Send it in and get a new case for it. Cracks in engines do not get better and JB Weld (in this type of situation) is like a Band-Aid on a broken knee.
If that crack migrates and looses the mounting lug, you may have not only completly ruined the rest of your engine, but may in fact loose your airplane if the engine parts company with it.

Just my two cents worth.

Fuelman