Cracked cylinder: Typical cause?

But don't buy them from J & J Air parts in Texas.


Trip


In article jic8d.168563$MQ5.108036@attbi_s52, says...

On a similar note, if a cylinder compression was low, would you rebuild
it,
or buy a new one?

It depends. Depending on the problem, and age of the cylinder, I'd probably
still buy new.

When you look at a new Millennium cylinder, and see where they have beefed
up the areas most likely to crack, it's an easy choice.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Jay Honeck" wrote

It depends. Depending on the problem, and age of the cylinder, I'd
probably
still buy new.

When you look at a new Millennium cylinder, and see where they have beefed
up the areas most likely to crack, it's an easy choice.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

The reason I was asking is that the plane I'm buying needed a cylinder
rebuilt, and the owner elected to have it rebuilt rather than buy a new one.
I'm sure it will be OK...but for how long?
All I can say is that the owner has been extremely agreeable.
We had that agreement that he may or may not fix anything above $500.
So far, the annual has been about $4K, and he has been more than happy to
fix everything (including the cylinder rebuild).

Adam,

On a similar note, if a cylinder compression was low, would you rebuild
it,
or buy a new one?

If it's low e.g. because an exhaust valve is leaking rebuilding would make
sense, would'nt it?

Regards

Kai

Adam,


On a similar note, if a cylinder compression was low, would you rebuild

it,

or buy a new one?

If you have a bad valve there's no rebuilding to do. You put in a new
valve and go flying.

Jay Honeck wrote:

If you buy a rebuilt cylinder you do not know if it has 500 hours or
5000 hours. You also can not always tell if it has already cracked
and been welded.


Why in the world would anyone buy a rebuilt cylinder nowadays?

The price differential between new and used is so small

Where are you shopping? A new cylinder is about $1K. Around here
overhauled cylinders, chromed are $350.


-- and the risks are
just too great.



Heck, I wouldn't put a rebuilt cylinder on my CAR (not that any such thing
is ever necessary on modern automobiles), let alone an airplane.

I have 6 chromed first run cylinders on my 182, can't see why you
wouldn't go that way.

"Jay Honeck" wrote in message news:8Q38d.171959$D%.3931@attbi_s51...
If you buy a rebuilt cylinder you do not know if it has 500 hours or
5000 hours. You also can not always tell if it has already cracked
and been welded.

Why in the world would anyone buy a rebuilt cylinder nowadays?


There does seem to be a general opinion that new Continental cylinders
are not a good buy. Both L&C seem to have lost their best
metallurgical engineers.

Peter R. wrote
What would be the most likely reason a cylinder in a high-time engine
would crack, old-age or poor temperature management on a descent?

While both are possible, neither is most likely.

When considering what causes an aviation problem, you need to consider
what aspect is most under the control of the FAA. That will be the
biggest problem.

In this case, the FAA controls design (through the awarding of a type
certificate or STC or writing the TSO) and manufacturing/quality
control (through the awarding of a production certificate or PMA) so
those are in fact the two most likely reasons for cylinder cracking -
poor design and poor QC.

Michael

With everyone criticizing Lycoming and Continental, I will point out a
couple of items. I have Lycoming 1996 0-360 in my Husky. Since NEW, it
has 2200 tach time (about 2600 Hobbs). No oil usage, no metal in the
filter, oil analysis is good and makes above 70 on the compression.
Goes as fast and climbs as well as when new. Engine has never had any
engine components serviced. (accessories like alternator, yes).

I know of a certain government aircraft (two actually), Cessna 185's
that have AWAYS made TBO. They automatically replace the engine at TBO
with Continental factory rebuilt. They have gone through 6 engines
over the years, and EVERY engine has made TBO without cylinder
replacments. The 185 engines are notorious for cracked cylinders.

Then I hear of rebuilt engines from whoever, cracked cylinders,
rebuilt cylinders etc. But the above are factory Lycoming and factory
Continental. All stock factory components. And they did just fine.

Doug wrote:

With everyone criticizing Lycoming and Continental, I will point out a
couple of items. I have Lycoming 1996 0-360 in my Husky. Since NEW, it
has 2200 tach time (about 2600 Hobbs). No oil usage, no metal in the
filter, oil analysis is good and makes above 70 on the compression.
Goes as fast and climbs as well as when new. Engine has never had any
engine components serviced. (accessories like alternator, yes).

Lyc's last a long time. But look at the prices of new ones from the
factory, they are more than two and a half times the cost of a similar
Continental. This is because Lyc is recouping the cost of their
crankshaft debacle of a couple years ago. The cost of a new Cessna 206
could be reduced by 80 Grand if they simply switched back to a Continental.



I know of a certain government aircraft (two actually), Cessna 185's
that have AWAYS made TBO. They automatically replace the engine at TBO
with Continental factory rebuilt. They have gone through 6 engines
over the years, and EVERY engine has made TBO without cylinder
replacments. The 185 engines are notorious for cracked cylinders.

Then I hear of rebuilt engines from whoever, cracked cylinders,
rebuilt cylinders etc. But the above are factory Lycoming and factory
Continental. All stock factory components. And they did just fine.

Buddy of mine has a PA-12 with 6500 SMOH and 3500 since the last top.