat for close to 20 years without running - either on the front of a Beechcraft wing, or on a shelf, I don't know which. The exhaust ports were cracked, but I was counting on replacing all four cylinders and paid accordingly. Other than that the bores were fine, all the internals were fine, no rust, no pitting, it was a usable core. I've heard some horror stories so maybe I just got lucky, I don't know.
 
I bought an O-360 from Beegles. It had sat for close to 20 years without running - either on the front of a Beechcraft wing, or on a shelf, I don't know which. The exhaust ports were cracked, but I was counting on replacing all four cylinders and paid accordingly. Other than that the bores were fine, all the internals were fine, no rust, no pitting, it was a usable core. I've heard some horror stories so maybe I just got lucky, I don't know.

Many factors involved. I also bought a bottom end that sat for 20 years. Cam was red tagged from pitting and crank had corrossion as well, but was able to be machined 30 under. Difference was, the oil from the final run was milky colored (had a lot of moisture in it). The oil holds the moisture in suspension and lets it leach into the metal parts it is touching over time.

Larry
 
I bought a mid time "runner" from an unnamed salvage yard that had sat for 5 years before my purchase. Upon disassembly, I found the cam and lifters were totally trashed. This was sort of to be expected. I also found a scored crank that had already been ground to minimum spec, and 2 cylinders with broken rings. I opted for a total overhaul and ended up with a lot of expensive hangar decorations.

If I had to buy another engine I would take more interested in regular use, service records and the logbooks than just the TT #

my .02c

Caleb
 
I'd say it depends on the price. Used engines are definitely a bit of a gamble, but if you get it for a price you are happy with then go for it. I think I paid around $7000 Canadian for an engine with 450hrs since a brand new cam, treated crank, new main bearings, OVH cylinders, and about 20 hours on a new carb, mags and starter. I'm going to fly it keeping a close eye on everything. If I get away with it great, but even if it requires a new cam and lifters I would still be pretty happy with the total cost of what is a fairly low time engine. Plus I would get to take an engine apart!
 
I found the aforementioned unicorn on Barnstormers in late 2015. The engine was overhauled (zero time) in Aug 2014, then flew almost 1100 hours in a year (flight school) before a wind storm destroyed the plane. It sat a few months but was in the Phoenix, AZ area.

I had to replace a damaged cylinder, which provided an opportunity to peak inside. Desiccant plugs were installed and reloaded for the next year while I finished the build.

Paid 8k + 500 shipping. Then spent more on a P-Mag, FI and Vetterman exhaust.
 
Thanks for all the input, everyone. I've decided to pass on the one project I was looking at--the history of the engine didn't give me warm fuzzies, and an overhaul would have eaten up every bit of savings I got from the deal.

I've talked to a local A&P with a lot of overhaul experience, and he's willing to work with me if I find an engine. He's estimating a ballpark cost of $14k, including new cylinders, cam, and lifters, and required NDT/machining, assuming the crank and case are good. Is this reasonable, or an extreme? Note, I'd be selling mags, fuel system, etc. to go SDS EFI.

I've also been looking at maybe picking up an old airframe for the engine, prop, and usable avionics. And in true engineer fashion, I've worked out a spreadsheet comparing various options and estimates for new engines, and the estimates for a few rebuild scenarios. The results are interesting.
 
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