Cranks can be resurfaced, polished, and ground.
I only go as far as resurfacing/polishing where the bearings ride.
When people grind the cranks down, so they can run a larger bearing, this is when you see problems and failures. The ONLY reason to grind a crank is if you had one spin and the crank surface is damaged beyond repair and you have to remove material and "start over" so to say.
Not all shops can do this correctly, especially on one of our "mild steel" cranks. Takes the right tools, and knowhow to pull it off, and even then...you can do everything right, but the quality of the crank will bite you in the ass sometimes.
I feel, in my opinion, if you have to grind on a crank for what ever reason on our cars, scrap it/**** can it, and get you a new/lower mileage crank to use and run that.
~F~
