Inspecting engine

455 Bravo Uniform

455 Bravo Uniform

Final Approach
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455 Bravo Uniform
There must be a lot of planes on the market where the sellers realized after a year or two that they were not flying much anymore and decided to sell. I'm looking at one now.

Is there any way short of splitting the case that one can determine any deleterious effects of lack of use?

Bore scope in cyls? Any way to inspect the cam and lifters?

Should I walk from a plane that has flown 100hrs since 2014? Basically 20 hrs 2 years ago, and 7 hrs a year ago?

I ask because there was actually an overhaul on this same plane a few years back with about 1,000 hrs on the engine and flown frequently, then sat almost unused for 3 years, then started making metal the year it started flying again.
 
Where is the plane, and what are the compression ratios if you happen to know? And if you are able to believe the seller, how much oil is it consuming? A borescope for corrosion and pitting would also be wise.

You're definitely thinking about the right things as planes often wake up grumpy from periods of disuse.

I'm not an A&P, but 27 hours in 2 years certainly qualifies as disuse; but I wouldn't necessarily discount the aircraft if the answers to the above questions satisfy you.

If this is an aircraft on your short list, I'd have a trusted A&P dig into it for you.
 
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Depends, is it a continental or a lycoming. Has it been stored in a heated hangar? Is it located in low humidity state?
 
Lack of use is murder on engines. Depending on points made by clip4 above it could be better or worse. If it wasn't pickled properly it'll never last to TBO. No way to see the cam without pulling a cylinder. Might be worth it? But just one won't show you everything.
You say started making metal - what kind? Usually after sitting, cam lobes and lifter faces rust and with use get much worse, spreading metal all over through the oil to bearings etc.
Price it as if it needs another overhaul. Lots of unused planes get sold, engine shops love them.....

https://www.lycoming.com/content/frequency-flight-and-its-affect-engine
 
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Blue Doughnut said:
Where is the plane, and what are the compression ratios if you happen to know? And if you are able to believe the seller, how much oil is it consuming? A borescope for corrosion and pitting would also be wise.

You're definitely thinking about the right things as planes often wake up grumpy from periods of disuse.

I'm not an A&P, but 27 hours in 2 years certainly qualifies as disuse; but I wouldn't necessarily discount the aircraft if the answers to the above questions satisfy you.

If this is an aircraft on your short list, I'd have a trusted A&P dig into it for you.
Click to expand...

Plane is in the northern Rockies for last 5 yrs, Mobile AL for a few decades prior.

Compressions April 2015- 76 74 77 75 74 76 /80 with 108 hrs SMOH (now at 116 SMOH).

Did not ask the oil consumption question, will do, thank you.

Going to have Savvy do an initial look.
 
Clip4 said:
Depends, is it a continental or a lycoming. Has it been stored in a heated hangar? Is it located in low humidity state?
Click to expand...

Continental. Hangar yes, heated do not know, will ask. Yes, located in low humidity area since new engine.
 
Goofy said:
Lack of use is murder on engines. Depending on points made by clip4 above it could be better or worse. If it wasn't pickled properly it'll never last to TBO. No way to see the cam without pulling a cylinder. Might be worth it? But just one won't show you everything.
You say started making metal - what kind? Usually after sitting, cam lobes and lifter faces rust and with use get much worse, spreading metal all over through the oil to bearings etc.
Price it as if it needs another overhaul. Lots of unused planes get sold, engine shops love them.....

https://www.lycoming.com/content/frequency-flight-and-its-affect-engine
Click to expand...

Logs don't say what kind of metal. Oil change in 2011 showed some metal. A 2 hr flight and recheck was enough to get the engine overhauled.
 
455 Bravo Uniform said:
Continental. Hangar yes, heated do not know, will ask. Yes, located in low humidity area since new engine.
Click to expand...

Environmental moisture has nowhere near the impact as the moisture that accumulates in the case during ground runs. A ground-run engine doesn't get the oil hot enough for long enough to get rid of the water that condenses in there, mixes with the oil, and forms corrosive acids. The water is a product of combustion and is part of the gases that get past piston rings when the engine is cold and clearances are larger. Every year I see several engines badly damaged this way.

Fly it or leave it alone. Ground running does absolutely nothing good for it.
 
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