Nasa Icing courses

Whenever I see less than 200 hours on an engine in a year, it seems like
there are tales of destruction of an engine to follow.

???

That describes almost every privately owned aircraft at our airport. Only
trainers routinely put on more than 200 hours per year.

Mary and I fly more than anyone at the airport, and we just barely put 200
hours on last year.

Really? I would have thought you put far more than that on, per year.

OK, then perhaps it is the frequency of being well warmed up that is the
more important factor. I have always read that the moisture that is the
killer, and when engines sit for more than a couple weeks, frequently, that
the rust begins killing the internals.

I wonder what the minimum time per year, and maximum frequency of running is
necessary to keep rust at bay?

Still, I think that only rollers touching the cams would be beneficial. I
wonder how many kits have been designed to retrofit popular lycosaruses?
--
Jim in NC

"Morgans" wrote in message
...

Whenever I see less than 200 hours on an engine in a year, it seems like
there are tales of destruction of an engine to follow.

???

That describes almost every privately owned aircraft at our airport.
Only trainers routinely put on more than 200 hours per year.

Mary and I fly more than anyone at the airport, and we just barely put
200 hours on last year.

Really? I would have thought you put far more than that on, per year.

OK, then perhaps it is the frequency of being well warmed up that is the
more important factor. I have always read that the moisture that is the
killer, and when engines sit for more than a couple weeks, frequently,
that the rust begins killing the internals.

I wonder what the minimum time per year, and maximum frequency of running
is necessary to keep rust at bay?

Still, I think that only rollers touching the cams would be beneficial. I
wonder how many kits have been designed to retrofit popular lycosaruses?
--
Jim in NC

I wonder if there is any statistical evidence on this issue regarding
incidences per region?

Are planes out here in the desert SW less prone to this?

Just wondering out loud...

Jay Beckman
PP-ASEL
AZ Cloudbusters
Chandler, AZ

I wonder if there is any statistical evidence on this issue regarding
incidences per region?

Are planes out here in the desert SW less prone to this?

Just wondering out loud...

That would be an interesting study. It might tell how much of a factor
condensation is.
--
Jim in NC

Jay Beckman wrote:
"Morgans" wrote in message
...

Whenever I see less than 200 hours on an engine in a year, it seems like
there are tales of destruction of an engine to follow.

???

That describes almost every privately owned aircraft at our airport.
Only trainers routinely put on more than 200 hours per year.

Mary and I fly more than anyone at the airport, and we just barely put
200 hours on last year.

Really? I would have thought you put far more than that on, per year.

OK, then perhaps it is the frequency of being well warmed up that is the
more important factor. I have always read that the moisture that is the
killer, and when engines sit for more than a couple weeks, frequently,
that the rust begins killing the internals.

I wonder what the minimum time per year, and maximum frequency of running
is necessary to keep rust at bay?

Still, I think that only rollers touching the cams would be beneficial. I
wonder how many kits have been designed to retrofit popular lycosaruses?
--
Jim in NC


I wonder if there is any statistical evidence on this issue regarding
incidences per region?

Are planes out here in the desert SW less prone to this?

Just wondering out loud...

Jay Beckman
PP-ASEL
AZ Cloudbusters
Chandler, AZ


Tanis has an article on engine corrosion
http://www.tanisaircraft.com/servicebullitens.html where they list a
bunch of factors leading to cam corrosion. If you go by that list, my
score comes out to 11 or 12 which they say makes my engine a candidate
for corrosion. The surprise to me was recent overhaul puts the engine
at risk. Digging into that more, it seems that a low time engine hasn't
had a chance to build up any varnish to protect surfaces. Now, I can't
see varnish building on the cam faces, so I don't entirely buy that.

The other surprise to me was that they claim multi-weight oil is bad for
corrosion resistance if the airplane is not flown very frequently (a
couple times a week) because it drains off too quickly. I vaguely
recall seeing a similar claim a while back.

So, I still don't know what caused my cam to fail, but articles like the
tanis one seem to indicate that even a relatively new cam can get rust
pits on the cam faces that can lead to an early demise.

They also advocate a engine ventilator to be used in conjunction with
full time preheat to dry out the crankcase. that's great if you can
leave it plugged in 24/7. I can't because I am in a group hangar where
the FBO regularly shuffles the aircraft around. I guess I'll switch
back to single weight oil and make it a point to fly at least once evey
7 days instead of at least once every 20 days like I had been doing.
Hopefully I'll avoid trashing another cam. In the mean time, I will be
trying to get a forensic analysis of the old cam to hopefully learn why
it failed.

I did see the cam lobe myself, and it was spalling rather profusely.
The adjacent lobes did not appear to have any pits or rough spots on them.

It seems to me that there ought to be a way to go in through the
dipstick with a filtered compressed air wand or something to fog oil in
the crankcase to get a pre-lube, as well as to periodically lube the
inside of the engine during a period of inactivity. Once the engine is
running there is plenty of oil flying around to keep everything lubed I
think, the problem is a dry start after a relatively short period of
inactivity, and a regular pre-oiler doesn't seem like it would get the
oil to the places it is really needed, ie the cam shaft, cylinder walls,
and accessory gears.

It seems to me that there ought to be a way to go in through the
dipstick with a filtered compressed air wand or something to fog oil in
the crankcase to get a pre-lube, as well as to periodically lube the
inside of the engine during a period of inactivity.

It would probably require the oil to be warm to atomize it. There is a
major baffle system in the crankcases that prevent the oil from being
sucked into the whirling machinery. That baffle system would tend to
defeat most attempts at atomization in the sump. It wouldn't take much
oil though to fog things enough to eventually get the insides of the
crankcase wet. I'd like to try it sometime to find out. Anyone want
to saw a hole in their crankcase?

I generally agree with Tanis on the importance of cold start preheat,
but my '75 C172M is now at 1700 TTSN & has never been apart.
Compression and oil consumption hasn't changed, & obviously it gets
flown infrequently. The last oil analysis was 5.8 PPM of iron. It
has a Tanis score of about 17. I only preheat the oil & use a blanket
on the engine.

The key, especially with Lycomings, is to NEVER do a cold start without
preheat below like 40 degrees - warmer if it has been sitting for some
weeks & warmer if you don't have winter oil, but otherwise keep it cold
if it is not being flown.

I now have started to shut off the fuel & run the carb empty if it
isn't going to be run for a week or more. I try to purge the engine of
combustion gasses & use autofuel almost exclusively. It really helps
restarting next time with autofuel.

Ray Andraka wrote

The other surprise to me was that they claim multi-weight oil is
bad for corrosion resistance if the airplane is not flown very
frequently (a couple times a week) because it drains off too
quickly. I vaguely recall seeing a similar claim a while back.

Ray, do a search on the Lyc o-320H engine. The "H" engine had a real
bad habit of cam failure until the FAA put out an AD mandating that a
particular additive be used in the oil. This seemed to fix the
problem, I taught in one particular 172N for six years with never a
problem. The additive was so good, that it is now a standard
ingredient of the AeroShell multigrade oil. I see this "snake oil"
being sold over the counter at Sun n Fun, but the name escapes me
right now. I would't switch if I were you.

Bob Moore

Mary and I fly more than anyone at the airport, and we just barely put
200 hours on last year.

Really? I would have thought you put far more than that on, per year.

200 hours per year is a LOT of flying, if you're not either (a) retired, or
(b) getting paid to do it.

It's the equivalent of flying from Iowa to Michigan -- and back -- every
week.

Or, put another way, it's four 1-hour hamburger flights per week, every
week, all year long...
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

On Sun, 08 Jan 2006 13:45:12 GMT, Jay Honeck wrote:

Or, put another way, it's four 1-hour hamburger flights per week, every
week, all year long...

Is this slightly low Jay? 1/2 hour each way? My hamburger runs are
minimum 1 hour each way, which would reduce it to 2 hamburger flights per
week.

You are right, 200 hours a year is an awful lot of flying. You had me
curious for me, how much in a year I fly, and it was as follows:

2001 11.7
2002 49.5
2003 142.2
2004 192.9
2005 126.4
2006 4.0

I try to fly once a week at minimum myself and no less then one hour air
time when I fly.

I was told ground runs is one of the worst things you can do to an airplane
engine, as it was designed for sustained high RPM operations, not ground
run RPMS.

Allen

It is to do with air flow, you don't get proper cooling and
crankcase ventilation is very poor on the ground.

After landing, cool down is as important as warm up,
particularly with a turbocharged engine.


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

--
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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.


"A Lieberman" wrote in message
...
| On Sun, 08 Jan 2006 13:45:12 GMT, Jay Honeck wrote:
|
| Or, put another way, it's four 1-hour hamburger flights
per week, every
| week, all year long...
|
| Is this slightly low Jay? 1/2 hour each way? My
hamburger runs are
| minimum 1 hour each way, which would reduce it to 2
hamburger flights per
| week.
|
| You are right, 200 hours a year is an awful lot of flying.
You had me
| curious for me, how much in a year I fly, and it was as
follows:
|
| 2001 11.7
| 2002 49.5
| 2003 142.2
| 2004 192.9
| 2005 126.4
| 2006 4.0
|
| I try to fly once a week at minimum myself and no less
then one hour air
| time when I fly.
|
| I was told ground runs is one of the worst things you can
do to an airplane
| engine, as it was designed for sustained high RPM
operations, not ground
| run RPMS.
|
| Allen

I was told ground runs is one of the worst things you can do to an airplane
engine, as it was designed for sustained high RPM operations, not ground
run RPMS.

You know, I've heard that since Day One of ownership, too, but ya just
gotta wonder if it's not yet another "old wive's tale", like so many of
these "tried and true" things. How does the engine know the
difference between ground runs at, say 2000 RPM (run-up speed on our
plane) and an extended descent? Is *that* "bad" for the engine, too?

Doesn't running it for 30 minutes on the ground circulate the oil, and
prevent corrosion? Can't you get oil temps up to 150 or better (I
know, 180 is optimal, but...) with a ground run? Isn't that better
than letting it sit and rot till spring?

I fly too often for this to really matter, but I always wonder if it's
a real issue or not? Kinda like "shock cooling" and "pulling the prop
through" before starting on a cold day... And Marvel Mystery oil,
while we're at it...

:-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"