dropped valve damage to E31 head

was this a result of over reving or a weak valve spring ? or a combination of the two ? good picture , worth a 1000 words.

beandip

Thanks for your comments.

there is no sign of overrevving damage to the other valves or pistons so I think it was due to a weak valve spring or possibly a poor repair job somehow ( the engine had a new head gasket on it when I pulled the head)

E31 heads are rare over here. I'm glad the damage appears 'fixable'.