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

wrote:

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.

Keep in mind where most of the water is coming from, Rusty. Burning gas
produces carbon dioxide and .... WATER. Look at the tailpipes in winter
as you make your morning commute. You'll see water dripping from many
mufflers.

The one hour at 180 degree mark isn't magic. It's just a good point
where you can be sure that the engine has boiled off most of the water
that it collected while warming up. Also keep in mind that the oil is
trying to evaporate the water from an open pan. The engine is mostly
closed up and it has to circulate that oil through several times to get
all the water out (while more is being push back in).

--
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)."

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)."

Ernest,

I agree with alot of what you said. The point of my OP was not to
challenge what the best care of the engine is. I think we all agree
that flying it an hour a week is what is called for, along with regular
oil changes. What I has me concerned is that many times during the
winter, it is difficult if not impossible to do this. In that
situation, I think it is better to warm up the engine than just let it
sit. The cam and lifter on Lycomings will tolerate no rust at all. Once
you have even a small rust pit in the lifting face of the cam or lifter
I'm afraid you are looking at a tear down in the not too distant
future. Literally beats them to death in short order. And like I said,
my oil analysis results show no water at all, zero. As for the engine
making water, of course it does, and it goes right out the exhaust as
you said. I don't think the engine stays very cold for any length of
time once running. Those babies get hot, and quick, even in the winter.
I doubt if they collect much if any water during start up. I also don't
think the oil turns to an acid capable of dissolving the engine. I
could be wrong, as I haven't done the research, but then, I don't think
anyone else has either. Some say they have, but they aren't showing it
for us to see, at least not that I'm aware of. I realize that the 180
deg is probably meant as a guide, but they do state specifically that
if you don't hit 180, the water won't evaporate. I think this is
nonsense. The oil in a running engine is literally blown and slung
around like a hurricane. It doesn't just sit at the bottom of the sump.
And the volume of oil pumped is huge. 90 psi will do that. I think that
there probably are pockets within the engine that trap water. The front
of the hollow crank comes to mind, but I don't think they ever get
purged of their water, even after hours of operation.

Blue skies,
Rusty

#1 has been circulating for years in motorcycle banter. I've seen for myself that folks who only take short trips on their bikes get white dipsticks, from all the moisture in their oil.



-------------------------------------------------------------------

"Patriotism means to stand by the country. It does not mean to stand by the President."
- President Theodore Roosevelt

Ernest Christley wrote:

wrote:

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.

Keep in mind where most of the water is coming from, Rusty. Burning gas
produces carbon dioxide and .... WATER. Look at the tailpipes in winter
as you make your morning commute. You'll see water dripping from many
mufflers.

The one hour at 180 degree mark isn't magic. It's just a good point
where you can be sure that the engine has boiled off most of the water
that it collected while warming up. Also keep in mind that the oil is
trying to evaporate the water from an open pan. The engine is mostly
closed up and it has to circulate that oil through several times to get
all the water out (while more is being push back in).

--

Water boils off at 212.9 F ?

So operating at 180 oil temp removes water - how?
(Yeah, I know - s l o w l y)

That sounds a lot like "go fly it for an hour".
Obviously the best solution, but not always possible.


On the other hand...



Richard