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

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

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.

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.

Yeah, Loctite 660 doesn't fuck around. They now sponsor Racing for our Heros - they did a demo of that stuff for us. Incredible.

Looks like you fucked up the front cover housing. Better hope that crank seal doesn't leak.

Let's brainstorm, again.

I finally got the car running last weekend. It stuttered a bit as it choked down the last bit of old gas sitting in the lines (I drained the tank, installed a new fuel filter, and re-filled with fresh, ZERO-ETHANOL fuel), but it now idles smoothly and responds normally to throttle inputs.

One problem: use of the power windows, headlights, wipers, etc causes the engine to stumble. This was an issue before I parked the car two years ago, too, only then it would cause the alternator belt to scream as well. I've since installed a new alternator (had it tested before I left the store) and new belts. No more screeching, but it still makes the engine stumble.

Why?

Have you checked your grounds?

Ground, make sure you have a good one.