I have a 11.1 60 series in a tandem Kenworth dump with an allison automatic. Truck runs drives and handles a load very well. For the most part it does not use any oil. The problem I am having is excessive blowby out the crankcase vent. Since I am not lacking power or using oil is there anything else that could be causing this besides wore out rings? Just seeing if there are any other ideas out there or if we should just inframe it this winter and be done with it. Unknown engine history.