I won't presume to speak for Thom, or Chris, but I can't help but think that what may be at work hear is the change in bearing surface contact area as the delrin thrust plate breaks in. That is to say, we first start with an extremely small point of contact that as break-in occurs grows to an optimum surface area where further wear is greatly reduced over time. Or, perhaps there is some material in this area of the thrust plate that is meant to give way during break-in.
I forget what it's called, but I remember there was such a material on crank shaft bearings that was meant to safely wear away during normal break-in of stock motors. We used to carefully polish that off when assembling race motors.
I forget what it's called, but I remember there was such a material on crank shaft bearings that was meant to safely wear away during normal break-in of stock motors. We used to carefully polish that off when assembling race motors.