I have make an inspection after 6 hour since i have start my refresh engine and my new b&m 250 blower have one seal poped out there place and touch the the rotor end. It is probably due to an over air presure in the rear bearing plate. I want to know if it is a common problem with that blower and if I can do a mod like drill a small hole to get the air presure out of the bearing rear plate? Or run with less grease and instaling the seal with red loctite?

Has anyone ever had this experience with this blower?

I would give an expert a call. I have my B&M 250s serviced by Supercharger USA. Call Tim there and ask him what he thinks. His number is 714-209-7531. You could call The Blower Shop as well.