Compression readings

On a Lycoming O-550, at what compression reading would you start to consider
doing a top or complete overhaul?

In article . net,
" wrote:

On a Lycoming O-550, at what compression reading would you start to consider
doing a top or complete overhaul?

What is a "Lycoming "IO-550"? I know what a lycoming IO-540 is and what
a Continental IO-550 is, but -- a "Lycoming IO-550"??

Anybody who decides to do a complete overhaul because of low compresion
reading/s is a moron. Why is the compression low? How many hours on
the engine, etc? I bought my 182 6.5 years and 900 hours ago with 500
SMOH. My mechanic and I have since learned that the overhaul by Mid
States in Tulsa wasn't a very good one. I have had 5 of my 6 cylinders
off over the years, but just once each. It's always the valves. You
fix them and move on. Perhaps this is why Mid States is no longer in
business. No way I do a complete top much less a complete overhaul just
for bad valves. The occasional oil analysis always comes back normal.



wrote:

On a Lycoming O-550, at what compression reading would you start to consider
doing a top or complete overhaul?

" wrote in message
ink.net...
On a Lycoming O-550, at what compression reading would you start to
consider
doing a top or complete overhaul?




There is no such engine.

KG

I agree. Compression readings are just one indicator of engine health,
along with history, oil analysis, long-term trends, etc. And some engines
are notorious for low compressions now and then - if you did a top overhaul
every time a cylinder dipped below 60, you'd never get a year without
pulling a cylinder. There is no such thing as a magic number that it a
go/no-go for doing a top.

- Mark

wrote:
All these replies and not one serious answer.

They were serious, now you ask the proper question.



Let me rephrase the question.

On the Big Lycoming engines, at what compression reading would indicate a
need for an investigation. In other words, what compression reading is
considered a warning sign?

It depends. If the reading isn't in the mid 70's or above on a
particular cylinder then find out where the air is escaping and fix
accordingly. If the reading was zero you still wouldn't necessarily
overhaul the engine.

Dear Mr. ygaabofm
Sorry we couldn't help you. Have you tried asking NASA?


" wrote in message
nk.net...
All these replies and not one serious answer.

Let me rephrase the question.

On the Big Lycoming engines, at what compression reading would indicate a
need for an investigation. In other words, what compression reading is
considered a warning sign?

ygaabofm


"kage" wrote in message
...

" wrote in message
ink.net...
On a Lycoming O-550, at what compression reading would you start to
consider
doing a top or complete overhaul?




There is no such engine.

KG

First of all, thank you for answering the question.

Secondly, the first answers were not serious because it was obvious from the
answers that they did understand the question, and chose not to answer it.
There were some pretty detailed answers but none gave at what reading would
one start considering the cylinder a problem.


"Newps" wrote in message
...


wrote:
All these replies and not one serious answer.

They were serious, now you ask the proper question.



Let me rephrase the question.

On the Big Lycoming engines, at what compression reading would indicate
a
need for an investigation. In other words, what compression reading is
considered a warning sign?

It depends. If the reading isn't in the mid 70's or above on a
particular cylinder then find out where the air is escaping and fix
accordingly. If the reading was zero you still wouldn't necessarily
overhaul the engine.

No. Have you tried posting something useful?


"Fly" wrote in message
...
Dear Mr. ygaabofm
Sorry we couldn't help you. Have you tried asking NASA?


" wrote in message
nk.net...
All these replies and not one serious answer.

Let me rephrase the question.

On the Big Lycoming engines, at what compression reading would indicate
a
need for an investigation. In other words, what compression reading is
considered a warning sign?

ygaabofm


"kage" wrote in message
...

" wrote in message
ink.net...
On a Lycoming O-550, at what compression reading would you start to
consider
doing a top or complete overhaul?




There is no such engine.

KG

wrote:
First of all, thank you for answering the question.

Secondly, the first answers were not serious because it was obvious from the
answers that they did understand the question, and chose not to answer it.
There were some pretty detailed answers but none gave at what reading would
one start considering the cylinder a problem.

You asked at what compression reading would you decide to overhaul the
engine. The answer is compression is just one factor. I had a cylinder
at one annual blow a 20/80. Doing an overhaul never entered my mind.
That cylinder turned out to be cracked. So you replace the cylinder and
move on. It's really only when your engine starts to make metal that
you contemplate overhaul. Although I had my engine make metal once,
turned out to be the shaft in my starter adapter. Replace the adapter
and the metal went away.