Removing corrosion from crankshaft prop flange....

[jtrom]

What's the best way to remove the corrosion from my O-320 prop flange? I will be removing the crank for overhaul. Can this area be grit blasted with crushed walnut shells or other media? Any suggestions?

[Blue Chips]

That is how I would clean it, walnut shell, soda blast or very fine glass blast at low pressures, none of which will remove any metal just clean.
Likely that was Cadmium plated at the first and will require something to inhibit corrosion.

Ken

[WLIU]

If you have some time on your hands, start with scotch brite. That and some elbow grease will take care of 90% of the corrosion. Then inspect with a 10X magnifier.

The Lyco crank flange is not plated. Wipe it down with an oily rag. I scotch brite and inspect my crankshaft flange every 25 hrs to comply with an AD about aerobatic airplanes. No sign that it is or was plated. But mine stays pretty shiny.

Best of luck,

Wes

[Bill Berson]

I use liquid Ospho ( phosphoric acid) to etch the rust away. Brush it on, let soak then scrub with a wire brush. Might take several applications if pitted.

[cub builder]

I think you'll find that if you send this to a crankshaft shop for overhaul, they would bead blast the corroded area, turn the flange down to remove the pitting, then cad plate it to prevent further corrosion. That is the correct repair procedure for it. Fortunately, the corrosion doesn't appear to be very deep, so there should be plenty of meat on the flange for it to still pass. Crank overhaul shouldn't run over $600 if the crank is still good, even including regrinding and nitriding if needed. However, the caveat is that many perfectly good Lycoming cranks are being rejected at the overhaul shops upon inspection for compliance with FAA A.D. 98-02-08.

CubBuilder