the scoring in the case was caused from the rod rubbing it when the bearing failed.
is the saw stock or ported?
side loading could be the cause, but rare in stock saws. if there is a lot of wear on one side of the of the piston or the pin bosses inside the piston, it's likely the cause.
The saw looks bone stock, all oem marked parts. No port work on the cylinder.
is it a oem or aftermarket crank?
I strongly recommend an oem crank
The trashed crank is Stihl. The one I just bought is Stihl.