Today's Lesson: Don't fly with a cracked spinner.
The bolt that holds the spinner on didn't break when the spinner self destructed. So it became a big weight and unbalanced the motor. The firewall broke free of the motor box and the prop hit the cowl stopping the motor.
I'll have it repaired before I go to sleep tonight BUT I need a new spinner, prop, muffler and cowl.
So, oddly enough, the motor box failed at an epoxy glue joint. The dowel pins got sheered off. It broke up one side of the box but the other was intact. So the lightened box is not as weak as you might think.
The repair will be done with 100% M100XF Mercury CA. In fact I think I'm pretty done with epoxy. I'm putting the bits back together and then I will plate the sides with 1/8" ply. I had 8oz of weight on the nose so added weight is not a problem.