Anyone know someplace that does case hardening for crankshafts? I had to have my 2.4 crank turned down and i want to have it hardened again. I've read all the arguements on both sides. I'm just looking for someplace that can do it correctly and on time.

 

there are a number of custom crankshaft companies that offer nitriding as a service. Check with them to find out the sequence of turning/grinding compared to the nitriding. it's not cheap...

 

if your crank is factory mitsu, it was not hardened at factory. turning crank down does not loose anything by way of hardness

 

That's true of the second generation cars but i was under the impresion that 1G cars and EVO's have hardened cranks.

It's also a 100mm crank. The guys at AMS told me they didn't like using turned cranks because of the nitride treatment. I've read a lot about it and found a company that does aircraft motors. They charge MUCH less than the cost of a new crank but i would rather send it to a shop that specializes in automotive stuff. I've already had it turned .010 but after that i found out that the shop didn't do hardening and they mostly work on GM stuff. GM says it's ok to go .030 on their cranks. Mitsu says to replace them.

From what i've read there are people who have had failures early in non-hardened turned cranks. There are posts from people who have been running turned cranks but usually they have very few miles on their setups or it's a drag-only car.

 

Lunati is the place i'm going to go for anyone searching this thread. They offer the service with all the trimmings (polish straightening exc) for just under 300 bucks.

 

Just a late update. I got the crank back in about 2 weeks. It's VERY nice. It has been re-hardened. You can tell because the metal is a different color than the factory crank now. The bearing surfaces are mirror polished as well. (I didn't really expect this quality)

The machine shop said it was straight and would be fine to put in as-is. (I wanted to get a second opinion before i dropped it in the car)

I'm waiting for .25mm under size bearings from Summit.

After going through the process i would highly recommend Lunati. It saves a LOT over buying a new crank and should hold up as well if not better than the factory finish.