My crank pulley was wobbling and my timing kept drifting on me, and I finally figured out why -- the key in the crank sprocket sheared off, doing a little bit of damage to the crank nose. I actually figured this out when turning the crank by the sprocket bolt with a wrench -- it started to loosen just by rotating the engine by hand! It's my guess that the previous owner of this engine never torqued it right. I'm not 100% sure if my head/valves escaped this unscathed, but I do know that at some point the timing was at *least* 5 teeth (relative to the camshaft) off! I corrected the timing today before discovering this issue and the car ran fine until the timing drifted out of whack and the engine died again.
Now, obviously I need a new crank bolt and sprocket, not too hard to get I don't think. The only thing I'm worried about now is if the wear on the crank keyway is going to cause failure again. As you can see in the pics, it definitely did chew up the lefthand side of the groove. I'm reluctant to use pins, since the other option at this point is to find a good shape 9A block and transfer my PL head onto it for (as I understand it) quite a nice performance boost - but quite a lot more time & effort.
Opinions? Is my crank done? or should I just pin it?