What caused this?

[kwhizz]

I have been as high as 8,400 rpm, 8,000 plenty of times, and shift it at 7,200-7,400 so a stock balancer is NOT happy with my methods LOL I have broken 2 ATI balancers on my Buick like yours, and that was because they were too loose on the crank snout. "QUOTE" Buizilla

The ATI balancers are made from "Junk" material that is easy to machine but does'nt hold up to any abuse at all...On ProCharger blown engines the ATI balancers can't take the belt tension and the hub elongates and loosens on the crankshaft..........The material they use is probably leaded stock (Easy to Machine) and has little yield and or Tensile strength........Whenever we run into this problem we make new inner hubs for the ATI balancers out of 4150 Pre-Hard material (28-32-Rc) and the problem never returns....Talked to the ATI Tech guys and they didn't know or care what their Hubs were made from or that they were failing under a little abuse........Imagine that

Ken