104.980 part identification
 

I am putting back together my 1990 300ce 104.980 that I did not take apart. I have a part that at first glance looks like a wood-ruff key with one end ground off and a notch on the flat side. Its approximate size is 10mm long, 5mm tall and 5mm thick. I had to rescue my car from a mechanic gone bad and ended up with a box of parts and a half assembled engine. It is possible that the part fell into the box at his shop, but I do not think so. I can almost complete assembly and see no place where this part could go.

Definitely a woodruff key that has been damaged.

I would think that the crankshaft balancer/pulley is the only place that it could have come from.

That is the first part that I related it to, but, I have the crankshaft wood-ruff key and it and the pulley are in place and I have turned the crank by hand. The one end could be sheared off, but, the groove/notch looks too straight and deliberate to be the result of some damage. Attached is another angle of view. Thanks for reply.