Do larger oil filters make the bypass valve irrelevant?

[Tyrolkid]

Hey guys-

I've been playing around with larger filters on a number of cars. These filters don't always have the same bypass valve pressure rating as the OEM filters. However, they are significantly larger in size and flow(sometimes up to 3x original filter size). Given the large amount of media and flow, would this not reduce the pressure differential across the media at any given time? Thereby reducing the amount of time the bypass valve is in operation, and potentially rendering the valve inoperative??

-Mike P

 

[Al]

Well, let's face it the larger filter should go to bypass less often. However if the bypass is set lower that would offset the advantages. But filtering willstill be better IMHO. Bigger is better

 

[cryptokid]

quote:

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Do larger oil filters make the bypass valve irrelevant?

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this is what i am hoping by installing an oil filter thats about 4 times bigger than original. its also gives me 33% more oil capacity.

 

[unDummy]

Oil pressure bypass slowly bleeds oil past the filter when the filter is beyond capacity.
Three ways this could happen:
1. Filter is clogged or collapsed
2. Oil flow volume exceeds filter capacity
3. Oil is cold and way to thick to squeeze by the filtering media.

#1 happens when engine is toast.
#2 happens on almost every engine. From what I remember from tech school, almost all engine's oil filter starts bypassing slowly(or exceeds filter flow tearing media) between 3-5k rpm. Bigger is better and allows more filtered oil to make it to the engine.
#3 only happens during very cold starts or if oil viscosity choosen is too thick. Mudoil additives don't help and could cause bypass earlier in rpm and longer as oil warms up.

There are filters without bypass valves. These were used in vehicles that supposedly had filter bypass in the oil passages(think checkball and spring which usually sludged up).

For example:
Nissans older engines(standard filter thread) did not use filters with bypass. These engines tend to develop valvetrain ticking and chain/tensioner issues as the mileage piles on. A simple solution would be to use a larger filter with bypass for silent cold starts and full oil pressure when cold and at higher rpms.

Bypass is never irrelevant.
Check specs of your specific filter(crossreference) at wix/baldwin/purolator/fram filters if bypass is required.

If in doubt, list the filter brand/#/vehicle and if I get a chance, I'll look up the specs.

 

[Mike_dup1]

Does anyone know the reason for the oil pressure bypass valve?

The oil pressure bypass relief valve in an oil filter is not the same as the anti-drain back valve.


Its there to assure proper oil (safety measure) flow at all times under all operating conditions. If something were to plug the oil filter or cause it to collapse the oil would still get to the engine. The oil gets pumped from the oil pump right to the filter, so if the filter is restricting flow, the rest of the engine is starving for oil and could be the end. It amazes me that people want to bypass safety measures designed into these fitlers or engines.

[ February 03, 2003, 12:13 PM: Message edited by: Mike ]