here's two for ya - friends tired motor in his Formula Ford just died one day and the motor would turn but not fire. Pull the head off - hey why is that piston not going up and down when you spin the motor. The crank journal came "undone" from the crank - very bizzare but makes a cool paper weight.
The Yamaha 1000 motor in my old sports racer came apart so violently once that I found a piece of Tortalenni Pasta shaped connecting rod wedged in the tranny upper case half , this was't so suprising as chunks of piston were scattered down a 100yd section of track.

"mass X velocity"

Tom Grossmann