IO-540 Rust

[zuelke]

My wife was taking a pinch hitter course and stood on the brakes too hard on a landing and dug one blade of the prop into the mud of the strip. Engine now at PennYan Aero. They discovered no damage from prop strike but heavy rust on cam and on cylinder walls below rings. Engine cannot be put back together as it is so I am spending a lot of $ to nickel plate and flow match the cylinders before they return the engine to me.

This plane is in a dry heated hangar - every night. I bought it new in Jan 2005 and have flown it 250 hours a year since (there is 750 hours on engine since new). Maintenance has been perfect. Compression is (was) 76-78/80 on all cylinders.

Where did this rust come from?? Some tell me Maule did not store the engine correctly before they installed it in my aircraft. Others say my chronic low oil temperature (165-170 degrees even with the oil cooler 80% closed off) caused the problem. Lycoming says 165 degrees is OK and could not be the problem. Still others say it is a routine Lycoming problem??? I'm looking for more opinions. I don't want to have an almost new engine destroyed in another 750 hours due to rust.

Anybody have a thought?

[flyer]

zuelke

It sounds like you have done everything correctly. It should not have that much rust. There must be something else going on. Did you personally see the rust?

flyer

[zuelke]

PennYan sent me a number of photos that clearly show lots of rust on the cylinders and cam.

[210TC]

Did the pictures show rust in the ring travel area? I have seen perfect cylinders with rust below the ring contact area. This will not effect the performance of the cylinder.
Lycoming should be held accountable for the cam problem. They have always been aware of this issue and have failed to correct it.

[montana maule]

After every flight before I push back in the hangar I pull out the dip stick and leave it out. You can watch the steam rise from the oil tube, even in the summer when I have 200 degree oil temps. Can't say it is a cure but letting all that moisture out can't hurt anything. If left inside it will condense when the engine cools.

What type of oil are you using? Aviation Consumer had a good article on oil and rusting a couple of months back.

[210TC]

This is one of the reasons I do not use differential compression testing.
The ONLY way to obtain a correct reading is to cycle the cylinder. Any problem effecting the rings will show up.
Differential will only give a reading at TDC (top dead center) the least likely place to lose compression.
This is why no body else on earth uses DCTesting. It was a good idea with the big radials. And many times if an exhaust valve was leaking one could hand lap the valve "in place" never removing the cylinder.
If you have an old faa manual it will note NOT to use DCtesting unless you have a low cylinder and want to know which direction the exhaust gases are running (out the exhaust port or into the crank case).

[zuelke]

I have a number of quite good photos of the cylinders and cam I can email if you will send me an email address. I'm in Pony, Montana at paul@zuelke.com

[flyer]

Zuelke

Your plane/engine are only 3 years old with consistant flying time. Most of our engines are much older with a lot less consistant flying. It does not make sense to me that your engine has more rust than ours. How long does it sit during the winter?

flyer

[zuelke]

since the day this plane was new, three years ago, it has rarely gone more than one week without flying and has never gone more than two weeks. When the plane does fly, I can count on one hand the number of times the plane has flown less than one hour at a time.

[a64pilot]

I won't say it wasn't improperly stored, but 99% of the time improper storage shows up with rust in the upper part of the cylinder wall between a piston and whatever valve that is open at the time allowing ambient air into the cylinder, not rust forming inside of the crankcase.
Without knowing much else, I would have to say the culprit is moisture forming inside of the crankcase, one very possible way is cold oil, short flights and not frequent enough oil changes.
I would install a digital, accurate oil temp gauge in the same galley as the factory one and do whatever is necessary to ensure my oil temp ran at least 180. The factory gauges are only good for seeing trends, not for knowing real temps.
Exxon elite claims to be real good at corrosion prevention, I'm using it for that reason. I don't know if there is anything to their claim, or if it's just propaganda.
I think the 165 claim for oil temp is real cold, as in Alaska in winter type temps.

[a64pilot]

Do you have an engine pre-heater?

[zuelke]

I have an EDM 800 and have had the probe out and tested it for accuracy. I have done the same for the analog panel gauge. Both are very accurate and the EDM shows 165 degrees to 175 degrees.

I do not have an engine pre-heater but since the airplane is kept in a heated hangar with the humidity inside the hangar extremely dry (typically below 35% (I'm in Montana at an elevation of 4100')) I have never felt that an engine heater would be of any value.

[flyer]

Jeremy

What do you think of a 3 year old Maule having this much rust when it appears to have been very well taken care of and flown often?

What Lycoming engine is it? Can you post the pictures on this website?

flyer

[210TC]

This appears way outside of the norm. It is possible this engine had a problem from the factory.
When you do everything by the book and this happens, something is wrong.
A letter should be sent to lycoming with all details.
If this happened to me I would ask for lycoming to fix the problem. If they refused I would prepare a comlplaint for a jury trial, unless I was in a state that had an acceptable amount that could be won in small claims.
Warrantees of merchantability or "implied warranty" something is defective or "not as expected' by a reasonable person, with reasonable care.
You have an expressed warranty which has expired. However, an implied warranty should clearly cover your situation. An implied warranty can go on for many years past the normal warrantees.

My three cents worth

[flyer]

I would also be questioning Maule. They should have an interest in finding out what went wrong. It reflects on the longevity of their aircraft.
I think this requires more investigating. How much did that aircraft cost?

flyer