Oil filter question
Been using Fram PH16 oil filters in my XJ and YJ for years probably because they are what the local parts place sells. Anyways, took a couple of old used ones apart recently with a filter cutter for inspection. The spring for the plastic bypass valve seems kind of wimpy...it only takes less than 10 lbs to fully compress it. However, by comparison, the spring taken from a Champion aircraft oil filter doesn't hardly begin to compress with 10 lbs of weight on it. Just wonder how much oil the Fram filter is filtering and how much it may be bypassing. Anyone have any input on this? Thanks.