powerstroke, this topic has been discussed thouroughly in past posts. Paper filters, if high quality, do a great job of filtering air when maintained properly. I have worked on and aquired parts for both turbocharged Cummins and Detroit diesel and Mack engines. I can unequivocally can state that on most engines, due to their maintence (or lack there of) that I have come across, would have or are benefitting from the oil-bath filters. Yes, they are messy. Yes, they may restrict air flow more than most dry-type filters. But in the engines I personally seen, whether Cummins, DDA, Mack, or h/d gasoline, valve guide/stem and upper cylinder wear was considerablely less than on engines equipped with dry-type filters. I propose that only frequent and proper maintence of any air filter(dry,oil-bath,oil-wetted) is the only sure and true way to protect any engine upon which they are on. This is only my humble opinion, and am not wanting to start this argument afresh. My dad and grandad who had a GMC dealership in Cullman, Ala. during the production run of this series of engine would not order a truck unless it had both an oil-bath air cleaner and a canister oil filter, even thou dry type filters were a RPO during this time.
