My son has a '02 F150 w/4.6L V8 that suddenly developed a clanging/banging sound from the engine. Long story short, valve for no.4 cylinder was stuck in the guide!!!! Don't know if this is an "interference" engine or not but no other damage was found. Head off to machine shop for guide and valve replacement. Never heard of this happening before. Weird!!

 

Seen it happen on old school engines, was there any visible sign of damaged to the piston. Do not know if these engines will hit or not.

 

these motors ARE interference engines.

 

There was no evidence of piston strike! Must have stuck about half way or so open!! Lucky. 'Mo

 

Dumb idiot engineers, haven't learned from their own mistakes or to stubborn to listen to their elders.