[Milsurplus] Don't pack the bearings

[CL in NC]

Does anybody know the reason it states on dynamotor instructions to not pack the bearings like you would a wheel bearing on a car axle?  Was it the type of lubricant that was available back in the era?  While I don't pack them like a car bearing in the palm of my hand, I do put enough modern synthetic lubricant from Lucas, in and around the ball bearings and the race it could almost be considered packed.  Have not had an issue with them heating up and oozing out the covers.

Charlie, W4MEC in NC