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

Peter Dohm wrote:


If you're buying three, your equipment probably dosn't have excessive
periods of inactivity. It's also good to hear that the recommended oil
additive has resolved any residual scuffing problems up until now.

Peter

They fly a lot, and that's what makes them last well. But we
still find water in the rocker covers after just a runup of about 10
minutes before inspection, even in summer weather. It's not there if
the airplane comes in after a flight, unless the weather was really
cold. We'll also often see water droplets on the oil dipstick.
On the other hand, in my old A-65 in my Jodel, I see corrosion
simply because it doesn't get flown much and when it does it's for
rather short flights. Too busy working on airplanes or with students to
find much time to play.

Dan

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

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.

The water in the oil will obviously evaporate at lower temperatures.
However, when you run the engine it puts combustion byproducts into the
crankcase. ( There is always a bit gets by those rather sloppy piston
rings. ) These byproducts are the oxidized or "burned" results of burning a
hydrocarbon fuel. Burnt hydrogen is H2O or water. Burnt carbon is CO or
CO2. These wind up in your oil as a result of running the engine. The
trick is to get the oil warm enough so that they evaporate away FASTER than
you add them into the mixture. Then you will get the water out of the oil
and avoid the formation of the organic acids that will cause corrosion
inside the engine. Minor surface corrosion that is irrelevant on the
outside of the engine may be much more serious on the inside. Yes, I have
overhauled more engines because of corrosion than because of wear.

Running the engine for a few minutes on the ground will add to the water and
other corrosives in the oil. Then you turn it off and let it work on the
guts of your engine. Do that if you want. I do overhauls quite
reasonably.

Running the engine for a longer time until the oil is warm enough to
evaporate off the water on the ground? That is not so good either. By the
time the oil is warm from ground running with most aircraft engines the
cylinder head temps are going off scale and you are beginning to cause other
problems from overheating. Look at all the guys shutting down from
overheating while waiting in line for takeoff at Oshkosh after the airshow!
:-)

If you go ahead and go flying, at least a little bit, you both warn and
distribute the oil and cool the engine. Why not go flying anyway. Isn't
that what you have the airplane for? :-)




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

See above.


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.

See above.


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.


You are wrong. Sorry.


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.


See above. Lucky lucky.


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.

Quite true. See above.


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.

Clearly you don't understand the difference between dirty oil and wet oil.
Just as combustion puts gobs of water into the oil, it also puts in some
soot, making the oil eventually turn black. Detergent oils also pick up
sludge and crud from within the engine and carry it around in suspension in
the oil. Good idea to dump it out and get a fresh start every once in a
while.
I recommend 25 hours without a filter and 50 hours with a filter.
Remember, oil is much cheaper than engines! :-)



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.


And some blockheads fly in the face of experience and proven test results.
Everything we know is NOT an OWT. Most OWT's are coming from people who
only THINK they know but have no scientific data to support their possibly
erroneous observation.

For example:

Cigarette smokers often get lung cancer.

Cigar smokers sometimes get lung cancer.

Pipe smokers rarely get lung cancer.

Cigarette smokers often use cigarette lighters.

Cigar smokers sometimes use cigarette lighters.

Pipe smokers usually use matches and rarely use cigarette lighters.

All smoke tobacco products.

Clearly the correlation with lung cancer is with cigarette lighters, and not
with tobacco products.

If we all used matches instead of cigarette lighters no one would get lung
cancer any more!

I love logic.

My kid brother was a statistician for the Navy before he retired. He had a
lovely comment about statistics.

"Most people use statistics like a drunk uses a lamp post. For support
instead of illumination!"

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )



Blue Skies
Rusty

"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 )

Water's vapor pressure rises with temperature, if you remember your
physics. Raising the vapor pressure drives it of sooner. It doesn't
have to boil. 180 is a recommendation. Below that, the water might form
in the case faster than it will evaporate, and you'll have increasing
amounts accumulating in the engine.

The research is there. Here are some who have experience in the
area:
http://www.sacskyranch.com/corrosion.htm

http://doc.tms.org/ezMerchant/prodtms.nsf/ProductLookupItemID/JOM-0505-54/$FILE/JOM-0505-54F.pdf?OpenElement

http://www.ramaircraft.com/Maintenan...mendations.htm

http://www.memagazine.org/backissues...italsigns.html

Lots more if you Google it.

Dan

I hope you're just baiting me on this one, but you've left the door too
wide open, and I have to go through it just once. I read all four of
the web sites that you posted, and frankly I don't really see where you
might think that any of them deal with the issue that I thought we were
talking about by giving specific data on a comparison basis. You know,
like stating the moisture content and acidity of sample A is such and
such and from sample B it is such and such. So I'll comment on them one
by one.

Sacramento sky ranch...... This page shows pictures of rusted (not
dissolved or corroded by acid) lifter faces and such and talks about
how important it is to guard against it and how quickly it can occur.
It gives the same advice that we have been talking about, the
importance of frequent flights, oil changes, etc. I don't see where it
gives a comparison of oil moisture content or acidity for oil sampled
from frequently flown aircraft versus that sampled from engines that
were only ground run. Do you? If so please tell me where. We all
understand that oil eventually drains off engine parts and the moisture
in the air will cause it to rust. I thought we were discussing whether
or not oil deposited from a ground run-up would protect the cam or
corrode it, right? Like I said, many places say that you must fly often
to evaporate the moisture, but samples from each with numbers showing
how much the moisture and acidity increases to detrimental levels when
you only ground run the engine have been hard to find.

Website #2.... This is an article where a comparison of the corrosion
resistance of two different magnesium alloys is presented. I think it
best to quote a part of the article here.
From the article:
"The internal corrosion response
concentrates solely on the behavior of the alloy within the coolant
circiut of the engine."

That's means they're looking at how a new alloy's corrosion
performance compares to an old one when exposed to anti-freeze. They
didn't even consider the oil circulating through the block. Probably
because they know it doesn't corrode things but protects them. I don't
see how they answered any of our questions. The cases on my Lyc are
made from A356 aluminum, and the cam and lifters from steel and iron.
The corrosion response of a magnesium alloy to anti-freeze relates to
the corrosive effect of oil from a ground run on a camshaft just how
Dan?

website #3....RAM Aircraft....This is just mostly the same stuff as
what was on the Sac sky ranch site. Mostly good advice, but certainly
nothing that demonstrates with scientific data that oil from a ground
run has such and such moisture content and PH level. They did however
demonstrate that knowledgeable people can have different opinions. From
the article,
[RAM service history records indicate that Mineral
Based AD oils perform significantly better than synthetic and
semi-synthetic oils.]

I see that you have had better results from Aeroshell Semi-Synthetic,
.

website #4....This article talks about new devices being developed that
are beginning to monitor in real time the chemical condition of the oil
in an engine. Didn't see data giving a comparison of the moisture
content or PH of frequently run oil versus that from a ground run here
either. Like I've said, maybe some people have done it, but I haven't
seen it published. These devices will sure make that possible though.
Maybe we will see something in the future! Yea!

I really don't think that anyone would think that those sites gave good
scientific data that supported the opinion that ground runs will
corrode your engine, but every year there are several forced landings
with fatalities, due to engine failure that would not have happened had
the engines not been allowed to rust. Maybe those engines would have
been saved had someone not been told to just let them sit if you can't
fly them. That is why I felt I should respond. After all, the ONLY
scientific data I have seen on the subject is my own oil analysis
results that told me there is 0.0% moisture in my oil sample.

I ground run maybe 6 or so times during the winter, in between flights
that is, and only when flying is not safe.

Blue skies,
Rusty

What sort of oil analysis service are you using? This outfit
here

http://www.oillab.com/oil.html

says that water is detected at levels of 1% or more using
the physical test, and most other contaminants using spectroscopic
analysis. My understanding of the spectroscopic test is that they burn
a small amount of the oil, run the light generated through a prism to
split it into its colors, and analyze the spectrum to get an idea of
the elements present. Water doesn't burn.
If they're not using the ASTM tests, your water content
numbers may be useless. 1% is a lot of water, and besides, much of the
water that may have been in your oil may have already turned to acids.
1% water in 6 quarts of oil is 2 ounces, a third of a coffee cup.
This argument could go on for a long time. It will someday
be settled when you finally get an overhaul and the technician reports
on what he finds. My experience, and the experience of many others, is
that condensation is real and it wrecks engines.

Dan

In article , "Highflyer" wrote:

The water in the oil will obviously evaporate at lower temperatures.
However, when you run the engine it puts combustion byproducts into the
crankcase. ( There is always a bit gets by those rather sloppy piston
rings. ) These byproducts are the oxidized or "burned" results of burning a
hydrocarbon fuel. Burnt hydrogen is H2O or water. Burnt carbon is CO or
CO2. These wind up in your oil as a result of running the engine. The
trick is to get the oil warm enough so that they evaporate away FASTER than
you add them into the mixture. Then you will get the water out of the oil
and avoid the formation of the organic acids that will cause corrosion
inside the engine. Minor surface corrosion that is irrelevant on the
outside of the engine may be much more serious on the inside. Yes, I have
overhauled more engines because of corrosion than because of wear.

Running the engine for a few minutes on the ground will add to the water and
other corrosives in the oil. Then you turn it off and let it work on the
guts of your engine. Do that if you want. I do overhauls quite
reasonably.

Running the engine for a longer time until the oil is warm enough to
evaporate off the water on the ground? That is not so good either. By the
time the oil is warm from ground running with most aircraft engines the
cylinder head temps are going off scale and you are beginning to cause other
problems from overheating. Look at all the guys shutting down from
overheating while waiting in line for takeoff at Oshkosh after the airshow!
:-)

If you go ahead and go flying, at least a little bit, you both warn and
distribute the oil and cool the engine. Why not go flying anyway. Isn't
that what you have the airplane for? :-)



If the goal is engine preservation without flying, what would you think of
using a pre-oiler (electric oil pump) to pressurize the oil system and then
pull the prop through several blades every couple of weeks?

Would that keep all the internal parts from corroding, or will some parts
remain dry if the engine does not turn at normal operating speeds?

who cares? wrote:

If the goal is engine preservation without flying, what would you think of
using a pre-oiler (electric oil pump) to pressurize the oil system and then
pull the prop through several blades every couple of weeks?

Would that keep all the internal parts from corroding, or will some parts
remain dry if the engine does not turn at normal operating speeds?

The cylinders won't get any oil. They rely on oil thrown off
the crank journals at idle speeds or better; some have a small hole in
the con rod to squirt oil across to the opposite cylinder, but that
hole has to be lined up with an oil gallery hole in the crank. When the
engine's running, it's a tiny squirt when the holes pass each other ,
and when the engine's off, the holes most likely aren't aligned and
won't do any good.
The inside of the case is coated with oil when the engine's
running. The cams get oil thrown at them while it's running. The gears
rely on rotation and drip for lube. Cranking the engine or pulling it
through by hand doesn't do a really good job of moving the oil around.

Dan

Hell I live in the Mojave desert. It isn't real dry here but you can win a
prize and a free medical exam if you can spit on the sidewalk here.

--
Kathy Fields
Experimental Helo magazine
P. O. Box 1585
Inyokern, CA 93527
(760) 377-4478
(760) 408-9747 general and layout cell
(760) 608-1299 technical and advertising cell

www.vkss.com
www.experimentalhelo.com


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

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

As I posted previously, I use Blackstone labs for my oil analysis,
which is a popular lab for GA pilots. They have stated many times that
there was no water or fuel found in my oil sample. I seriously doubt
that a trace amount of water in the oil would cause it to corrode metal
anyway, since it is still mostly oil which protects it.

Rusty


wrote:
What sort of oil analysis service are you using? This outfit
here

http://www.oillab.com/oil.html

says that water is detected at levels of 1% or more using
the physical test, and most other contaminants using spectroscopic
analysis. My understanding of the spectroscopic test is that they burn
a small amount of the oil, run the light generated through a prism to
split it into its colors, and analyze the spectrum to get an idea of
the elements present. Water doesn't burn.
If they're not using the ASTM tests, your water content
numbers may be useless. 1% is a lot of water, and besides, much of the
water that may have been in your oil may have already turned to acids.
1% water in 6 quarts of oil is 2 ounces, a third of a coffee cup.
This argument could go on for a long time. It will someday
be settled when you finally get an overhaul and the technician reports
on what he finds. My experience, and the experience of many others, is
that condensation is real and it wrecks engines.

Dan

On Mon, 24 Apr 2006 19:25:08 +0800, Stealth Pilot
wrote:

On Sun, 23 Apr 2006 22:45:06 -0400, "J.Kahn"
wrote:



You don't really need to fly it once a week. Once a month will do as
long as it gets an hour or so.

an hour or two *after* the engine temperature is at the normal running
temp range will see it right.

white oil? fill it up with avgas and fly out the tank in one
uninterrupted flight and it should be black again.

An hours flight will remove the water and I already use 100LL.

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


my aircraft occasionally sits for longer than I want and I find on a
long cross country that by the end of the second day's flying it is
running like a well oiled sewing machine again. flying for shorter
periods never seems to get the sewing machine effect where it runs
noticeably sweeter.

Stealth Pilot