I best my last thread to death on better fuel filters and now I would like some input on better oil filters for these 123 diesels. Kent at MS likes the polyester filters but they aren't available for the pre 1986 models and we have the pleated paper units which are adequate of course but I have used by pass oil filters from Amsoil, Lubrifiner and motoguard in the past because these conventional full flow filters are in the range of 15 micron and the low flow by pass filters from Amsoil are 2 micron. Getting micron data from other manufacturers like baldwin seems tough and I see numbers in the forums of 18 to 2 microns on their by pass units.. I like the Amsoil by pass units but they are stupidly expensive with just the filterbases alone over $60 and the filters are over$50, There are also other companies like FS which have units that look pretty nice but very pricey. I have tapped the aluminum tops of the 123 filters for the oil supply input in the past and tapped the valve covers for the return but I would like to have filters that not only remove small metallic contaminants but all the carbon soot. I do change the oil from 3000 to 5000 miles at most and maybe this is just neurotic OCD blathering but I just replaced a turbo whose bearingas like clean cool oil so I am fishing for ideas. Independent studies would be the best but I haven't seen them.