> The > > biggest problem is it only filters half the oil. > > Warren, doesn't all the oil eventually circulate throughout > the engine, or > does it tend to circulate in certain parts of the case? > I think what's being referred to here is a "bypass filter". Continental had a bypass filter available for the C-series engines years ago. If memory serves, it was made by Fram. A bypass filter takes high pressure oil just after the pump and sends it through a very fine filter which drops the entire oil pressure. The oil flows back into the sump, not back through the engine. This allows the use of a much finer filter. Todays's filters are primarily "full flow" which means all the oil goes through the filter on its way to the vital parts. These filters must necessarily have a much lower pressure drop and consequently do not have the ability to filter out as fine a particle. Big diesel engines still use bypass filtration, often along with full flow filters, to extend oil change intervals.
Oil coolers have a built in thermostatic bypass so that they can control the oil temp. Otherwise, on a cold day the oil would congeal in the cooler and block up the system. BTW, airwolf filters makes an STC'd remote full flow filter for the C-series as well as just about everything else that flies with mags. Just remember, if you've got a filter, then you ought to be cutting it open every time for inspection... John
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