Water in our oil, or just alot of hot air?

I just watched a program about the huge Oresund bridge between Denmark
and Sweden, and there was a segment about how the corrosion problem for

the bridge was dealt with. Instead of painting, they use sealed
compartments that have the air humidity kept below 60%. This they said
eliminates corrosion. This started me thinking about the corrosion we
aircraft owners are told to guard against, since I have personally been

told by an overhaul shop, that half of all the engines he sees that
need work, need it because of corrosion. There are several "facts" that

I am beginning to question as to their validity. The ones that come to
mind a

1) You have to get the oil up to 180 deg F or the water in the oil
won't evaporate.


2) Starting and ground running the engine for a minute or so is the
"worst" thing you can possibly do.


3) Flying for an hour will "clean" the oil (or at least evaporate the
water, preventing acid formation) so that it doesn't turn to acid and
dissolve the engine while sitting idle.


There are probably some others, but these three stand out the most

to me. Now I am sure that what I am about to say will not go over well
with some people, but I have the asbestos suit ready and waiting.
My take is that these three "facts" are a bunch of poppycock. Why

or how they got started is anyone's guess, but the reasoning behind
some of them is understandable, for others I wonder what they were
smoking at the time. My thoughts are along these lines, and I admit I
could be wrong, but I don't think so.


Concerning fact #1...Why does someone think that the water has to be
brought to a boil before it will evaporate. Water evaporates very well
even at sub-freezing temperatures,much less at the warm to hot temps
created in a running engine. And at say 140 F, I can't help but believe

that any water or moisture in the engine will be purged quickly. With
water at that temp you can literally see clouds of vapor escaping, and
this is well below boiling. Not that the hotter the engine gets the
water doesn't evaporate more quickly, it does I'm sure. It's just that
in the engine cases which are open to the air at the breather tube and
elsewhere, any heat above say 85 F or so will be more that enough to
dry out the oil in the crankcase. As evidence of this, I ground run my
engine all the time and have for many years. I live in a VERY humid
climate. The oil analysis reports I have done on a regular basis by
Blackstone have never shown any trace of water or moisture. I recently
tore done the engine for rebuild after more then 15 years of perfect
service, and the cam lobes, lifter faces, and every part in the engine
was shiny and totally free from rust or any other corrosion.


Concerning fact #2.... We all constantly clean and oil many of the
things we own such as tools, etc. It is the layer of oil that prevents
the rust. I accept that if the oil is too acidic it could corrode or
"chem mill" the metal, but it takes highly acidic liquid to do that,
and the oils I use have acid buffers in them to deal with mild acidity.



Running is the only way to re-oil all the parts in the engine,
especially the cam and lifters. Just like oiling the machinists tools
that I own keeps them rust free, oiling the engine keeps it rust free I

would think.


Concerning fact #3.... This is the one that really makes me wonder. If
oil needs to be changed every 25-50 hours, how does flying for an hour
clean it? I can't help but think that the longer the oil is used the
dirtier it gets. I guess they think that it's "really" dirty just after

starting, and you "clean" it as you fly.


In closing, it seems to me that many of the things we are told are
contradictory on this subject. I have witnessed many OWT come and go in

my time, so common knowledge isn't always correct. Lean of peak
operation comes to mind. Some blockheads still don't think George Braly

has it right.


Blue Skies
Rusty

wrote in message
oups.com...
I just watched a program about the huge Oresund bridge between Denmark
and Sweden, and there was a segment about how the corrosion problem for

Since you made the exact same post to R.A.Owining and RA.Piloting earlier
this week, is there something you're fishing for that didn't come out in
those discussions?

KB


Blue Skies
Rusty

Kyle,

If by "earlier in the week" you mean last night when I first posted,
versus this morning after I had done some Sat morning errands and prior
to reading any of the responses, then, no, I wasn't "fishing" for
anything. I was just trying to start a discussion about engine
corrosion that I think needs to be addressed with as many pilots as
possible. Is that all it takes to elict a snide remark from you,
posting the same question to different groups a few hours apart?

Blue skies,
Rusty

wrote in message
oups.com...
Kyle,

If by "earlier in the week" you mean last night when I first posted,
versus this morning after I had done some Sat morning errands and prior
to reading any of the responses, then, no, I wasn't "fishing" for
anything. I was just trying to start a discussion about engine
corrosion that I think needs to be addressed with as many pilots as
possible. Is that all it takes to elict a snide remark from you,
posting the same question to different groups a few hours apart?

Blue skies,
Rusty

Not trying to tick you off, just seeking clarification.

KB

I just watched a program about the huge Oresund bridge between Denmark
and Sweden, and there was a segment about how the corrosion problem for

the bridge was dealt with. Instead of painting, they use sealed
compartments that have the air humidity kept below 60%. This they said
eliminates corrosion. This started me thinking about the corrosion we
aircraft owners are told to guard against, since I have personally been

told by an overhaul shop, that half of all the engines he sees that
need work, need it because of corrosion. There are several "facts" that

I am beginning to question as to their validity. The ones that come to
mind a

1) You have to get the oil up to 180 deg F or the water in the oil
won't evaporate.


2) Starting and ground running the engine for a minute or so is the
"worst" thing you can possibly do.


3) Flying for an hour will "clean" the oil (or at least evaporate the
water, preventing acid formation) so that it doesn't turn to acid and
dissolve the engine while sitting idle.


----------------snip-----------

Blue Skies
Rusty

1) In automobiles years ago, the standard assertion was that you had to
get the engine temp up to 160 degrees for the water to evaporate from the
oil. As it happened, that was actually measuring water temp. 160 degrees
was simply the most common coolant thermostat temperature in those days. So
if the same jack asses are still breathing in and out, they are probably
claiming that 205 degrees is mandatory today.
About all I know for sure about water water condensing into much of
anything is:
a) it almost never happens inside a garage or hangar,
b) an engine covered with plastic and sitting on the ground will
accumulate MASSIVE amounts of water,
c) a small light object such as a medicine vial with a snap type lid will
accumulate water outdoors in the shade--such as under a patio roof.
As to evaporation, warmer is faster; but if the ambient humidity is
100%, a surprisingly small temperature rise (10 or 20 degrees IIRC) above
ambient will bring the relative humidity inside the engine below 50%.
2) I am not an aircraft and engine mechanic. However, I am confident
that running a Lycoming engine to circulate the oil is FAR BETTER than
letting it stand; both for the cylinders and the famous cam and tappets.
If I owned it and was not flying at least weekly, you're damned
right I'd ground run it! Not very long, but enough to circulate the oil and
at least get the temp needle off the peg. If, for any reason I was unable
to run the engine frequently, I would certainly place dessicant packages in
the intake(s), exhaust(s), and crankcase breather.
3) Yep, I agree that's an old mechanics tales as well. OTOH, any reason
to fly might bew a good reason.

As to the bridge, apparently the Danes and Sweedes haven't shelled one
another across the straights for so long they've forgotten about that. ;-)
In any case, small amounts of surface rust are trivial for a structure like
a bridge; but seriously debilitating inside an engine!

Peter

Peter Dohm wrote:
2) I am not an aircraft and engine mechanic. However, I am confident
that running a Lycoming engine to circulate the oil is FAR BETTER than
letting it stand; both for the cylinders and the famous cam and tappets.

You'd be wrong. With a couple minutes running you've just barely got
the thing warmed up (depending on climate). There's a lot of cold metal
in there to begin with. You first start the engine. Fuel burns to
produce CO2 and H20. Lots of it. A lot of that H20 will liquify when it
hits that cold metal, and get swept away into that cold oil. There is
will stay, reacting with other combustion byproducts to form weak
organic acids. They don't eat metal fast, but they do it as long as
they're there.

If you're going to do ground runs, run the engine to circulate HOT oil
for a couple of minutes. You'll be fine then (I think 8*).


--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

On Sun, 23 Apr 2006 00:24:07 -0400, "Peter Dohm"
wrote:

I just watched a program about the huge Oresund bridge between Denmark
and Sweden, and there was a segment about how the corrosion problem for

the bridge was dealt with. Instead of painting, they use sealed
compartments that have the air humidity kept below 60%. This they said
eliminates corrosion. This started me thinking about the corrosion we
aircraft owners are told to guard against, since I have personally been

told by an overhaul shop, that half of all the engines he sees that
need work, need it because of corrosion. There are several "facts" that

I am beginning to question as to their validity. The ones that come to
mind a

1) You have to get the oil up to 180 deg F or the water in the oil
won't evaporate.


2) Starting and ground running the engine for a minute or so is the
"worst" thing you can possibly do.


3) Flying for an hour will "clean" the oil (or at least evaporate the
water, preventing acid formation) so that it doesn't turn to acid and
dissolve the engine while sitting idle.


----------------snip-----------

Blue Skies
Rusty

1) In automobiles years ago, the standard assertion was that you had to
get the engine temp up to 160 degrees for the water to evaporate from the
oil. As it happened, that was actually measuring water temp. 160 degrees
was simply the most common coolant thermostat temperature in those days. So
if the same jack asses are still breathing in and out, they are probably
claiming that 205 degrees is mandatory today.
About all I know for sure about water water condensing into much of
anything is:
a) it almost never happens inside a garage or hangar,

We must live in different climates.
Here in Central Michigan it's not unusual to find the airplane
"dripping" wet with temperature changes.

I have an garage attached to the house. It's not unusual to find the
cars sweating with temperature and humidity changes. I had to work on
the garden tractor today and the engine is wet from the humidity and
temperature changes. (It's been 100% since last night and rained most
of the day.

Current temp is 50F) The weather for the area says 85% but it's
raining with light fog. Of course the briefing I printed out at 3:00
AM says visibility 6, 5000 sct, 10,000 bkn with temp 4 in light rain
and thunderstorms with 5,000 sct.
It's now starting to clear from the west and MOP is showing Vis 10,
1000 sct, 1500 bkn. Most of the afternoon was 1 and 500.

b) an engine covered with plastic and sitting on the ground will
accumulate MASSIVE amounts of water,

We get the same thing in our hangars on the airplanes and engines.
If I went out to the hangar today I'd find the plane dripping. The
temp is dropping slowly. It'll be near the upper 30's tonight.
Opening the cowl would find water droplets on the cylinders and
crankcase.

This is in a well ventilated metal hangar with a concrete floor.

c) a small light object such as a medicine vial with a snap type lid will
accumulate water outdoors in the shade--such as under a patio roof.
As to evaporation, warmer is faster; but if the ambient humidity is
100%, a surprisingly small temperature rise (10 or 20 degrees IIRC) above
ambient will bring the relative humidity inside the engine below 50%.

Also the engine breathes in and out with temperature changes. So
cooling not only raised the relative humidity inside, it brings in
more cool, damp air.

2) I am not an aircraft and engine mechanic. However, I am confident
that running a Lycoming engine to circulate the oil is FAR BETTER than
letting it stand; both for the cylinders and the famous cam and tappets.

If it's going to set long it needs to be protected not ground run
according to the engine manufacturers literature.

If I owned it and was not flying at least weekly, you're damned
right I'd ground run it! Not very long, but enough to circulate the oil and

If you are going to ground run it you want to bring it up to operating
temp. It's the short runs that not only don't evaporate much of
anything they put a lot more *stuff* into the oil as the cold engine
isn't running as efficient as a warm one and the byproducts can
condense inside.

Find a good clean spot on the ramp, let the engine warm up normally.
Then stand on the brakes and wind 'er up for a prolonged run. Of
course then makes the neighbors unhappy.

at least get the temp needle off the peg. If, for any reason I was unable
to run the engine frequently, I would certainly place dessicant packages in
the intake(s), exhaust(s), and crankcase breather.

They usually put desiccants in the plugs and plug off the intake,
exhaust and breathers.

Go into Pioneer Airport and look at the antiques that have the engines
preserved. I've forgotten the term, but at any rate each prop has a
note on it that says "Do not turn prop. Engine has been preserved".

3) Yep, I agree that's an old mechanics tales as well. OTOH, any reason
to fly might bew a good reason.

Might be but both Lycombing and Continental subscribe to it.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

As to the bridge, apparently the Danes and Sweedes haven't shelled one
another across the straights for so long they've forgotten about that. ;-)
In any case, small amounts of surface rust are trivial for a structure like
a bridge; but seriously debilitating inside an engine!

Peter

"Roger" wrote

We must live in different climates.
Here in Central Michigan it's not unusual to find the airplane
"dripping" wet with temperature changes.

I have an garage attached to the house. It's not unusual to find the
cars sweating with temperature and humidity changes. I had to work on
the garden tractor today and the engine is wet from the humidity and
temperature changes. (It's been 100% since last night and rained most
of the day.

I feel your pain! g

NC is like that, at times, also.

Want a good piece of advise? Insulate your garage, put up good insulated
garage doors, and with good seals installed. Run one 8" duct into the
garage from your central heat and air. It makes a huge difference at not
all that much expense.
--
Jim in NC

"Morgans" wrote in message
...

"Roger" wrote

We must live in different climates.
Here in Central Michigan it's not unusual to find the airplane
"dripping" wet with temperature changes.

I have an garage attached to the house. It's not unusual to find the
cars sweating with temperature and humidity changes. I had to work on
the garden tractor today and the engine is wet from the humidity and
temperature changes. (It's been 100% since last night and rained most
of the day.

I feel your pain! g

NC is like that, at times, also.

Want a good piece of advise? Insulate your garage, put up good insulated
garage doors, and with good seals installed. Run one 8" duct into the
garage from your central heat and air. It makes a huge difference at not
all that much expense.
--
Jim in NC

I am currently in Florida. However, I'll keep your solution in mind in case
of a move to a cooler climate.

Thanks for the advice.
Peter

"Peter Dohm" wrote in message
. ..
"Morgans" wrote in message
...

"Roger" wrote

We must live in different climates.
Here in Central Michigan it's not unusual to find the airplane
"dripping" wet with temperature changes.

I have an garage attached to the house. It's not unusual to find the
cars sweating with temperature and humidity changes. I had to work on
the garden tractor today and the engine is wet from the humidity and
temperature changes. (It's been 100% since last night and rained most
of the day.

I feel your pain! g

NC is like that, at times, also.

Want a good piece of advise? Insulate your garage, put up good insulated
garage doors, and with good seals installed. Run one 8" duct into the
garage from your central heat and air. It makes a huge difference at not
all that much expense.
--
Jim in NC

I am currently in Florida. However, I'll keep your solution in mind in
case
of a move to a cooler climate.

Thanks for the advice.
Peter


I frequently recommend storing airplanes in these warm humid climates in
"Planeports" rather than hangars. You have to keep the sun off to prevent
damage from the UV radiation. Letting the air blow freely through seems to
prevent the dew inside phenomena. In closed hangars I have seen it actually
raining inside the hangar when it was a clear night outside!

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )