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Dormant RV-6

jmcanty3

jmcanty3

Active Member
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
 
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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
 
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
 
Hangared in Buffalo, NY. Our moisture is generally frozen. We do have a few muggy weeks in the summer. No salt though.
 
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!
 
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!
 
jmcanty3 said:
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
Click to expand...
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.
 
My experience

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
 
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
 
I had a friend (AP) buy a 25 yr old Grumman with 20 hrs on it since new,located on the coast in Austrailia. After it was shipped back here, we pulled the engine, sent to reputable shop where it was torn down, inspected and reassembled with little invested. Engine is still basically new .
 
Core value only since it is very close to the 12 year Lycoming TBO.

As said above, pull a cylinder and bore-scope the cam and that cylinder. Also pull the mags and look at the accessory gears. You might have found gold but you will not know until you dig for it. If it does need to be pulled apart, a field OH should be relatively inexpensive.
 
Thanks!!

Thanks for all of the great replies guys. I have never owned an aircraft, so this is very helpful.

If I chose to do a field overhaul, as suggested by some, anyone have experience with a good shop in the upstate NY area? I contacted Penn Yan and they are quoting 23k for an overhaul :eek:
 
jmcanty3 said:
Thanks for all of the great replies guys. I have never owned an aircraft, so this is very helpful.

If I chose to do a field overhaul, as suggested by some, anyone have experience with a good shop in the upstate NY area? I contacted Penn Yan and they are quoting 23k for an overhaul :eek:
Click to expand...

An experienced A&P can do an IRAN for around 2500 plus labor and additional parts (e.g. cam).
 
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Raymo said:
Core value only since it is very close to the 12 year Lycoming TBO.

As said above, pull a cylinder and bore-scope the cam and that cylinder. Also pull the mags and look at the accessory gears. You might have found gold but you will not know until you dig for it. If it does need to be pulled apart, a field OH should be relatively inexpensive.
Click to expand...

The cost of complying with Lycoming SB 240V could be expensive in and of itself.
To call it an overhaul, compliance would be mandatory. That is why it has been suggested that to do an IRAN.
 
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jetjok said:
The cost of complying with Lycoming SB 240V could be expensive in and of itself.
To call it an overhaul, compliance would be mandatory. That is why it has been suggested that do an IRAN.
Click to expand...

Good point. I was thinking IRAN but said OH. Corrected my post.
 
If you can get the plane for core value then do not do anything. A rusted cam will not cause a catastrophic failure, so the plane will be plenty safe to fly. fly it and perform routine oil analysis to check for problems. If nothing shows up in 200 hours then I would say you got a great deal. If a problem shows up then you can have it rebuilt and you got a fair deal.
Do not do any exploratory maintenance or you will be in for a rebuild sooner than if you just leave it alone.
 
Did you folks read MANIFESTO? It would be interesting to get Mike's opinion. Just a thought.... Best of luck in your decision!
 
the capt chicken

pull the cylinders and take a look, if look ok, start her up and check EVERY THING !! drain the oil. send out to be checked , re oil and 5hrs on it , then re ck !! you may be surprised that ALL IS WELL. i ve seen it done many times
 
Bill Dicus said:
Did you folks read MANIFESTO? It would be interesting to get Mike's opinion. Just a thought.... Best of luck in your decision!
Click to expand...

Bill,
Having read some of Mr. Busch's articles and his stated philosophy for "minimalist" practices, I think I know what you are saying. But, might you elaborate for the OP?
 
Inactivity

Assuming no corrosion is found: If you are going to fly this plane with confidence and have family and friends as passengers I would go thru fuel and ignition systems. Replace the fuel and oil hoses. Carb and mags should at least get a teardown Insp or better o/h by a real shop.

Don Broussard
A&P-IA-ATP

RV 9 rebuild in progress
N14DB reserved
 
Dormant 6

Thanks JetJock... Mike Busch is a highly experienced A&P and aviation writer who also offers services to pilots for interpretation/advice about engine parameter downloads from modern instruments (Savvy analysis). He wrote a very interesting book called "Manifesto." He is a maintenance minimalist. He describes the findings of a Brit named Waddington who pioneered minimalist on condition maintenance for the British operated B-24 anti-sub aircraft in WWII rather than the extensive and invasive 50 hour checks previously used. Results were amazingly good. He found that some scheduled maintenance caused many more problems than it prevented. The info was classified I think until 1973. Before that two men with United Airlines named Stanley Nowlan (engineer) and Howard Heap (mathematician) found the same thing independently. Mike says that the airlines, military and high end jets of all types use this approach now and that General Aviation is stuck in the last century as to maintenance. I think the book is well-reasoned and a very worthwhile read. Mike feels that a significant percentage of GA accidents are caused by what he calls "Maintenance Induced Failures (MIF's). I think Mike would recommend some basic checks and maintenance followed by a period of operation (without overhaul) as one poster already suggested - but the only way to know would be to consult Mike and see what he says. Get the book if it sounds interesting, check with Mike and let us know what you decide! And good luck...
 
or...do the fuel and mag stuff as mentioned, ground run it to lube the cylinders and polish what ever rust is on the rings or walls, then do a leak down test. oil analysis. pull rocker covers off and check gross lift and any obvious play in valve train....it may be ok, then see how much oil it uses and go from there.
 
EAA Webinars

Mike Busch has a ton of webinars on EAA's website, I listened to many of them to get my arms around buying (and maintaining) a GA aircraft.

Listing found here at Mike's website:

https://www.savvymx.com/index.php/webinar

Pertinent webinars to this particular topic are these:

Reliability Centered Maintenance

Say No to Useless Maintenance

How Healthy is Your Engine?

MIF's and the Post Maintenance Test Flight

If you haven't completed the purchase of the aircraft yet, his discussion on the "trap" of using an annual vs a "pre-buy" inspection to determine aircraft condition is worth the price of admission in his All about Annuals webinar.

Great way to spend a cold winter's evening is in a comfy chair with the beverage of your choice and one of these webinar's playing on the computer.

Good luck with it,

Rob S.
 
Dormant RV6

First buy the airplane at a bargain price... if you don't then let me know and I might...

Remove the top plugs and fill all the cylinders with Marvel Mystery Oil. Put a bucket under the exhaust as you will definitely get flow through the open exhaust port and let things sit overnight or a couple of days.

In the meantime you can get rid of old fuel from the tanks, inspect fuel lines and anything rubber and inspect the gascolator.

Back on the engine, leave the top plugs out to avoid any hydraulic lock and - making sure the mags are off - start turning the prop by hand. The idea is you want everything to get lubed up good likely removing any surface rust from the cyls and rings in the process. More revolutions are better than less but you don't have to do it all at once either. Obviously if you hear or feel something weird you will be in for more serious maintenance.

Drain all the oil, pull the bottom plugs and clean all of them. You might be surprised at the junk you see on the lower plugs as the MMO will tend to break down the carbon deposits as well as remove rust.

Fill with aviation oil and if all else checks out on the airplane put a few gallons of clean fuel in the tank and start her up.

Pick a good day and run the engine for an hour or so putting it through its paces and watching your temps. Good idea to borescope what you can without any disassembly. If all is well, change the oil and filter again and go fly.

This is not a cure all if you have serious problems but if the only concern is that its been sitting unused its certainly worth a try. Cheap and very effective a high percentage of the time.

Some cautions are to not turn the prop before the MMO as all you are doing is scraping rust along the cyl walls with the rings. And check and recheck your compression after putting a few hours on the engine. Watch your oild sample for any metal after the first oil change. I love getting old airplanes to fly again, it hurts to see them grounded...Good luck!
 
It's good to see a few pragmatists answering. :) A lot of what's been said is what I was hinting at in my 1st post. Many years ago right after I started flying, I bought a Thorp T-18 that had sat up unflown on a trailer in a garage for close to a decade here in central Mississippi. The ink was still wet on my pilot's license, but I was lucky to have knowledgeable (and pragmatic) friends. They said to do the obvious cursory checks and fly. The only issue I had was that the build was old enough that it still had some very old style coils in the mags that were prone to failure. I discovered each failure during preflight runnup, ordered a coil, & replaced/flew. Other than that, no problems until a tornado ate the plane out in Norman OK.

But check the interior of the airframe carefully, if rodents are an issue in upstate NY like they are here in MS. A friend stored a disassembled Cub in a barn, and when he retrieved it, there was almost nothing left of the aluminum wing spars after mice nested on them for years. Their urine is basically mild acid, specifically designed to kill metal a/c parts.

Charlie
 
a couple of different thoughts

I have always believed that the bulk of moisture that rusts Lycoming cams comes from condensation of blow-by moisture inside the crankcase, rather than from exterior atmospheric moisture. This means that the state inside after 10 years depends a lot on how it was shut down the last time, and whether the interior moisture was able to breath out without condensing too much (like if it was a reasonably warm summer day when it was shut down last, or if the dip stick is removed while the engine cools down)

My soaring club bought a C-150/150 (STC for O-320-E2D) a few years ago that had been left idle for a handful of years. It got a fresh annual and went into service. I don't think we were doing oil analysis. Over a period of about 5 months of steady operation (probably 150 hrs) the oil consumption steadily increased and the power output steadily declined, although it otherwise seemed to run fine. It got to where it was using a quart of oil every two hours or so, and could only turn the prop at 2350 rpm at Vy, so we finally sent it in for overhaul. It was basically a core. I didn't hear back specifically, but my assumption is that the cam wore out so there was little valve lift, and the rings wore out, probably from chewing on cam metal dispersed into the oil.

A subtext of the above story is that the engine was "safe" to operate for a long time, until the safety limit was unacceptable power output, not because of immanent mechanical failure.

One thing about the frequent advise to pull a cylinder and have a look -- it seems fairly straightforward to pull a cylinder until you consider how much work is involved in removing the cooling baffles, all nicely sealed with orange RTV, and all the other accessories that have to come off first, at the very least includes the exhaust pipes, cylinder and exhaust temperature probes, induction tube, oil drain tube, and all of the nut-launchers (Adel clamps) that are attached to all those things to support them or other items. By the time all that stuff is off, it starts to seem pretty easy to just pull the whole engine.

Finally -- one poster mentioned something about a 12-year TBO? I never heard of that before. I don't think I've ever seen that in any of my Lycoming documents??? I ran a IO-320 in a Citabria for 3200 hrs before a field overhaul. So I don't know that I'd care much about a 12-year limit.
 
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Cylinders

Some good comments in this thread. The level of corrosion may come down to how fresh the oil was when plane became inactive. 10 hrs or less is likely good, more than that acids level from combustion is higher and can speed up corrosion process. Removing a cylinder is just not that much work, and to remove the second one from the same side takes little effort. Having 2 off on the same side allows the entire interior to be seen including the bottom half of the cylinders still installed on the other side. With the mags off most of the accessory case gears can be seen. While it is true that a wearing cam or tappets rarely fail suddenly it does put steel particles circulating in the oil. You would think the filter would catch everything but these particles can cause scoring on crank & rod journals, piston skirts ect. I've seen it happen and it's a sad thing to buy a crank before its time.

Don Broussard

RV 9 rebuild in progress
 
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scsmith said:
Finally -- one poster mentioned something about a 12-year TBO? I never heard of that before. I don't think I've ever seen that in any of my Lycoming documents??? I ran a IO-320 in a Citabria for 3200 hrs before a field overhaul. So I don't know that I'd care much about a 12-year limit.
Click to expand...

It exists but primarily for commercial operators. When purchasing a plane, it can be used to bring the price of the engine down.
 
Right. TBO for E-AB aircraft rarely has legal teeth. It's primarily used as a bargaining chip.
 
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Thank you all

Thanks to everyone for all of the GREAT commentary. I was very surprised to get all of the wonderful feedback I have received.

Clearly, there is a wide range of options to address this. Each one perhaps just as valid as the next. I will be reaching out to Mike Busch as one poster suggested. His webinars should be required material for anyone operating an aircraft of their own..! (Thanks Bill D.)

Will report back. As for the info - keep it coming!

Thanks,
John
 
Take a look at Lycoming SI 1492D

jmcanty3 said:
Thanks to everyone for all of the GREAT commentary. I was very surprised to get all of the wonderful feedback I have received.

Clearly, there is a wide range of options to address this. Each one perhaps just as valid as the next. I will be reaching out to Mike Busch as one poster suggested. His webinars should be required material for anyone operating an aircraft of their own..! (Thanks Bill D.)

Will report back. As for the info - keep it coming!

Thanks,
John
Click to expand...

John,

Reviewing this thread, it reminded me of something Mike Busch gave a seminar on at last summer's AirVenture about an engine making metal...it might have some relevance in your efforts to bring this -6 back to life.

Mike's main point on the seminar is that you can look at Lycoming SI 1492D for some guidance on how much metal is too much. The service instruction's
topic (and source of metal) was piston pin plugs, but Mike's point was that Lycoming's guidance on how much metal is too much could apply to any engine making some metal, no matter the source.

The upshot is, depending on how much and what size metal is found (and where) the airplane can be considered safe to be flown, with a specific set of criteria determining "next steps" to be accomplished.

Take a look at the SI and it might make you an excellent set of procedures as you resurrect this engine from its slumbers.

SI found here:

http://www.lycoming.com/Portals/0/t...-20-2009)/Piston Pin Plug Wear Inspection.pdf

Good luck with it,

Rob Schroer
 
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