Do you pre-oil your filter medium (not just the ring). I'm talking about dumping some new oil in the new filter prior installation to get the filtering material saturated with oil and limit starvation during initial start.
All of mine are vertical and I pre fill them ... does it add value? - dunno - but it's just one of the little things you might feel better about when DIY ...
Yes, always. It can only help and I don't see any downside to doing it. On filters that are horizontally mounted, I fill the filter about halfway and I can get the filter on without spilling a drop. Even on my wife's Subaru, where the filter mounts on top of the engine with the threads of the filter on the bottom, I can quickly turn the filter upside down and get the threads started before any spills out.
Ive had MORE problems pre filling. I see no issue in maybe filling it 1/2 way - full may cause more problems. I like the wifes FB25 with the top mounted filter - I can prime the system by dumping oil down to the pump and out to the mains. Ironic as the filter is empty and dry every start.
I don't think having an impediment (blob of oil in the filter) 1/2 way up the oiling drill helps. The oil slug from the filter is going to get shot out by the compressed air behind it. Vertical filters below the sump line right at the pump ( ala classic chev v8) could probabaly be filled to the brim without issue.
Maybe a hiccup will unstick a sticky HYD plunger somewhere.
I have always do pre-fill my filters on cars that the filter mounts vertically. On other cars where it is more horizontal, I'll "pre-wet" them with enough fresh oil that nothing comes out if I'm quick enough to spin it and not let it out.
Just makes me "feel" better to do so.
Since I used Purolator (PureONE) for so many years, I'm hoping that doing so might (no evidence here, only wishful thinking) have prevented me from getting any tears in the filter media that some have seen. To my knowledge (cause I haven't cut open each and every used filter in the past), I've never had tears.
But I'm moving on to FRAM Ultras anyways.
I always pre-fill my oil filter whenever possible. I notice that when I don't, there's a little extra noise coming from the engine for the first couple seconds after start up. I figure the pre-fill helps reduce potential wear.
I say "whenever possible" because some filters have an odd combo valve that essentially seals the center hole.