Ford Repair: Oil filter seal, path of least resistance, blowby

Question
Steve,
    I thought the same thing at first, but then I watched the filter closley, using a starter button, and as soon as the rpm's come up a little the filter literally puffs up like its going to explode and you can actually see it move to one side as the oil pushes past. Its like the oil can't get any further and just takes the path of least resistance. I assure you that the mating surfaces are clean. I know that there is a blowby for when the pressure is too great but how do I test that? Thank you for your response. Believe me, I wouldn't have asked you unless all of the obvious answers were ruled out.

         Bill
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Followup To

Question -
I have an '82 5.0 HO that keeps blowing out the oil filter seal and dumping the contents of its crankcase onto the street. The engine runs good other than that, not so much as a noisy lifter. I removed the engine and disassembled it, hoping to find blockage of oil ports and found nothing. I even actuated the oil pump with a drill and all seems normal, the oil goes up to the top and rains down evenly. Is there something I'm missing like blowby? If so please enlighten me. Thank you.     Bill.

Answer -
Bill-

  The first thing I'd look at is the surface where the filter mates with the block.  Sometimes if someone does a crappy job of installing a filter (especially forgetting to lube the new seal), the old seal gets stuck on the block which makes sealing practically impossible with a new filter.  And it's rarely something you'd notice unless you looked at it.  That's pretty much the only reason I can imagine you'd be losing filters like that.  If it were an issue of pressure I would imagine you'd have other problems as well like leaky or blown gaskets.  Hope this helps.

Steve

Answer
Bill-

  Hmmm...that's just plain weird.  There's obviously got to be a pressure build up somewhere.  The question is where.  You might try hooking a pressure gauge up to the oil pressure sending unit.  Sometimes...not often, but sometimes...when the internals of an oil pump wear out instead of dropping the pressure, they increase the pressure.  Like I said, I would've expected a gasket to go first if it was a pressure issue, but maybe the filter really is the path of least resistance.  That's honestly the only other explanation I can think of.  You might try replacing the PCV valve or adding breathers just to make sure crankcase pressure is being vented properly, but if that were the problem I would expect other symptoms.  Hope this helps.

Steve