Nasa Icing courses

The oil film, when all goes well, prevents actual metal to metal contact.
Just like the plain bearings on the crankshaft.


I had to have my engine (Lycoming O-235) overhauled last year at less than
1/2 TBO, partially for cam pitting. Prior to my owning it, it hadn't flown
too much for the past few years.

Now, I'm flying every 2 weeks, at least, if weather permits, and am using
Avblend. This additive is supposed to better impregnate the metal, and
prevent some of this corrosion.

I now have the plane in a hanger, instead of outside in the cold and added
moisture.


The few things I've heard about causing the problems a

Flying too infrequently, with oil seeping off the cam and moisture eating at
the exposed surfaces.

When flying happens, not getting the oil completely hot, so as to eliminate
the moisture from it.

Running the engine too slow at startup. Apparently, the cams in some
engines get lubrication mainly from the oil splashing around inside the
case. In some engines, 1000 RPM may not be sufficient for full lubrication
after startup. My A&P suggested 1100 - 1200 RPM.


I'm certainly hoping that the steps I'm taking will keep the engine in good
shape. I can't afford another overhaul anytime soon.

Paul Missman

"Paul Missman" wrote in message
...

....
The few things I've heard about causing the problems a

Flying too infrequently, with oil seeping off the cam and moisture eating
at the exposed surfaces.

When flying happens, not getting the oil completely hot, so as to
eliminate the moisture from it.

That's one thing that could be changed on aircraft engines that would give a
LOT of bang for the buck - positive crankcase ventilation. Huge reduction in
unburned hydrocarbons (you may or may not care about that), and a lot less
moisture in the crankcase - engines last a lot longer.

The straight up auto style PCV valve probably wouldn't be the way to go,
though. It won't get you much at higher altitudes where you have the
throttle wide open.

Running the engine too slow at startup. Apparently, the cams in some
engines get lubrication mainly from the oil splashing around inside the
case. In some engines, 1000 RPM may not be sufficient for full
lubrication after startup. My A&P suggested 1100 - 1200 RPM.

Anything's possible.


--
Geoff
the sea hawk at wow way d0t com
remove spaces and make the obvious substitutions to reply by mail
Spell checking is left as an excercise for the reader.

David Lesher wrote:

Saw a show w/ a Japanese craftsman making a sword. Two layers of
different steels. Pounded it thin; folded it over; pounded...
Many layers later, that was the sword...

Yep, that's a very old technique. Westerners call it "Damascus steel."

George Patterson
Coffee is only a way of stealing time that should by rights belong to
your slightly older self.

Jay Honeck wrote:

Some, however, like Ray's engine, do -- and in very peculiar ways. (Just
ONE cam lobe went bad?)

Why?

Once again. When the layer of hardened steel wears through, the rest of the lobe
wears *very quickly*.

George Patterson
Coffee is only a way of stealing time that should by rights belong to
your slightly older self.

George Patterson wrote:
David Lesher wrote:
Saw a show w/ a Japanese craftsman making a sword. Two layers of
different steels. Pounded it thin; folded it over; pounded...
Many layers later, that was the sword...

Yep, that's a very old technique. Westerners call it "Damascus steel."

Got a knife made using that technique. Beautiful grain, sort of like a
nice gun stock made with multiple layers of different wood, beautiful
when carved.

The Monk

Running the engine too slow at startup. Apparently, the cams in some
engines get lubrication mainly from the oil splashing around inside the
case. In some engines, 1000 RPM may not be sufficient for full
lubrication after startup. My A&P suggested 1100 - 1200 RPM.

Isn't that a stitch? Your A&P says 1000 RPM is too *slow* for proper
lubrication. Jim Macklin (and many others) says it may be too *fast* to
run your engine before proper lubrication has occurred. Who is right?

And my A&P says 1000 RPM or slower, primarily to save your prop on loose
rocks but also to ensure long engine life.

Argh. Wouldn't you think there would be SOME science to this?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Jim Macklin" wrote in message
news:Wgcwf.40975$QW2.5751@dukeread08...
point and then pull the mixture to shut it down. That
should show a slight 25-50 rpm increase just as it shuts
down since idle should be a little rich.


For my TIO540-S1AD, Lycoming says five rpm, not more than ten.

Stan

"Happy Dog" wrote in message
...

I've gone through a couple on one engine and they had those exact
symptoms. One AME suggested that the front lobes wear more quickly since
the cam is slightly elevated at the front so the oil drains off more
quickly. There are as many theories as worn cams, it sometimes seems.


Especially when you take your engine to your flight physical! :-)

Jay Honeck wrote:

Argh. Wouldn't you think there would be SOME science to this?

If there is, it's available from Lycoming or Continental for your engine. Not
from "my A&P says...."

George Patterson
Coffee is only a way of stealing time that should by rights belong to
your slightly older self.

I'll buy that, always best to use specific data rather than
a generic answer. It takes a pretty good eye and tach to
see 5 rpm.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"Stan Prevost" wrote in message
...
|
| "Jim Macklin" wrote
in message
| news:Wgcwf.40975$QW2.5751@dukeread08...
| point and then pull the mixture to shut it down. That
| should show a slight 25-50 rpm increase just as it shuts
| down since idle should be a little rich.
|
|
| For my TIO540-S1AD, Lycoming says five rpm, not more than
ten.
|
| Stan
|
|