Let's brainstorm.

[G-Rex]

Well, I wish you luck.

I'm not one to trust liquid metal, JB Weld, etc. on things like cranks. I'd be dropping the oil pan to swap in another crank, but that's just me.

Hopefully everything works good when you get it all put back together. Otherwise, you'll be going through most of this work again.

[pauldun170]

Originally Posted by G-Rex

Well, I wish you luck.

I'm not one to trust liquid metal, JB Weld, etc. on things like cranks. I'd be dropping the oil pan to swap in another crank, but that's just me.

Hopefully everything works good when you get it all put back together. Otherwise, you'll be going through most of this work again.

that

[derf]

If you are intent on saving the crank you could try to weld it and have the keyway machined out again, but even that would probably either deform the crank, weaken it or both, and you would have to remove it from the block or destroy the seals. Either way you really need to repair it correctly. The liquid metal or JB weld will last a few miles, but either way it will start to wear pretty fast pretty soon

[Triple]

Originally Posted by G-Rex

I'm not one to trust liquid metal, JB Weld, etc. on things like cranks. I'd be dropping the oil pan to swap in another crank, but that's just me.

This stuff isn't like cheap Walmart JB Weld. It's expensive, hard to find, and many Miata owners have used it with much success. I don't understand why it won't harden, however.

You aren't really relying on the liquid metal; for the most part, it's just there to keep things in place during reassembly. They key is keeping the whole assembly properly torqued down. Neglecting that allows the crank bolt to back out and the cog/pulley to shift on the crank nose.

Originally Posted by G-Rex

Hopefully everything works good when you get it all put back together. Otherwise, you'll be going through most of this work again.

The hell I will. If this doesn't work, I'll either sell it as a non-running roller or replace the engine with a warrantied, remanufactured unit. Dropping/replacing the crank can cost as much as replacing the entire long block.