Back in the mid '70'* I was at Keokuk Dragway in Keokuk Ia. when a car blew a flywheel and a chunk of the flywheel too out a guys radiator who was parked 2 or 3 cars away in the pits( we were all pointing towards the track in the pits).I know of guy who was tunning his race car when the flywheel blew and he had a scar along side his face.
I remember when Jesse James had that series Jesse James is a Dead Man, on one episode he drove a guys Nitro Bike and blew a piston. They wear a cheast plate just incase but have been known to die a couple of days later from internal injuries.Jesse had a friend who died that way. Didn't think anything serious was wrong.He found out that you crack the throttle wide open and don't let up and crack it again or it going to BLOW.