I'm not totally sold on the design of the Thailand-made Roki Mazda filter, 1WPE-14-302.
The thing that bothers me is the possibility of leaks between the outside chamber and the inner core.
The shiny areas on the top and bottom of the media where the filter element interfaces with the steel structure are quite hard, like cured urethane. If those hard surfaces don't conform perfectly with the shapes of the metal pieces they contact, some unfiltered oil will seep across, due to the pressure difference between the outer and inner chambers of the filter.
If you look closely at the photograph of the inside of the top plate, you'll notice the circumferential thin dark line that traces the interface between the filter and the top plate is incomplete. That suggests a gap between the filter and the plate in the area where the line is missing.
At the other end of the filter the hard urethane-like area on the media presses against a stamped steel structure that holds the bypass valve. For the filter I cut open, the marks on this stamped steel piece show evidence of good, continuous contact with the element, at least in the area that is visible in the photo.
Perhaps those hard, shiny areas on the ends of the filter media are somewhat pliable when the filters are assembled, allowing the interfaces to fully seal. I hope that's the case.
The thing that bothers me is the possibility of leaks between the outside chamber and the inner core.
The shiny areas on the top and bottom of the media where the filter element interfaces with the steel structure are quite hard, like cured urethane. If those hard surfaces don't conform perfectly with the shapes of the metal pieces they contact, some unfiltered oil will seep across, due to the pressure difference between the outer and inner chambers of the filter.
If you look closely at the photograph of the inside of the top plate, you'll notice the circumferential thin dark line that traces the interface between the filter and the top plate is incomplete. That suggests a gap between the filter and the plate in the area where the line is missing.
At the other end of the filter the hard urethane-like area on the media presses against a stamped steel structure that holds the bypass valve. For the filter I cut open, the marks on this stamped steel piece show evidence of good, continuous contact with the element, at least in the area that is visible in the photo.
Perhaps those hard, shiny areas on the ends of the filter media are somewhat pliable when the filters are assembled, allowing the interfaces to fully seal. I hope that's the case.