What's the name of the TYPE OF SPRING in the 5th picture down?
I know it's the bypass mechanism.
NOTE: I always wondered how precisely the bypass pressures are maintained.
Everybody wants a $3 filter so how precise can they be?
Denso Toyota oil filters from Japan used the exact same type of bypass spring. These came on new Toyotas made in Japan in earlier years. Some one else said the name. I don't know a different name, flex plate spring?
Fram will give a bypass range, from start of open to max open I would guess. It's probably pretty accurate like a pound. Others just give one number, don't know what that refers to except maybe the middle of the range, or it could be the start. Fram is better than most with their tech specs. I don't think when Fram says 19-25 bypass it means their spring is so unpredictable it could start to open anywhere in the range. It should be the start to max.