I found this discussion very interesting and offer it for your
consideration. Almost everyone knows to keep oil over 170F..not hard to do
in a 13B.
Marc W.
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From: John Deakin <jdeakin@advancedpilot.com>
Subject: Water in the Oil?

Someone brought up the subject of water in the oil of a PowerTow device,
where the owner thought someone had sabotaged him by putting it there. Bob
Moseley jumped in and wrote the following, which looks good to us!

Yep, I do have an idea. The short time of operation and low power did it to
you. When I was with TCM, Pete Tannis (of Tannis heater fame) conducted a
test that I was involved in. He took a Piper Seneca and played with the oil
vernatherms (temperature control valves) so they would keep the oil
temperature at 160 degrees on one engine and 180 degrees on the other.

Fresh oil and filters were installed and the aircraft flown from their base
in Minnesota to Florida. A wide range of OAT was experienced on the flight.
Upon arrival, they carefully drained the oil and measured the amount of
water condensation in the oil. The engine run at 180 degrees had a slight
trace of moisture that was unmeasurable. The engine run at 160 degrees had
over 6 ounces of water in it.

This report was forwarded by me to TCM and became the subject of much
discussion related to oil temps, cam/lifter failures and other issues
related to rust. TCM has always preferred if possible to run oil temps
around 200 degrees to keep moisture boiled out as much as possible.

This test by very reputable people independent of TCM confirmed that oil
temperature is related to contamination by moisture due to normal combustion
blowby found in all piston engines. Normally, this is evaporated and
dispelled out the breather -- after the temperature is elevated enough to
boil it out. If the temperature is not high enough, it stays in the oil
inside the crankcase. Starting your PowerTow and running it long enough to
put away or take out your aircraft is creating a rust bucket. Not only are
you not creating enough temp to get rid of inherent moisture, you are
inducing more by the temp of the engine coming up some and then cooling off
and letting it set until????

Fact is, YOU were the likely saboteur and did not know it. Don't feel bad,
all of us are guilty of the same thing in our aircraft engines. It is pretty
well found in house discussions at TCM that to best rid the engine of
moisture condensed by previous flights or crash and dash practice, and
gathered inside the engine takes cruise temps and oil temps of 180 degrees
for an hour to best rid the oil of moisture contamination. Here is an
example that I ran into that rang very true of what I just said. This
happened just a short distance away from where I am right now. The aircraft
was kept inside of a hangar. It also sat very close to the Missouri
River....about 1/4 mile away, condensation in late evenings from natural
cooling is thought to be somewhat of a factor. An owner of a Piper Turbo
Arrow installed a new remanufactured engine in the month of January. He used
the aircraft as an instrument training aircraft and by September it only had
about 40 hours on it. A reason for recall by TCM was generated in house and
inspection of these types of engine was done in the field.

Upon removal of the accessory case, EXTREME rust was found on all of the
gears. The owner promptly accused TCM of assembling his engine with rusty
gears and wanted full warranty and replacement of the engine. I politely
informed him that TCM WILL NOT WARRANTY RUST and I was reasonably sure that
they did not assemble the engine with gears that had rust on them. I asked
him what his flight habits were. He stated that he took two long flights of
slightly over an hour and the rest of his flying was touch and goes for his
currency and student proficiency in the 40 hours accumulated since
installation 9 months earlier. OK, I said, what is your oil temp? Thinking
the right answer was, "Oh, it never got much off the peg," he confidently
stated that, thinking it to be a good answer. Uh-unh, he paid for several
thousand dollars of rusty gears after we had a little talk on what caused
the rust in the first place.

It is estimated that on a standard atmospheric day, 14 gallons of water is
vaporized and run through the engine for every one gallon of gas consumed.
This vapor is easily seen on any engine's exhaust on a cold day. A
percentage of that vapor is induced into the internal parts of the engine by
natural means of blow-by, consistent and linear with how much blow-by the
engine has. This will naturally be more when engines are cold until
operating temps are reached. Operating temps typically are not reached on
touch and go operations, even in warm OAT's. This will also greatly increase
the moisture content internally in the engine due to low temperatures and
water that is mixed with the oil along with very corrosive acids from
blow-by and causes cam/lifter failures, rust on all internal parts.

(Deakin note: We don't need to get the oil temp up to the boiling point of
water to get rid of it. Oil is spayed onto the bottoms of the pistons, where
the "sizzle factor" will vaporize any water. Also, the boiling temperature
drops with altitude, about 1 degree per thousand feet.)

Best...

John Deakin Advanced Pilot Seminars http://www.advancedpilot.com (Seminar
NOW ON-LINE!)