Napa Silver #31085 Cut Open

[KCJeep]

Originally Posted By: sayjac
Otoh, one could accept the OP's incredible conclusion that the nitrile combo valve is designed to 'bypass oil all the time'. But as already noted by Z06 early on, 'if' that was the case, why anyone in their right mind would want to purchase and use such a design is beyond comprehension. That said, I'm 100% certain that if the Wix technical department was to weigh in on the subject, they would dispute that conclusion.


On that point I had another thought also but I don't know how to test it. It is possible the compression the spring generates is enough to push out the combo valve causing a tighter seal in the actual finished product. I have seen that with other rubber parts before. Unfortunatley I knew of no way to test that possibility once I'd cut it. The filter was under far more compression than any other I've opened though.

The gap when disassembled is small, I'd estimate 1/64th of an inch, but if it remains that way during use a little oil is getting past it. I agree I doubt Wix would be quick to admit the combo valve bypass is "cracked" at all times. The fit/finish on the rest of the filter is so good I find it hard to believe the loose combo valve is an accident.

 

[KCJeep]

Originally Posted By: sayjac
What's more interesting to me though, is why some Silver and NPS and other 'made fors' still use the Wix traditional separate metal spring bypass and nitrile adbv, but others use the nitrile combo valve. I'd like to know the major consideration in the differentiation process. Unfortunately, that's likely to stay a mystery.


That is very puzzling to me also. On Silvers I have seen Motorcraft style thread end bypasses (like the Golds except nitrile ADBV), combo valves, and I believe they have some dome end bypasses in the same line as well. All are pretty much the same price too.

 

[ZeeOSix]

Originally Posted By: KCJeep
Originally Posted By: sayjac
Otoh, one could accept the OP's incredible conclusion that the nitrile combo valve is designed to 'bypass oil all the time'. But as already noted by Z06 early on, 'if' that was the case, why anyone in their right mind would want to purchase and use such a design is beyond comprehension. That said, I'm 100% certain that if the Wix technical department was to weigh in on the subject, they would dispute that conclusion.


On that point I had another thought also but I don't know how to test it. It is possible the compression the spring generates is enough to push out the combo valve causing a tighter seal in the actual finished product. I have seen that with other rubber parts before. Unfortunatley I knew of no way to test that possibility once I'd cut it. The filter was under far more compression than any other I've opened though.


Only thing I could suggest is to cut the media cartridge in half so you have the bottom half with the end cap that the combo valve fits into. Fit the combo valve into it's normal resting place and then try to apply some compressive force to simulate the coil spring force that squeezed these parts together. See if the gap goes away between the combo valve and the center tube hole by looking down the center tube. It could be that the compression force makes the gap disappear like you theorized.

 

[96Cherokee]

I just cut open a Carquest equivalent and the ADBV fits tight on the thread size and a little bit loose on the media side. The hole in the metal end cap is slightly larger than the ADBV, check out my post.
Originally Posted By: KCJeep
Originally Posted By: sayjac
Otoh, one could accept the OP's incredible conclusion that the nitrile combo valve is designed to 'bypass oil all the time'. But as already noted by Z06 early on, 'if' that was the case, why anyone in their right mind would want to purchase and use such a design is beyond comprehension. That said, I'm 100% certain that if the Wix technical department was to weigh in on the subject, they would dispute that conclusion.


On that point I had another thought also but I don't know how to test it. It is possible the compression the spring generates is enough to push out the combo valve causing a tighter seal in the actual finished product. I have seen that with other rubber parts before. Unfortunatley I knew of no way to test that possibility once I'd cut it. The filter was under far more compression than any other I've opened though.

The gap when disassembled is small, I'd estimate 1/64th of an inch, but if it remains that way during use a little oil is getting past it. I agree I doubt Wix would be quick to admit the combo valve bypass is "cracked" at all times. The fit/finish on the rest of the filter is so good I find it hard to believe the loose combo valve is an accident.

 

[Toto]

Nice post KC Jeep - Thank You.
I doubt NAPA or WIX would sell and make a less than quality product use it as advertised, New vehicle and equipment warranties remain in effect when Napa Silver filters are used. I think part of the shock is the design is patented and no other manufacturers use it.
TOTO.

 

[ziggy]

VERY well placed, put together, Informative post! kudos!
What is the efficiency of the silver filters? Purolator classics, 97.5%, stp on the box says 96%. What about the silvers? Think thier any good at all, for particles below 10 um?

 

[KCJeep]

Originally Posted By: ziggy
VERY well placed, put together, Informative post! kudos!
What is the efficiency of the silver filters? Purolator classics, 97.5%, stp on the box says 96%. What about the silvers? Think thier any good at all, for particles below 10 um?


Thank you!

If there is a published efficiency rating I'm not aware of it. The Wix/Napa Golds are in the low/mid 90's IIRC, I'd guesstimate the Silvers are most likely below that but I've never seen an independent test on one.