So I found this today, after ruling out spark and fuel on a dead cylinder.
What might cause such a catastrophic failure like this, so I can avoid it going forward?
It's been getting below freezing at night here, though I always let the car idle for 5-8 minutes until the water temp gauge starts moving, and never drive it hard until the
oil temp is fully up.
I did have it in the shop over the Summer for some work which involved taking the valve train apart. Possibly damaged then or mis-installed? Seems like that would have happened much sooner if that were the case.
Hopefully, the valve is not bent.. or worse!