Could anyone tell me the direction and (ball park) rate of flow through an automotive oil filter? Thank you.

Many, if not most, filters have "anti drain back" features that prevent the filter from draining out on shut down.  This little feature makes reverse flow impossible.

   [Pat, guess how I figgured that one out.]

Flow rates are determined by filter size and filter medium.  Larger filter...higher flow (generally)...smaller filtration (partical size) lower flow.  Racing filters tend toward full flow, high flow/low filtration (e.g., Fram HP-1 or Wix 51515R)  whereas "street" filters usually compromise with a small particle filtration capability (as low as 5 microns in some cases) and a "safty valve bypass" valve in the event flow becomes unduly restricted. This "semi full flow"(my term) is usually ok as long as it is changed often and is NOT used in a high performance application. Street equivelents of the above examples would be Fram PH-8 and Wix 51515.  Big difference in filter flow and capacity.  Like anything else, use of the proper filter in each application is paramount.

MORE NEWS