I think I need a crankshaft

[jibby212]

I was preparing to mount my O360 that has been inactive for a few years but with 3HSMO when I noticed the valve springs heavily rusted. I tore the engine down and I think the cylinders will be ok, I ordered a hone and a set of rings, The oil relief spring was in two pieces, the cam was actually the only thing that had no corrosion. The crank has some pitting that I figured would be fine , none on any of the bearing surfaces except the #2 main bearing fillet. I just read in the Lycoming overhaul manual under corrosion that this is unacceptable. This is pretty depressing, for the first time in the build I am pretty much at a standstill. Is this a doomed crank?, Anyone have a good one for sale at a reasonable price?

[rocketbob]

You have to measure to see what you've got to work with.

[Jpm757]

While you're at it, if it's a hollow crank, check the inside for corrosion per Lycoming SB 505B.

[James Ball]

A competent crankshaft repair station can inspect and, possibly, polish your crank and tag it airworthy or grind it undersize and re-nitride harden the journals. Bearings are available in M003, M006, and M010 sizes for the undersize crank. If you have as standard crank, with time and effort, some crankshafts can be polished to M003 and not need to be re-nitride hardened. Talk to the shops that do that kind of work, Rick Romans, Aircraft Specialties, and others. If you have to buy a new crank, the best deal is the Continental Prime brand through Aviall or one of their sub-tier distributors.

[lr172]

I suspect that dealing with corrossion in the fillets is harder to deal with. It is likely that they can deal with light corrossion there. However, I would still spend the money in shipping to have it evaluated. Most will inspect at no charge or for $100. Seems like a wise investment before dropping $5K on a new crank.

Can you tell how deep the fillet corrossion is?

Larry