There would be no way for the keeper to make its way into the oiling system unless there was no screen on the oil pickup tube. Also the oil filter does not filter all the time, if the pressure differential is to high it bypasses the filter, normally with cold oil or high RPM, which results in high oil pressure. MustGoFaster can chime in on this if he wants.
All you need is a rag to avoid any possible issues. Also here is a filter that does not bypass at all:
http://www.buickgn.com/oilfilters.htm
~John
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