Inner sactum oil galley plug

Jadaharabi said

A couple of the things that can happen with that plug out are:
1 the oil bypasses and goes up to the oil galleys without entering the filter.
2 the oil back feeds through the oil filter and causes the pressure in that area to build up and cause the bypass in the pump to bypass.

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I think your #1 is correct.

The pressure to both passages to and from the filter would be essentially equal so there is no pressure to push oil through the filter. I suspect it will gradually fill up the filter and passages. The non-filled filter would be a huge air pocket in the system so the oil pressure might well fluctuate until/if the air gets purged out of there.