How was the flow rate through this filter when removed at 30-35k? Those sure are well built filters, seems like they could go a long long time in service, maybe 2-3x what you've run yours in a newer common rail "clean" diesel that produces significantly less soot than an old mechanical diesel. Also I'd imagine that since soot takes time to grow from the submicron level to a size at which it can be captured by a 2um bypass filter that if the oil is changed frequently due to other condemnation factors that this bypass would last even longer.
Thanks for the post, would love more details on this, such as how long was the oil run or how many oil changes were run through this bypass prior to changing the oil or bypass, any UOA associated with your bypass system, etc.
Thanks!