Just picked up a complete LY6 with 133k miles from a wrecked 2007 Silverado. Was said to run well and came with all accessories, cpu, etc. I got it on the stand and noticed this crank pulley. Was planning to use this for an LSA build. What is going on with this pulley with no ribs? All other accessories have ribbed pulleys. Only damage to external engine was a cracked oil pan. It turns over just fine. Anyone have any ideas?

 

I’d venture to guess that during the accident, the outer ribbed portion of the pulley got dislodged or broke off. It’s separated from the hub portion your looking at in the pic, by a ring made of rubber or polymer like substance. The rubber like separation ring is what gives the pulley it’s damping characteristics. Since your going with an LSA huffer, you’ll end up changing this out anyway to get the correct spacing for the accessories and blower belt alignment.
My concerns here would revolve around making sure the crank snout isn’t warped or bent from the impact. You could mock up a new balancer in place and then by using a dial indicator setup on the face of the pulley, turn the engine over by hand and watch the dial indicator for runout. Would be much easier to find a bent snout now, vs. finding it after startup. Of course, then again, these engines get pulled at the yards often with front end loaders and very crude techniques utilizing cutting torches and very unmotivated workers. The pulley could have met it’s demise in that manner just as well.

 

stock LY6 2008 pulley for reference