1990 mazda b2200

haven't posted in awhile soooo..... motor is torn apart and someone decided to put a cam seal in and the woodruff key messed up the hole it sits in and messed the crank and harmonic balancer sooo the block, head and pistons are at the machine shop as we speak. Im really stoked about this build hope all is well

This is a somewhat common problem, not due to design, but due to a typo in the Haynes manual (I think), one of the common repair manuals says to tighten the front crank bolt (the big one) to 14 ft/lbs, it should be 140 ft/lbs (going by memory, could be 17 and 170, basically the missed the 0 at the end). This leads to the bolt loosening, and wobbling around, causing the keyway damage, and the tip of the crank to wear. My truck had this issue when I got it, and I never could get the front crank pulley to stop wobbling, it will get worse to the point of breaking off the tip of the crankshaft. Since you are getting it rebuild, you should replace the crankshaft, new keyway, and a replacement front pulley, that is what I did.