you dont use wd-40 as a after run oil  its used as a cleaner.  wd-40 will not hurt for a few days  it will take quite a while for the wd-40 to hurt the bearings. if wd 40 hurt bearings right off my engine would have been done long ago.  ive used wd-40 for the past 2 years and no problems.   yea if wd 40 is left on the bearing it will ruin the seals  bot it has to be on there for a while .  as far as the silicon in the crankshaft i have no idea about that  but if you dont have a full race motor  it will not have the silicone in the intake port.