exceeding TBO on Continental 0200-A

[Marty from Sunny Florida]

Hello everyone. I'm continuing my quest to buy the best deal in America
today.

Another option I've looked at is purchasing a low price Cessna with an
engine that's past it's recommended time between major overhaul. Some of the
sellers I've spoken with are insistent that recomended times aren't
important, it's the condition of the engine that matters (ie. not making
metal).

I'd like some feedback from people who've purchased aircraft with high time
engines. What should I expect, and what precautions can be taken to keep a
high time engine flying (with the plane attached).

thanks,
m.

[Rosspilot]

>
>Hello everyone. I'm continuing my quest to buy the best deal in America
>today.
>

If you're talking about acquiring something that you are going to haul yourself
and others up and away from the earth's surface, and move through the
atmosphere
and safely return yourself and others to earth, alive and well, I respectfully
suggest
reviewing your priorities.

And what do you mean by "the best deal" anyway? How do you measure that?




www.Rosspilot.com

[Jim Weir]

When the engine starts making metal, you've got an expensive overhaul on your
hands. Normally, you can get two, sometimes three, major overhauls/repairs (see
another thread for which of these words you want to use) out of the bottom end
before you have to undersize the crank. If you go until the engine makes metal,
and depending on what metal it is, you may not even have a reusable crank when
you pull it apart, and now you are really talking MONEY.

Same for the jugs. If it is pistons that are making metal, then they are
getting loose and sloppy in the bore and this accelerates wear tremendously.
Exhaust valves are in the neighborhood of $200 apiece, and the guides are not
far behind if you have to machine the guide bore.

Wear is not linear. It is exponential, and the longer you go past RTBO, the
further you are up on the exponential curve.

Now, if you are REALLY looking to fly inexpensively, buy a relatively high time
engine, put a couple of hundred hours on it, and then figure out which end of
the wrench gets greasy. Find yourself a mechanic willing to do an "owner
assisted" repair/overhaul. The O-200 is about as bonehead simple as you can
get, and all the machine work is done by an outside facility. You get back
straight/chromed cylinders with the valves installed and lapped, fitted pistons
with fitted rings, case inspected, crank inspected, cam inspected/overhauled,
and the like. You can send out the mags, carb, vacuumpump, and any of the other
accessories you want. From there on it is tinkertoy simple (with expert advice)
to put it back together.

Roughly? Including R&R and labor to dis/assemble? Half.

The HARD part is having the guts to pull it apart yourself. However, with a
digital camera recording every step, putting it back together is a simple
reversal of the process.

Just my 8% of two bits, mindya.

Jim




->Another option I've looked at is purchasing a low price Cessna with an
->engine that's past it's recommended time between major overhaul. Some of the
->sellers I've spoken with are insistent that recomended times aren't
->important, it's the condition of the engine that matters (ie. not making
->metal).

Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

[G.R. Patterson III]

Jim Weir wrote:
>
> The HARD part is having the guts to pull it apart yourself.

I never had any problem taking things apart. It's trying to figure out where the
leftover pieces were supposed to go after I get it back together that gives me
problems. :-)

George Patterson
None of us is as dumb as all of us.

[Michael]

"Marty from Sunny Florida" > wrote
> Another option I've looked at is purchasing a low price Cessna with an
> engine that's past it's recommended time between major overhaul. Some of the
> sellers I've spoken with are insistent that recomended times aren't
> important, it's the condition of the engine that matters (ie. not making
> metal).

That's somewhat but not completely true. Parts do wear. Having said
that, if we're talking about an O-200 that is high in hours but low in
calendar years (say 2000+ hours in less than 10 years) and is not
making metal, not using excessive oil (anything over 1 qt in 5 hours
would be considered excessive for that engine), and has good
compressions - keep running it. I've seen those engines go for 3000+
hours. I've never seen one fail in flight due to causes that could in
any way be related to running past TBO.

Just realize that an engine won't run forever - you can exceed TBO,
but not indefinitely. It WILL start making metal, using excessive
oil, having low compressions, etc.

> I'd like some feedback from people who've purchased aircraft with high time
> engines. What should I expect, and what precautions can be taken to keep a
> high time engine flying (with the plane attached).

I bought a plane with an O-320 with 2200 hours. I put another 150 on
it the following year. Then overhauled because a bolt was cracked and
the case had to be split to replace it anyway.

Crank passed, cam passed, couple of gears were replaced. Nominal
overhaul. Had the bolt not cracked, I likely would have gotten
another 100-300 hours out of it.

Michael

[Dave]

As with anything, it all depends....

How many hours has it flown per year over the past 5 years. In those
5 years, what do the engine logs show? Any top overhauls, cylinder
replacements, etc.? I bought a Cherokee 6-300 with about 1750 SMOH on
it. The airframe, interior and panel were in 10+ condition, so I
compromised on the engine time in favor of the rest. Logs were clean,
and it had been flown a lot over the prior 5 years. Well, about 100
hrs and an annual insp. later, it's still a champ with good
compression, low oil consump and no metal. I'm confident I'll at
least make it to 2000.

I had a Cherokee 140 that I bought with 1830 SMOH on it. It had a top
overhaul at 1500, and fairly regular use over the previous years. I
babied it and did 50 hr oil changes. It flew to 2200, and it was
still doing well, but I had the budget and time so I had a Penn Yan
exchange done for a 0 SMOH powerplant.

If, on the other hand, the engine has had low usage(like 30-40
hrs/year) over the past 5, and/or maybe some work on the engine beyond
the standard inspections and routine maintenance, you should think
twice.

The nice thing about getting a high time engine in good condition is
that those last hours, whether they are 10 or 200, are essentially
'free' because you've already factored in the price of an
overhaul(right??!) down the road. Once you accomplish that, the slate
is wiped clean and the 'new' engine is all yours and you should have
fewer worries percolating around in the back of your head because you
know how it's been flown(once you break it in).

[Tom Sixkiller]

"Marty from Sunny Florida" > wrote in message
...
> Hello everyone. I'm continuing my quest to buy the best deal in America
> today.
>
> Another option I've looked at is purchasing a low price Cessna with an
> engine that's past it's recommended time between major overhaul. Some of
the
> sellers I've spoken with are insistent that recomended times aren't
> important, it's the condition of the engine that matters (ie. not making
> metal).
>
> I'd like some feedback from people who've purchased aircraft with high
time
> engines. What should I expect, and what precautions can be taken to keep a
> high time engine flying (with the plane attached).
>

Just so you have the right perspective about TBO...

The Savvy Aviator #4: Debunking TBO
http://www.avweb.com/news/columns/187037-1.html

[kage]

**********Hello everyone. I'm continuing my quest to buy the best deal in
America
today.*************

Let'see. There are 106 C-150's in TAP right now. And to get a "good deal"
you plan on buying a run out and continue to operate it?

Sellers will LOVE you!

Karl

[David Lesher]

Jim Weir > writes:

>When the engine starts making metal, you've got an expensive overhaul on your
>hands. Normally, you can get two, sometimes three, major overhauls/repairs (see
>another thread for which of these words you want to use) out of the bottom end
>before you have to undersize the crank.

Do they resurface aircraft cranks? When marine/truck/pricey auto
cranks get worn undersize, they are:

Built back up to the right diameter. A welder goes back and
forth across each bearing surface as the crank rotates;
building up a solid surface.

The crank is chucked into a "crankshaft lathe"... It's then
spun slowly while a toolpost grinding wheel grinds each surface
back to spec.

~Last step is to redrill the oil passages down the crank.

Now, it's almost straightforward for the main bearings -- they are
in line with the axis of the crank. But the *rod* bearings are a
different story. What's done there is the chucks at both ends of
the lathe have offsets - you shift them sidewise until the rod
bearing in question *is* centered. (The two chucks are kept in exact
sync by a driveshaft under the tool bed.)

The whole deal looks like f*$(^9& magic when you see it in progress.
The crank ends, mains and other throws are flailing around seemingly
randomly...but that one rod bearing is dead bang centered....

(The lathe I saw had a ~16' yes sixteen foot marine crank in it.)


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

[Bela P. Havasreti]

On Fri, 11 Jun 2004 05:02:26 +0000 (UTC), David Lesher
> wrote:

Not only do (most?) engine manufacturers not allow the automotive
process you describe (to "save" a crank), there are some that don't
allow any grinding at all to go undersize on the journals.

Truth be known, with the "average" light aircraft/engine, you can go 2
or 3+ overhauls (properly operated / maintained) without buggering up
a crankshaft.

P-51 owners tend to rebuild the bottom end (spare engines on hand)
every so often precisely for that reason..... i.e., new/serviceable
cranks are impossible to find and/or obscenely expensive, and in
the long run, it's cheaper to re-bearing/rebuild the engine than it is
to run it until it starts making metal.

Bela P. Havasreti

>Jim Weir > writes:
>
>>When the engine starts making metal, you've got an expensive overhaul on your
>>hands. Normally, you can get two, sometimes three, major overhauls/repairs (see
>>another thread for which of these words you want to use) out of the bottom end
>>before you have to undersize the crank.
>
>Do they resurface aircraft cranks? When marine/truck/pricey auto
>cranks get worn undersize, they are:
>
> Built back up to the right diameter. A welder goes back and
> forth across each bearing surface as the crank rotates;
> building up a solid surface.
>
> The crank is chucked into a "crankshaft lathe"... It's then
> spun slowly while a toolpost grinding wheel grinds each surface
> back to spec.
>
> ~Last step is to redrill the oil passages down the crank.
>
>Now, it's almost straightforward for the main bearings -- they are
>in line with the axis of the crank. But the *rod* bearings are a
>different story. What's done there is the chucks at both ends of
>the lathe have offsets - you shift them sidewise until the rod
>bearing in question *is* centered. (The two chucks are kept in exact
>sync by a driveshaft under the tool bed.)
>
>The whole deal looks like f*$(^9& magic when you see it in progress.
>The crank ends, mains and other throws are flailing around seemingly
>randomly...but that one rod bearing is dead bang centered....
>
>(The lathe I saw had a ~16' yes sixteen foot marine crank in it.)