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To overhaul or not to Overhaul, that is the question-



 
 
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  #1  
Old May 9th 06, 01:12 AM posted to rec.aviation.owning
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Default To overhaul or not to Overhaul, that is the question-

I've had an opportunity recently to purchase a Piper PA28-140- absolute
creme puff cosmetically... but the problem (and reason for the good
cosmetic condition) is that the plane has been sitting in an
enironmentally stable (dry, 50-80 degree ambient temperature) for
almost a decade now.

(For those who responded to my other post, I know this is a huge step
down from what I was looking for, but It would just serve as a
timebuilding local puddlejumper/toy for a few years until I can afford
something better, and at the price, I'm garanteed not to loose anything
on depreciation)

The purchase is for a _very_ good price.

Before she went into the hanger, the ship had 300 hours on a rebuilt
engine (2300 hours TTAF).

I'm getting wildly varying advice from shops. The one shop whose
actually seen her has been assuring me that considering the condition
of storage and the good condition before she went in, He's reasonably
sure (and he's going to confirm/deny with a prepurchase this week) that
all she'll need is to have all of her seals replaced, as well as a good
prelubrication job done. He said that as long as I go through and make
sure that the engine is well lubricated and sealed before I turn it
over even once, then there really shouldn't be any damage worthy of a
rebuild.

The other shop, the one who I have more experience and tend to trust
more (although they tend to be very by-the-book and high-end) has
_adamantly_ insisted that If I get the plane, she will need a full
engine rebuild. They said that even if she hadn't been static for 10
years, Lycoming insists that all O320's be rebuilt at 2000 hours OR 10
years.

Both shops agree about the rest of the necessary work (Avionics, new
struts, new tires, new seatbelts, etc). The only place they disagree
is the engine.

I'm not sure what to think... On one hand I agree, err on the side of
safety. On the other hand, everything I know about engines suggests
that as long as A- there was no opportunity for the introduction of
moisture and B- the engine is fully lubricated/sealed before running,
engine corrosion/wear shouldn't be an issue.

I'd love to hear some of your takes on the situation.

  #2  
Old May 9th 06, 01:14 AM posted to rec.aviation.owning
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Default To overhaul or not to Overhaul, that is the question-

Type correction - she's been sitting in an environmentally stable
_hanger_

  #3  
Old May 9th 06, 01:34 AM posted to rec.aviation.owning
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Default To overhaul or not to Overhaul, that is the question-


"EridanMan" wrote:

The other shop, the one who I have more experience and tend to trust
more (although they tend to be very by-the-book and high-end) has
_adamantly_ insisted that If I get the plane, she will need a full
engine rebuild. They said that even if she hadn't been static for 10
years, Lycoming insists that all O320's be rebuilt at 2000 hours OR 10
years.


They are being unreasonable. Lycoming *recommends* that all O320's be
rebuilt at 2000 hours OR 10 years. It's not cast in stone for a private
owner. My Lyc. O-360 had 2700 hours SMOH when I had it overhauled; it could
easily have gone more.

Both shops agree about the rest of the necessary work (Avionics, new
struts, new tires, new seatbelts, etc). The only place they disagree
is the engine.

I'm not sure what to think... On one hand I agree, err on the side of
safety. On the other hand, everything I know about engines suggests
that as long as A- there was no opportunity for the introduction of
moisture and B- the engine is fully lubricated/sealed before running,
engine corrosion/wear shouldn't be an issue.


Maybe. I'd still worry about the camshaft. Lyc. cam's are notorious for
rusting from disuse. Why not have it opened up and looked at?

--
Dan
C172RG at BFM


  #4  
Old May 9th 06, 01:58 AM posted to rec.aviation.owning
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Default To overhaul or not to Overhaul, that is the question-

My call -
I think it depends on how it was shut down last. Has it had reasonable
oil change intervals before shut down? Has it been fed a lot of 100LL?
Has it been stored under high humidity conditions? Why replace seals?

All are possible considerations but none are necessarily deal killers
in my book. Pull the plugs and do a visual inspection of the cylinders
with a small light dropped thru the opposite plug holes. Assuming it
looks reasonable, change the oil, drain the fuel & the carb bowl,
preheat the crankcase so the startup oil is warm, and go for it.

This engine is closer to being bullet proof than any other. Cam
failure due to corrosion might be a problem so I would check the oil
screens & immediately get an oil analysis sample after a short first
flight.

I have a 172M that at 31 years & 1700 hrs since new still doesn't use
oil between changes. If it did or had any other negative symptoms, I'd
be overhauling it. It never sat for more than a couple of months at a
time though.

I'm sure others will have an opposite opinion. Let us know what you do
& how it turns out. Good luck!

  #5  
Old May 9th 06, 03:02 AM posted to rec.aviation.owning
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Default To overhaul or not to Overhaul, that is the question-

No way to tell for sure. What I would do is go ahead and treat it like
I was going to run with what I got, and see how it goes. After a few
hours of running do a compression test and monitor oil usage. If all is
well, run it till it starts giving oil burn, low compression, power
loss or metal in filter. THEN rebuild. You might get 1000 or more hours
out of it. But as I said, no way to tell for sure.

  #6  
Old May 9th 06, 03:09 AM posted to rec.aviation.owning
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Default To overhaul or not to Overhaul, that is the question-


"EridanMan" wrote in message
oups.com...
I've had an opportunity recently to purchase a Piper PA28-140- absolute
creme puff cosmetically... but the problem (and reason for the good
cosmetic condition) is that the plane has been sitting in an
enironmentally stable (dry, 50-80 degree ambient temperature) for
almost a decade now.


If it has been sitting 10 years, my guess is that the engine will have rust,
unless it was in an extremely low humidity climate.

Pull a cylinder or two, look at the cylinders, look at the cam, and make a
decision. Pulling the cylinders shouldn't cost a whole lot. A good mechanic
can pull one off and reinstall it in a couple of hours. For someone like
me, it take a bit longer... ;-)

In addition, if the airplane has truly been sitting that long, my guess is
that most of the hydraulic seals will be questionable. Brake cylinders and
the nosewheel strut are the obvious areas for potential trouble.

Maybe the price you're getting *is* incredible, but it is often cheaper to
buy a nice example of the plane you want than to buy a marginal example and
bring it up to nice standards.

KB


  #7  
Old May 9th 06, 06:05 AM posted to rec.aviation.owning
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Default To overhaul or not to Overhaul, that is the question-

EridanMan wrote:
I've had an opportunity recently to purchase a Piper PA28-140- absolute
creme puff cosmetically... but the problem (and reason for the good
cosmetic condition) is that the plane has been sitting in an
enironmentally stable (dry, 50-80 degree ambient temperature) for
almost a decade now.


snip rest

Anything sitting that long should be highly suspect and throughly
inspected before you bet your life on it.

All the "rubber" parts are almost assuredly dried out, ready to
fail, and in need of replacement, and in the case of an aircraft,
the ones in the fuel system and brake system could cause you to
become the occupant of a smoking crater.

Depending on what was done before it was parked and the environment
since, the engine (other that the "rubber" parts) could be in pristine
condition or ready to fail at any second.

What is your life worth to you?

In another life I did a lot of sports cars of dubious quality which
sat for a long time with varied results when fired up.

There is a big difference between an engine failure on an old stored
car engine and an old stored aircraft engine when you are looking for
a place to park it when it fails in service.

--
Jim Pennino

Remove .spam.sux to reply.
  #8  
Old May 9th 06, 08:22 AM posted to rec.aviation.owning
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Default To overhaul or not to Overhaul, that is the question-

EridanMan,

Lycoming insists that all O320's be rebuilt at 2000 hours OR 10
years.


for Part 91?

You omitted an important detail: Was the engine put in long-term
storage condition, including the oil that goes with that?

Also, wouldn't a borescope inspection answer some of the questions? And
how it runs at the first try? And oil analysis? IN any case, a
categoric rebuild seems unnecessary.

However, with all the other things you mention (seals, avionics,
interior), I really have to wonder how this can be a good deal.

--
Thomas Borchert (EDDH)

  #9  
Old May 9th 06, 12:57 PM posted to rec.aviation.owning
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Default To overhaul or not to Overhaul, that is the question-

: The purchase is for a _very_ good price.

What you are describing is almost completely the same situation as the plane
that we bought coming up on 4 years ago. It was a PA28-140 with a -180 engine in
it... only 5 hours since overhauled, but 8 years earlier. It didn't have an interior
or any avionics, but the price was really good.

We bought it anyway, and then discovered that not only was there no time on
the engine, it wasn't even broken in! It had chrome cylinders (notoriouly difficult
to break in), and I put 50 hours or so on it burning a quart every 4-5 hours or so.
There were two "soft" cylinders pulling it through. Between that and some "morning
sickness" and power losses indicating sticking valves, we pulled the jugs and had them
IRAN'd. I took a good look at the cam with them off and didn't see any evidence of
spalling, pitting, or rusting.

Since then, I've installed a full digital IFR stack, earned an instrument
rating with it, put in an interior, and flew it to Alaska and back (among other things
with the 500 hours we've put on it).

In short, take the advice of expecting large-ish repairs in the short-term.
In our case, I (probably mistakenly) thought that we were buying a "fixer-upper," but
at least it was mechanically sound and flyable immediately. I developed a good
repoire with my mechanic, and did all the avionics installations myself from used
equipment... so from nothing to King digital IFR stack was less than $5k. That's not
normal. To have done it the "normal" way, the same stack would probably have cost
$15k to buy and have installed.

Interior was the same... cost $1200 and a few weeks' worth of my time doing
prep work and doing the install after the upholstery shop made up the panels and
recovered the seats.

Other maintenance has been fairly "normal." In short, I guess I'm saying you
may get off OK, but you may need to do some big work. If you're mechanically inclined
and have a mechanic you can work with, you could get by inexpensively. If you have to
have all the work done, it'll likely cost you more than it's worth. If the top end
needs work like ours does, it isn't too bad. If the cam is rusted and spalled, you
gotta split the cases which is a good fraction of the labor for a full overhaul.

-Cory


--

************************************************** ***********************
* Cory Papenfuss, Ph.D., PPSEL-IA *
* Electrical Engineering *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

  #10  
Old May 10th 06, 01:07 AM posted to rec.aviation.owning
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Default To overhaul or not to Overhaul, that is the question-

I'm a mechanically inclined type, and this is _exactly_ my plan.

I'm looking for a solid, corrosion free 'base' to start building up a
plane... Think of it as 'experimental aviation light'- I don't want to
wait 3000 hours to start flying, but I don't mind a plane that's going
to take some elbow-grease along with the purchase price.

The low time airframe and complete lack of corrosion are two huge
pluses. It also seems like there is quite a cult following for the old
Hershey-wing Pipers, aerodynamic modifications are plentiful and
inexpensive (how useful they are remains to be seen of course), but I
still like the idea.

The ship is going to need an IFR stack (currently VFR only, and
eventually I want my IFR ticket), but as you said, King IFR stacks are
amazingly cheap right now (I guess everyone is dumping them in the rush
to glass, a trend that will only accellerate IMHO).

I got a chance to get my elbows dirty yesterday in the plane (before
hand I was dealing with world of mouth from a friend, the plane is
being sold by an aquaintance of sed friend).

The wings and sheetmetal was pristine (original stenciling still
clearly visible, you could probably eat of the wing spar metal, etc).
interior was a mixed bag, plastics are all flawless, but the panel is
in sorry shape and the plane doesn't even have an intercom (previous
owner used speaker+handheld). Seats Rails were flawless (and all seat
adjustments), but the seats themselves need re-upulstering (and the
arm-rests were all cracking and showing their internal foam).

The only real 'ugly' I came across was the Fuel tanks... red goo in
both. I'm already pricing salvage replacement tanks and fuel system.

I'm amazed how simple the plane is... the entire fuel system looks well
within my mechanical abilities (and the parts don't seem to be too
bad). I did confirm that the fuel tank, while ugly inside, did not
leak within the wing (one of my concerns).

I'd also probably do the interior work myself (within legality in
regards to the panel, of course).

I'm having a mechanic go over her tomorrow to find anything I missed in
my rather thorough inspection... assuming there aren't any
showstoppers, I'm ready to put down a deposit.

My final determination came down to one simple equasion... Purchase
price + Engine Overhaul Value of comparible planes on barnstormers...

What else can I say?

 




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