Mattylad says :-
You may not have heard the valves itting depending on what speed you were doing.
My first was at 70mph, trashed the lot.
last one was on a back street very slow, no sign except for the sound of tapping.
Well.............
Think about this......Engine running at 3000 rpm, piston goes up and down 50 times a second..... you got no chance of saving it even on tick over.....Derrrrrr