The narrower stock piece places the load on the base of the stud, where it goes into the timing cover.
The 318i adjuster arm has a wide boss and can possibly spread the load to the front of the stud by having a wider load surface.
I've got my fingers crossed that this will work!
I just noticed again that my car has a strange electrical gremlin that first reared its head before the timing cover stud broke.
When the engine is running, my foot is on the brake pedal, and then I turn the key to the off position, the engine still runs. I can even remove the key. Once I take my foot off the brake, the engine finally cuts out. If I put my foot on the brake, with the key in the off position or removed, the red alt. light turns on along with the gas gauge.
I can't understand what would cause this??