The results of not flying...

My A&P is doing a field overhaul on an O-540 (he used to own an engine
shop, and did our overhaul back in '02), and he showed me what happens
to a plane that isn't flown often.

Two valve lifters (the things that rides on the camshaft) have faces
that look like someone took a hatchet to them. The cam lobe that rode
on this valve actually isn't too bad (although it didn't pass spec, so
they're getting a new camshaft), but only because it wasn't flown
enough to completely destroy it before they found a cracked case,
which necessitated a tear-down.

This plane (a Lance) sat for years, then was flown only very
occasionally, and then sat for another nine months while the owner
fought to get his medical back. By the time he finally got it back,
the engine was toast from inactivity.

My A&P's diagnosis: Rust built up on the face of the cam, the lifter,
or both, after all the oil had run off over time. Starting the engine
then put microscopic scratches in the face of both, and started the
process of deterioration.

Scary thing is that the engine ran fine (other than the prodigious
amounts of oil emanating from the cracked case) -- the owner never
knew his engine was beating itself to death internally...

Doctor's orders: FLY OFTEN!

:-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Jay Honeck" wrote:

Two valve lifters (the things that rides on the camshaft) have faces
that look like someone took a hatchet to them.

Inactive Lycomings are particularly susceptible to this, so say the engine
gurus.

Doctor's orders: FLY OFTEN!

Aye-aye, Doc! Bay Minette tonight, Baton Rouge tomorrow.

--
Dan
T-182T at BFM

On Sep 27, 9:21 am, "Dan Luke" wrote:
"Jay Honeck" wrote:

Two valve lifters (the things that rides on the camshaft) have faces
that look like someone took a hatchet to them.

Inactive Lycomings are particularly susceptible to this, so say the engine
gurus.

Doctor's orders: FLY OFTEN!

Aye-aye, Doc! Bay Minette tonight, Baton Rouge tomorrow.

--
Dan
T-182T at BFM

It's much worse if the owner goes to the airport, starts and runs the
engine for awhile, then shuts it down. A cold cylinder leaks
considerable combustion gases past the rings, and since those gases
contain water vapor and the crankcase is relatively cool, the vapors
condense and leave water in the case. That water mixes with the oil
over time and, in the presence of metal, creates acids that eat the
engine from the inside.
So, unless you plan to fly it and get that oil temp up to at
least 160 degrees for a half hour or so to boil off the water that
forms during warmup, it shouldn't be started at all.
I often hear of some airplane for sale whose owner was so
conscientious about running it up now and again, but couldn't fly it.
Such engines are usually in trouble soon after they start flying
again.

Dan

Jay Honeck wrote:

Scary thing is that the engine ran fine (other than the prodigious
amounts of oil emanating from the cracked case) -- the owner never
knew his engine was beating itself to death internally...


I've known numerous pilots that have rescued ramp queens that had been
sitting for years. Most of the engines "ran fine" soon after the
resurrection was complete. It was usually 50-100 hrs. down the road that the
corrosion damage to the cam got bad enough to be obvious.

Whenever a prospective buyer asks me about a plane that's been sitting for
a prolonged period, I tell 'em to (at a minimum) pull some jugs and take a
look at the interior of the engine. If you don't bother going that far, the
rest is a (fairly high stakes) crapshoot.

John Galban=====N4BQ (PA28-180)


John Galban=====N4BQ (PA28-180)

--
Message posted via http://www.aviationkb.com

.stuff snipped
I've known numerous pilots that have rescued ramp queens that had been
sitting for years. Most of the engines "ran fine" soon after the
resurrection was complete. It was usually 50-100 hrs. down the road that the
corrosion damage to the cam got bad enough to be obvious.
.stuff snipped

I am wondering if it would be considered in bad taste to ask a
prospective seller to produce his/her personal logbook (or the books of
those flying the beast) in order to establish the plane's flying
history? You can check the plane's books to get a history of hours
between annuals.

A concern we had when buying was that the plane (74 Cherokee 140 - 150hp
0-320) had a history of being purchased, being flown for 30-40 hours
(usually over a year's time), and then sold again. The thing had also
had a field overhaul 400 hours into its life for a prop strike. What
saved us from having too big a risk was that the previous owner to us
trained in it for 150 hours of fairly regular flying. He spent a fortune
replacing things, including one cylinder. If it was going to go South,
it would have likely done so with him. We got it at 1200 hours since new
(and 20 years) but it was really an 800SMOH/17 years engine. Normally,
those numbers can be disastrous. But, we got the plane to 1800 hours
before it finally was burning a quart an hour and compressions sagged.

Looking back, I am amazed the thing got that far towards TBO. With
moderate abuse (not flying), it ran for 1400 hours before compressions
went down and oil usage was at the limit. It appears that it never sat
quite long enough to do the Lycoming cam scrub self destruct thing.

Ironically, the owner moved up to another low time Piper, this time with
an 0-360 in a Cherokee 180. Within weeks, it started to idle a bit rough
and it turned out that one cam lobe was nearly gone. So, he dodged the
bullet with the plane he sold us and got it on the next one. Weird luck.

Of course, as newbies to airplane ownership 13 years ago, we knew
nothing of the risks we were taking back then. I remember only thinking
that the plane had not flown a lot of hours in all those years based on
a book I read about buying airplanes. And, it turned out O.K. Maybe that
is why we get into such disagreements on this group when someone gives
out advice that seems to counter another's experience. It really IS a
crap shoot with these engines.

Good Luck,
Mike

"Mike Spera" wrote in message
...
...
I am wondering if it would be considered in bad taste to ask a prospective
seller to produce his/her personal logbook (or the books of those flying
the beast) in order to establish the plane's flying history? You can check
the plane's books to get a history of hours between annuals.
...
Mike

Personally, I might provide a description but I would not be interested in
letting you pour over my log books.

On the other hand, why would you need to? The plane's logbooks tell the real
story. You have tach hours at annuals, oil changes, and other maintenance. I
think that provides a better and more accurate view into the flying history
of the plane.

-------------------------------
Travis
Lake N3094P
PWK

On the other hand, why would you need to? The plane's logbooks tell the real
story. You have tach hours at annuals, oil changes, and other maintenance. I
think that provides a better and more accurate view into the flying history
of the plane.

Well, yes and no. Some logs are better than others.

For example, I am a perfectionist about my logs. Everything gets
logged, no mattter how seemingly insignificant.

Atlas' previous owner, however, didn't bother to log oil changes. He
logged major work, but just didn't bother to fill in the oil changes.
Why? Lazy, I suppose -- but I *know* he did them.

Personally, I'd have no trouble at all showing a prospective buyer my
personal logs, if requested. What harm can come of it?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Jay Honeck wrote:



For example, I am a perfectionist about my logs. Everything gets
logged, no mattter how seemingly insignificant.


Gas? Air in the tires? A quart of oil?

Jay Honeck wrote in
oups.com:

Personally, I'd have no trouble at all showing a prospective buyer
my personal logs, if requested. What harm can come of it?


True but it may not tell the whole story. A friend of mine had a C-152
that he wanted to sell but couldn't fly it because of his medical
issues. He asked me to put time on the plane to hold down
deterioration and keep the engine in shape.


--

On the other hand, why would you need to? The plane's logbooks tell the real
story. You have tach hours at annuals, oil changes, and other maintenance. I
think that provides a better and more accurate view into the flying history
of the plane.

If the airplane has a journey log, fine. But if all you have is hours
between annual, that's not very useful. A plane that's flown an hour
twice a month is a better bet than one that's flown 6 hours every 4
months.