Best way to clean light rust off of steel gears?

[jtrom]

My experimental project has an O-320 that has been sitting for many years. My magneto drive gears (steel ones) have some light rust on them and I assume the other accessory gears probably have some surface rust also. My Lycoming overhaul manual isn't really clear on removing rust off gears, it does say to NOT media blast any "machined surface" (don't know if a gear is considered a machined surface). Is my best bet just to use scotchbrite? Any experienced advice out there on the subject?

[WLIU]

The important surfaces to avoid media blast are the parting surfaces of the case halves. Other parts get media blast. For example, the outside of cylinders get blasted clean.

Walnut media should be OK for blasting the gears clean. That said, I believe that you should plan to magnaflux inspect them for defects as part of the overhaul.

What does your crank look like?

A friend had an engine that had some corrosion on the valve springs. Caused a crack, which resulted in the spring completely failing in flight. The push rod started moving up and down unconstrained, which led to the lifter body breaking up, which lead to all kinds of bad things in the engine. All of the expensive parts including the crank were junk. Was able to re-use the accessory case. Very expensive and all because a spring failed due to corrosion.

Fortunately my friend was within gliding distance of the little airport I live on. Landed OK.

Look that engine over very very carefully.

Wes
N78PS

[Max Torque]

When I was doing overhaul on helo components the norm for that would be red Scotchbrite and/or 600 grit wet dry, Popsicle sticks, light oil and lots of elbow grease.

[martymayes]

it does say to NOT media blast any "machined surface" (don't know if a gear is considered a machined surface).

The teeth are machined surfaces.

[Max Torque]

Yes, the teeth are machined surfaces as are normally the parts of the gear that make up the shaft or ride on the shaft or have a bearing installed in it, etc. Usually, the sides of the gear are not considered such and may be carefully bead blasted.

[Mike]

OSPHO @ sherwin-williams paint store, maybe on ebay.

[jjhoneck]

OSPHO @ sherwin-williams paint store, maybe on ebay.

Agreed. Our island hardware store sells the stuff by the gallon. Ospho is a way of life for boaters and property owners here.

[Kurt Flunkn]

For removing light corrosion from steel, try soaking the part overnight in white vinegar. Then towel drying the part to remove as much of the corrosion as possible, lightly rubbing with a scotch-brite pad, towel cleaning again, and applying a light coat of 3 in 1 oil. I have not used this method on engine parts.

[martymayes]

Soaking the part overnight in Evapo-rust will work.

[Aaron Novak]

Soaking the part overnight in Evapo-rust will work.

Gotta be careful with chemical cleaning. Keep Hydrogen Embrittlement in mind when picking acid type removers.

[martymayes]

Gotta be careful with chemical cleaning. Keep Hydrogen Embrittlement in mind when picking acid type removers.

Gotta be careful with admonishments as well.

FWIW, Evapo-rust is not an "acid type remover" and there is no hydrogen embrittlement in the process. Had it not been appropriate for this application, I would not have suggested it.

[I_FLY_LOW]

electrolysis rust removal is another option.

[Aaron Novak]

Gotta be careful with admonishments as well.

FWIW, Evapo-rust is not an "acid type remover" and there is no hydrogen embrittlement in the process. Had it not been appropriate for this application, I would not have suggested it.

Marty,
Wasn't specificly noting products like you mention. Just a general note when people start talking chemical cleaning that they need to watch what they use.