Nasa Icing courses

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
|
|

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...."

Well, I am blessed to have an A&P who:

1. Doesn't work on little planes cuz he needs the money.
2. Is an award-winning home builder
3. Has 40 years in the business
4. Is an accomplished pilot
5. Has rebuilt over 100 O-540s, including mine.

What he says about engines is, in my world, gospel.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Stan Prevost wrote:
"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.

The mixture on injected engines typically is not as rich at idle as carburetted
engines, so the rpm increase should not be as great.

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

"Jay Honeck" wrote in message
news:Hxkwf.474673$084.253721@attbi_s22...

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?


Your O-540 is probably better at oil distribution than my O-235. Your
engine is substantially larger and more expensive. They can afford to give
it a better oiling system than exists in a smaller, cheaper engine.

As for trusting Lycoming to tell us: I believe they have a commitment to
safety, but they also make money from parts, like cam shafts. Adding to
that, summer is much different than winter oil at startup, not to mention
cylinder clearances. On startup, do you want the cylinders to wear out
faster, or would you rather protect your cam? You may not be able to have
both in an optimum fashion on some engines. Less RPM may help the
cylinders, but leave the cam with less lubrication. It makes me wish that
all cams had a direct spray oil system, and that there was an electric oil
pump that could be used to lubricate the engine prior to startup.

Paul Missman