Oil Sump / Oil Pan Repairs

[GAHorn]

This thread was split from the TradeMart, where Sybil Bartone posted a "wanted" ad for an oil sump. The following discussion inadvertently "hijacked" her original request, which can be viewed at:
http://www.cessna170.org/phpBB2/viewtopic.php?t=3737

Sybil-
You didn't mention if you had one that needs repair or if you just need one outright. Okanagan Aero Engines 250-765-9718 just weld repaired one for me and did a great job. I would recommend them.

It is important to send them an oil pan that has not already had a repair attempt made on it. If it has previously been welded on they may not accept it for repair. A local weld repair shop here in Anchorage thought they could repair another one but so far have not been able to weld the old magnesium casting without having it crack.
Richard

Richard, unless I was misinformed, Okanagan doesn't believe in weld repairs. They use epoxy as a filler in the corroded areas. At least that's what they did to the one they showed me.

[jrenwick]

It seems to me that an epoxy repair would have to expand and contract with temperature changes the same as the magnesium it was bonded to, or at least remain flexible enough to move with it, in order to maintain its bond to the metal. I don't know if this is possible -- I've only seen one example of an epoxy-filled oil pan, and in this case the bond didn't last.

John

[Bruce Fenstermacher]

George you are correct. Okanagan uses an epoxy and they have an approval to do so. They can't fix a pan that you can drive a truck through but a small pin hole is doable.

[Indopilot]

The last one we had repaired was done by Drake Air. It was a welded repair that looked pretty nice for a repair. Last I knew it was still going strong. Didn't even spring a leak when the hanger blew down on the airplane Not sure how but the only damage was to the rudder and wing leading edges. Brian

[GAHorn]

One of the little-appreciated fact about this sump/oil pan is that it is a stressed part. Otherwise, it'd make a good candidate for a sheet-metal replacement part.
George

[hilltop170]

George-
You are right! Again!

I just got off the phone with Fred at Okanagan Aero Engines (O.A.E.) about their sump repair. It is an epoxy repair, not a fusion weld. According to O.A.E., they have been doing them for 5 or 6 years now and some have already gone to TBO and come back for overhaul again. The sump repairs have lasted and did not have to be redone. The only times the repairs have had problems is when it has looked like sombody, maybe the mechanic, has picked at the repair with some sort of tool to see what is in there. Even then they can be re-repaired. Otherwise they last, according to O.A.E.

They start by water/bead blasting the corroded/leak area to clean it up. No grinding tools or chemicals are used which could contaminate the repair area. The epoxy is applied and cured. Then a special paint is applied over the whole area where the repair was made and where future corrosion could occur. This paint is not affected by engine oil. The engines which have had the pan repair and have already come back at TBO still have the paint intact.

I asked if O.A.E. would clean and apply the paint to a good oil pan to inhibit corrosion. He said they do that but he has never seen one without some corrosion and no matter how little, their repair stops the corrosion and protects the metal all around the area.

The other pan I had was sent out for weld repair to a shop in Anchorage that does weld repairs on Magnesium pans. They have not been able to weld mine without having the repair area show small cracks under dye penetrant inspection. O.A.E. will not work on a pan that has been welded on because of the cracks that are there. I don't know of any other repair that might work, so it looks to me that O.A.E. is the only approved method left out there. We'll see how long their repair lasts. I'm betting it will.

Otherwise, with my other pan, it would probably be fun to cut it up into pieces and throw them into a camp fire. That should be impressive.
Richard

[GAHorn]

Corrosion is promoted by an electrolyte and acids. This should remind everyone how important it is to:
1. Operate your engine regularly to it's normal temperature, and keep it there for a prolonged period. (A minimum of :30 mins flying should do it.) Do NOT use "ground runs" in the mistaken idea you're doing your engine good. All that does is add water and acids to your oil, and wear to your engine.
2. If your engine is to be stored for any length of time, drain the oil and flush the pan, and store it using preservative oil. such as AeroShell Fluid 2F. Do this in accordance with your engine mfr's instructions for long term storage.
3. If you intend to store for shorter periods, keeping it in flyable status, but not fly regularly, try to store it with a fresh oil change in it. Fresh oil will have less corrosives and less water in it. Plug all engine opening including exhausts. (I use a small Dixie cup upside-down in my exhaust tailpipes...a perfect fit. I stick those brightly-colored plastic pot-scrubbers in my vents and inlets to carb and cabin heat systems as an anti-insect device also.)

[170C]

Those we saw at above mentioned facility in Kelowna looked really nice and the coating covers the entire interior of the sump. They charge $400 to do the C-0300 sumps. If you send them one and it can't be repaired they don't charge you for anything but freight.