At the risk of getting flamed

[Zero]

Are there any oil filters out there that are not manufactured with a bypass valve, if so which ones? I was looking into some filters yesterday at Wally World and it appears the Purolator Classic and AC Delco filters do not have a bypass.

Explain to me what happens when the filter is in bypass mode; does the oil just return to the sump or does it lubricate the engine "unfiltered"?

Thanks.

 

[Shannow]

Filter bypass lets unfiltered oil into the oil galleries.

It protects against blocked filters starving engines.

 

[Sayjac]

There are some filters without a bypass, but if so they are spec'd that way by the vehicle manufacturer. AC Delco and other aftermarket equivalent applications could well be one because a large majority of GM vehicles have the bypass built into the engine, so an integral oil filter bypass is unneeded.

And yes as mentioned, when a filter is in bypass unfiltered oil is returned to the engine. But, best information says in pc use these events are relatively rare and of short duration.

 

[RF Overlord]

^^^what they said^^^

Unless you're buying counterfeit knock-offs, if a given filter doesn't have a bypass, then the primary application for which that filter is intended doesn't require one.

 

[bigt61]

Oil Filters: Why Failure Is Not An Option

http://purolatorautofilters.net/news/Pages/OilFiltersWhyFailureIsNotAnOption.aspx

 

[Stelth]

The idea of a bypass is to prevent oil starvation. Unfiltered oil could possibly cause damage to your engine, but no oil flow will definitely cause problems.

If an oil filter has, say, a 12 psi bypass, it doesn't mean that the bypass opens at 12 psi of oil pressure. It means that when there's a difference of 12 psi between the pressure on the inlet side of the filter and the pressure on the outlet side of the pressure, the bypass valve will open enough to equalize it.

 

[HTSS_TR]

Are there any oil filters out there that are not manufactured with a bypass valve ?

Yes, most if not all cartridge oil filters are without bypass valve and no ADBV either

 

[ZeeOSix]

As sayjac said above, many GM V8s have the filter bypass in the engine block near where the filter mounts. Here's an example, the PL14006 which is used on the Z06 and many other GM vehicles. Notice it lists "Relief Valve P.S.I." as "None".

http://www.purolatorautofilters.net/resources/Popup/Pages/PartDetailPopup.aspx?partnum=PL14006

Used on all these 164 vehicles:
http://www.purolatorautofilters.net/reso...4006&page=1

 

[dnewton3]

GM has taken that approach, but so have many other brands. My VG30E Nissan in my wife's Villager also has the bypass in the block and not the filter.

Does not really matter where the bypass is, as long as there is one, and it functions properly as needed. In-block or in-filter; two roads to the same destination.

 

[ZeeOSix]

Originally Posted By: dnewton3
GM has taken that approach, but so have many other brands. My VG30E Nissan in my wife's Villager also has the bypass in the block and not the filter.

Does not really matter where the bypass is, as long as there is one, and it functions properly as needed. In-block or in-filter; two roads to the same destination.


I'll throw a little spin on that. When the filter bypass valve is built into the engine block, it leaves less bypass valve "headroom" for filters that are on the "restrictive" side of flow performance. Even though the restrictiveness of filters probably doesn't vary a whole lot, it's just that if a filter on the restrictive end of the scale is used then that puts the bypass valve that much closer to opening.

Case in point ... SuperBusa asked Purolator if the PureOne PL14006 filter was flow restrictive because he didn't want the bypass valve on his Vette to open up at high RPM. That is why this bench test was done by Purolator. I think they wanted to know themselves because they never really thought of that aspect. They probably don't run bench tests for every guy that emails them asking for flow vs PSID data.

http://www.bobistheoilguy.com/forums/ubb...451#Post1619451