Dormant RV-6

jmcanty3 · #1 01-12-2016, 01:58 PM

Looking for some input....knowing full well the broad topic at hand.

I am looking at purchasing a 15 year old RV-6. It has a factory new Lycoming O-360 A4M with 540 TTSN. The drawback here is that the aircraft has been left dormant for a couple years (owner grounded for medical).

My natural concern is corrosion. Is there a good way to check for this without cracking open the case? At this point, I was thinking of valuing the aircraft with the engine core and getting it overhauled myself.

Thoughts, advice?

Thanks,
John

Carl Froehlich · #2 01-12-2016, 02:04 PM

Assuming no effort to fully pickle I agree, the engine is core only value. You can do the bore scope and such but that will miss most of the potential problems.

You might get lucky but I would not fly with it unless overhauled. While you have it pulled back fit Airflow Performance injection instead of overhauling the carburetor.

Carl

rv7charlie · #3 01-12-2016, 02:39 PM

Where has it been hangared? On a coast, or in a dry climate? I'd agree that you're kinda rolling the dice, but ....

The airframe may have more issues than the engine, if it's been stored for that long with no activity around it. Mice really love to nest in spaces like that.

Charlie

jmcanty3 · #4 01-12-2016, 02:43 PM

Hangared in Buffalo, NY. Our moisture is generally frozen. We do have a few muggy weeks in the summer. No salt though.

Canadian_JOY · #5 01-12-2016, 03:02 PM

John - I'm not that far north of you in Ontario. Having watched a pair of my hangar-mates Lycomings turn to rust in what seemed like record time, I would agree that "core value" is all the engine is worth. If the prop is a constant speed prop, the same recommendation applies. It doesn't take much internal corrosion to scrap a prop hub and blade roots. From what I've seen of rusty Lycomings and Hartzell's, there are a lot of parts that go straight onto the scrap pile.

The good news, as pointed out above, is you get a chance to equip the engine as you would like during the overhaul process, or bolt on a used engine and fly on!

jetjok · #6 01-12-2016, 04:22 PM

Why not do a teardown and see what you have? Base the scope of work on what you see when you open the engine. You can also remove two cylinders on the same side, which will allow you to inspect the cam and all the lifters. If you choose to do this, make sure you leave the pistons in the cylinder (pulling them out only far enough to get the piston pins out.
I will be popping the corn, as i am sure that this is going to get interesting!

AZtailwind · #7 01-12-2016, 04:49 PM

Quote:

Originally Posted by jmcanty3

My natural concern is corrosion. Is there a good way to check for this without cracking open the case? At this point, I was thinking of valuing the aircraft with the engine core and getting it overhauled myself.
Thoughts, advice?

Thanks,
John

A quick first step is Bore-scope the top plugs- You will see some rust where the piston rings where sitting if the engine wasn't run. Otherwise I agree with above, these engines need to be exercised.

jpowell13 · #8 01-12-2016, 08:18 PM

I paid $7000 for an O320 that was pickled and stored in a warehouse in Hattisburg, MS for 10 years. Ended up replacing rings in the chrome lined cylinders. Found no rust on the cam. No other problems after 400 hours in my 6A.

It may be that the quality of the hanger is the biggest consideration. Is it insulated, and without any leaks in the ceiling? Might be worth while to just check the humidity in the hanger on a wet day. I heard somewhere that steel doesn't rust unless the humidity gets above 60%. I'm no expert, but i think the main openings that moisture can get into the engine are through the exhaust, carb and breather tube. Just wondering if any of those openings were plugged to keep birds and bugs out? This might have helped with moisture too.

I don't know how, or, if it even applies, but my farm tractor is 33 years old, has always been stored under a shed in high humidity conditions and goes months without being started, but it still gets the job done. John

rivetdriver · #9 01-13-2016, 05:44 AM

I would pull a cylinder.
That allows for a good internal inspection

Randy · #10 01-13-2016, 05:45 AM

I did a similar purchase with a Lake Amphibian one time. Concern about rust on the cam was alleviated via inspection of the cam...

We pulled the cylinder closest to the breather outlet as we figured that is where corrosion would start. It was clean and I flew it for around 500 hrs with no problems.

Randall in Sedona