You most be talking about small engines, I'm talking about all MY engines, small or large, cars,trucks,tractors(small&large). All factory filters are bypass filters. Do you know why they are called bypass filters?
I
am talking about bigger engines like truck and tractors,
I have a host of them, 7 tractors 3 loaders and 5 trucks.(all of them diesels 100 hp or better)
Yes i know about the bypass feature of a lot of filters but not all of them have it, sometimes the by pass is incorporated in the filter base in the block like on my GM 6.5 diesels.
I have 2 older Belarus tractors with just a factory spinner flter on the engine(do you know what a spinner filter is?)and no other cartridge or spin on filter.
The oil in these two engines never gets black no matter if the same oil is left in there for 500 hrs.