If you don’t have that BMW special tool handy to lock the engine at the flywheel spine, there is a second way to lock the engine as mentioned by
DreiD in this post
http://www.e90post.com/forums/showpo...&postcount=136 and below picture from
Yozh.
As shown in the video and pictures, I used a bore scope to line up the holes and then pushed in a 6mm Allen wrench to lock the engine. Do not forget to remove the lock before attempting to start the engine!