? on oil filters and preasurized releif valves

[qwik219d9]

why do some oil filters have preasure release valves and others do not?

If I remeber corectly some imports require a preasureized relief valve becauce of where the oil fiter is mounted like high on the engine.

I'm thinking the spring actuated valve is like a priming at intial start up.

I'm wanting to replace a prema cool extrenal filter, using as a extra trans. filter and it has the valve.

prema cool has not responded to serval emails and answering machince messages I say don't buy there products.

http://www.summitracing.com/parts/PRM-10675/ I'm not interested in paying summit $15. for filter and $10. to ship. would prefer to buy locally.

hopefully someone here knows about oil filters.

Thanks

[Cutlass]

By-pass valves help keep the engine from becoming oil-starved during cold weather starts or if total filter blockage exists

[Cutlass]

I came across a cross reference online that says:

Brand-- Long(5.25")/ Short(3.5)
AC-- PF2/ PF13
FRAM-- PH8A/ PH43
LEE-- LF1/ LF16
MOTORCRAFT-- FL1A/ FL173A
NAPA-- 1515/ 1068
PUROLATOR-- PER1A/ PER17
PERMA-COOL-- 81008/ 81043

[qwik219d9]

By-pass valves help keep the engine from becoming oil-starved during cold weather starts or if total filter blockage exists

if total filter blockage are you saying if the filter gets real dirty the valve closes not allowing the dirt to flow back into motor?

My observations on the frame expensive high mileage filter (has the valve) compared to the regular frame no valve.

thinking it's better to have the valve?

Thanks for the infor. I'm planning on replaceing the prema cool w/ a Wix BTW it has the valve. also I'm planniing on not dropping pan to replace the filter inside trans.

[Cutlass]

No if the filter plugs, the oil bypass's the filter and goes directly to the bearing without being filtered.