Check valves in oil filters

[Paul Eastham]

I ran a few Champion oil filters in my airplane, and switched to Tempest recently. Now that I've switched, I notice my oil pressure takes a few seconds to come off the peg after starting. The Champion would be rising instantly after start, but the Tempest takes a few seconds.

I also notice I seem to have more oil in the sump, after the first flight post-oil-change (i.e. the Tempest filter doesn't seem to be holding as much oil)

So, I'm wondering if perhaps the Tempests lack the check valve that supposedly keeps the oil in the filter.
I haven't yet removed one of the Tempests from service so I can't say for sure.
It would be nice if it's not full of oil like the Champions...

Anyone else noticed this? Think it's any better for your engine to get that oil pressure up a few seconds faster?

[captainron]

Oil filters, depending on their application, typically have a check valve that will allow oil to bypass the filtering media in the event that the filtering media can no longer flow enough oil through it (clogged). A lot of filters also have what's known as an anti-drainback valve, usually the rubber disc that you can see just below the large oil inlet holes in the mounting plate. Filters that are to be mounted in other than a vertical location (with screw-on mounting plate in the "up" position) should have this anti-drainback valve to retain oil in the filter after engine shut-down. At least on cars, some brands seem to work better than others in this aspect. Why take the chance with your engine? Go back to the brand that was working better for you.

[Paul Eastham]

Interesting, thanks for the information. I do have the 45-degree oil adapter so the potential for the oil to drain out is definitely there.