That's pretty wild! Never seen one blow out the top of the valve cover. I would guess the chain is very, very loose, How else could a piece of the rail become lodged betwen it and the cam gear which is what it looks like to me. If you are lucky you will get by pulling her all apart, new chain, guides tensioner and possibly a few gears, several new valves and of course, a new valvecover.

That's best case, I remind you. I bought a 450SL once that suffered a similar fate and the engine was ruined, water in the oil, chunks of metal in the cylinders, etc., I suspect it happened at highway speed.

Free, eh??

__________________
Chas

Had a 380SL, 450SL, 380SEL, 420SEL, 500SEL

Got a Euro 500SEC right now.