Engine exceeds TBO

I have a lead on a Tcraft with an A-65 engine that has exceeded
recommended TBO. It is my understanding the compression is still good.

How should I approach this engine ( i.e. just assume everything over
1800 hours was a freebee and there is no guarantee it's not about to
poop out)? - Mike

Yup. It's run out, and will need replacement/rebuilding shortly. Like you
said, anything else is gravy.

Don't you have a T-Craft engine?

"Michael Horowitz" wrote in message
...
I have a lead on a Tcraft with an A-65 engine that has exceeded
recommended TBO. It is my understanding the compression is still good.

How should I approach this engine ( i.e. just assume everything over
1800 hours was a freebee and there is no guarantee it's not about to
poop out)? - Mike

"Steve Foley" wrote in message
...

Yup. It's run out,

No, it is not "run out" whatever you mean by that statement. It is still
holding compression, not making metal, and does not have excessive oil
consumption.


and will need replacement/rebuilding shortly.

Really? And what diameter was the crystal ball that you used to make this
determination? I've seen engines that have been taken care of go DOUBLE
TBO. I've seen abused engines go HALF TBO. It is strictly a function of
the care and feeding of the engine.



How should I approach this engine ( i.e. just assume everything over
1800 hours was a freebee and there is no guarantee it's not about to
poop out

Engines don't "poop out". Engines have a slow, steady slide into required
serious maintenance. Every now and again, one will have an unforeseen
catastrophic failure, but those are few and far between.

The other side of that coin is that bearing/crankshaft wear tends to become
exponential after a point in time when it departs from linear. That is, for
a long time (extrapolated by the manufacturer to be "TBO") the wear on the
bearings and the crank is linear. At some point when the bearings get to be
sloppy on the crank, the wear accelerates, and the faster it accelerates,
the faster it accelerates. If you want to play the crankshaft roulette
game, you extend TBO until the bearings start to make metal. Then you pull
the engine down, and if you are lucky, the bearings (the cheap part) took
the hit and left the crank journals intact. If you lose, you grind the
crank UNLESS somebody else played crankshaft roulette before you and the
crank had already been ground to minimums. Now you REALLY have a rough row
to hoe, in that you get to find a replacement crank ... which ain't cheap by
anybody's standards.

Jim

With the information given, and the information requested, I feel my
response was appropriate.

No statement was made regarding compression, making metal, or oil
consumption, how the engine was treated (taken care of or abused).

By "Run Out", I mean that the engine will not serve the owner for many years
to come.

While we are nit-picking, What do you mean by "Making Metal"? I always
thought matter could not be created or destroyed.

(This is a rhetorical question. I know what you mean by making metal, just
as I'm pretty sure you knew what I meant by run out)

"RST Engineering" wrote in message
...

"Steve Foley" wrote in message
...

Yup. It's run out,

No, it is not "run out" whatever you mean by that statement. It is still
holding compression, not making metal, and does not have excessive oil
consumption.


and will need replacement/rebuilding shortly.

Really? And what diameter was the crystal ball that you used to make this
determination? I've seen engines that have been taken care of go DOUBLE
TBO. I've seen abused engines go HALF TBO. It is strictly a function of
the care and feeding of the engine.



How should I approach this engine ( i.e. just assume everything over
1800 hours was a freebee and there is no guarantee it's not about to
poop out

Engines don't "poop out". Engines have a slow, steady slide into required
serious maintenance. Every now and again, one will have an unforeseen
catastrophic failure, but those are few and far between.

The other side of that coin is that bearing/crankshaft wear tends to
become
exponential after a point in time when it departs from linear. That is,
for
a long time (extrapolated by the manufacturer to be "TBO") the wear on the
bearings and the crank is linear. At some point when the bearings get to
be
sloppy on the crank, the wear accelerates, and the faster it accelerates,
the faster it accelerates. If you want to play the crankshaft roulette
game, you extend TBO until the bearings start to make metal. Then you
pull
the engine down, and if you are lucky, the bearings (the cheap part) took
the hit and left the crank journals intact. If you lose, you grind the
crank UNLESS somebody else played crankshaft roulette before you and the
crank had already been ground to minimums. Now you REALLY have a rough
row
to hoe, in that you get to find a replacement crank ... which ain't cheap
by
anybody's standards.

Jim

By "Run Out", I mean that the engine will not serve the owner for many
years
to come.

While we are nit-picking, What do you mean by "Making Metal"? I always
thought matter could not be created or destroyed.

Making Metal, means that particles of the metal lineing on the main bearing
shells is peeling off and showing up in the oil filter and in the oil when
you drain the sump / oil tank. That's a sure indication that the engine
should not be run a minute longer as failure is very near and unpredictible.
We may complain when an A&P grounds an aircraft with metal in the oil
strainer but should be mighty glad when we consider that he's just saved a
falure in the air.
--
..
..
Cheers,
Jonathan Lowe,
Rallye 100
EI-BFR


(This is a rhetorical question. I know what you mean by making metal, just
as I'm pretty sure you knew what I meant by run out)

"RST Engineering" wrote in message
...

"Steve Foley" wrote in message
...

Yup. It's run out,

No, it is not "run out" whatever you mean by that statement. It is
still
holding compression, not making metal, and does not have excessive oil
consumption.


and will need replacement/rebuilding shortly.

Really? And what diameter was the crystal ball that you used to make
this
determination? I've seen engines that have been taken care of go DOUBLE
TBO. I've seen abused engines go HALF TBO. It is strictly a function
of
the care and feeding of the engine.



How should I approach this engine ( i.e. just assume everything over
1800 hours was a freebee and there is no guarantee it's not about to
poop out

Engines don't "poop out". Engines have a slow, steady slide into
required
serious maintenance. Every now and again, one will have an unforeseen
catastrophic failure, but those are few and far between.

The other side of that coin is that bearing/crankshaft wear tends to
become
exponential after a point in time when it departs from linear. That is,
for
a long time (extrapolated by the manufacturer to be "TBO") the wear on
the
bearings and the crank is linear. At some point when the bearings get
to
be
sloppy on the crank, the wear accelerates, and the faster it
accelerates,
the faster it accelerates. If you want to play the crankshaft roulette
game, you extend TBO until the bearings start to make metal. Then you
pull
the engine down, and if you are lucky, the bearings (the cheap part)
took
the hit and left the crank journals intact. If you lose, you grind the
crank UNLESS somebody else played crankshaft roulette before you and the
crank had already been ground to minimums. Now you REALLY have a rough
row
to hoe, in that you get to find a replacement crank ... which ain't
cheap
by
anybody's standards.

Jim

"Jonathan Lowe" wrote in message
...


Making Metal, means that particles of the metal lineing on the main
bearing
shells

Or the rod bearing inserts.



We may complain when an A&P grounds an aircraft

An A&P cannot ground an aircraft. An IA cannot ground an aircraft. There
is argument on both sides that an FAA inspector cannot ground an aircraft.
This is an unfortunate phrase left over from the military, where a mechanic
CAN ground an aircraft. Civilian life is a bit different.

Jim

Then you and Einstein disagree. I know who I believe ...

Jim


"Steve Foley" wrote in message
news:hiQ2f.9552$tU1.1516@trndny07...



While we are nit-picking, What do you mean by "Making Metal"? I always
thought matter could not be created or destroyed.

Touché!



- Steve

"RST Engineering" wrote in message
...
Then you and Einstein disagree. I know who I believe ...

Jim


"Steve Foley" wrote in message
news:hiQ2f.9552$tU1.1516@trndny07...



While we are nit-picking, What do you mean by "Making Metal"? I always
thought matter could not be created or destroyed.

Steve Foley wrote:
With the information given, and the information requested, I feel my
response was appropriate.

No, an appropriate response would have been "I need more information in
order to comment", or "engine life is highly variable and there is no
way to tell if your engine will run 1 more hour or 1,000 more hours."

Your comment was almost certainly wrong, but may have been right in a
very small percentage of cases.


No statement was made regarding compression, making metal, or oil
consumption, how the engine was treated (taken care of or abused).

The OP said the compression was good. There was no comment about metal,
oil consumption, or maintenance though.


By "Run Out", I mean that the engine will not serve the owner for many years
to come.

We knew what you meant, and we know that you don't know what you are
talking about.

Matt

Thanks Jim for making it so clear and understandable.

Jean-Paul
Quebec, Canada
"RST Engineering" wrote in message
...

"Steve Foley" wrote in message
...

Yup. It's run out,

No, it is not "run out" whatever you mean by that statement. It is still
holding compression, not making metal, and does not have excessive oil
consumption.


and will need replacement/rebuilding shortly.

Really? And what diameter was the crystal ball that you used to make this
determination? I've seen engines that have been taken care of go DOUBLE
TBO. I've seen abused engines go HALF TBO. It is strictly a function of
the care and feeding of the engine.



How should I approach this engine ( i.e. just assume everything over
1800 hours was a freebee and there is no guarantee it's not about to
poop out

Engines don't "poop out". Engines have a slow, steady slide into required
serious maintenance. Every now and again, one will have an unforeseen
catastrophic failure, but those are few and far between.

The other side of that coin is that bearing/crankshaft wear tends to
become
exponential after a point in time when it departs from linear. That is,
for
a long time (extrapolated by the manufacturer to be "TBO") the wear on the
bearings and the crank is linear. At some point when the bearings get to
be
sloppy on the crank, the wear accelerates, and the faster it accelerates,
the faster it accelerates. If you want to play the crankshaft roulette
game, you extend TBO until the bearings start to make metal. Then you
pull
the engine down, and if you are lucky, the bearings (the cheap part) took
the hit and left the crank journals intact. If you lose, you grind the
crank UNLESS somebody else played crankshaft roulette before you and the
crank had already been ground to minimums. Now you REALLY have a rough
row
to hoe, in that you get to find a replacement crank ... which ain't cheap
by
anybody's standards.

Jim