WIX Filter Failure

[yonyon]

Originally Posted By: Garak
Originally Posted By: mechanicx
The debate is whether or not working bypasses are restrictive.


That's a very good question. I'm certainly not as up on the fluid dynamics of filters as some of the posters here are. In bypass mode, though, obviously a filter could allow a much greater flow (duh, or they wouldn't have a bypass in the first place - wouldn't be much use if it couldn't accomplish that). How much is the question. More precisely, can it handle the flow if an oil pump's relief fails?


Fram and Affinia both say that it can't. I think it should be safe to assume Affinia has done some testing with Wix filters.

 

[mechanicx]

Originally Posted By: ZeeOSix
Originally Posted By: mechanicx
Filter cans are made to withstand up to 300 psi, and the purpose of a bypass is to allow full flow to the engine during filter element restriction and also protect the element from psiD, ...


Not at 300 PSI and the insanely high flow rate that comes with that 300 PSI.

Originally Posted By: mechanicx
... so it would stand to reason that bypasses are designed to not be restrictive. I don't claim to be well versed in fluid dynamics, but unless a filter engineer states that bypasses are restrictive then I'm not going to just assume that they are.



Again ... it's about the much increased flow rate to the filter that comes along with the 300 PSI from the oil pump - and bypass valves are going to have a tough time coping with large abnormal flows, especially cold, thick oil (broken record going on now

). You don't seem to understand the physics going on when a PD oil pump output goes nuts because the pressure relief valve failed.



And you keep ignoring the concept that if the bypass has the same cross section as the oil gallery feed from the oil pump then the bypass is not necessarily more restrictive to flow regardless if the oil pressure regulator is inoperative. If you believe bypasses are sized too small then fine, but there's no need to keep repeating it and acting all condescending as if you have superior filter fluid dynamics knowledge and expertise. What's next, are you going to say fully opening oil pump relief valves can't flow enough sometimes either?

Originally Posted By: yonyon
Fram and Affinia both say that it can't. I think it should be safe to assume Affinia has done some testing with Wix filters.


Do you have a link where they address bypasses? If they clearly state that, I'll accept it.

 

[mechanicx]

Look at the filter inlet holes vs they bypass holes. Although slightly smaller the bypass holes are more numerous and appear to be equal in area to the inlet. So whatever oil regardless of pressure and volume) that flows in the inlet holes should be able to flow through the bypass unrestricted. So there would not be significant filter element psid.

 

[ZeeOSix]

Originally Posted By: mechanicx

And you keep ignoring the concept that if the bypass has the same cross section as the oil gallery feed from the oil pump then the bypass is not necessarily more restrictive to flow regardless if the oil pressure regulator is inoperative.


And you keep ignoring the fact that when an oil pump does bonkers, it is causing way more oil flow volume to be forced through the filter. Oil filter media and the bypass valve are not meant to take the flow and resulting PSID from a run-away PD oil pump. Even with the bypass wide open, the flow (especially with cold oil) will most likely still be too much for it, and there will still be a large enough PSID across the media to implode the center tube. And when the center tube implodes far enough it's not unimaginable that the top end cap would compress downward too ... just like what was seen in the video.

I'd like to prove it to you by disabling a PD pump pressure relief valve and show just how fast it will destroy an oil filter. That's the only way I could ever prove it to you, and then you'd say it was a rigged experiment and just a conceived hoax or something.

Originally Posted By: mechanicx
If you believe bypasses are sized too small then fine, but there's no need to keep repeating it and acting all condescending as if you have superior filter fluid dynamics knowledge and expertise. What's next, are you going to say fully opening oil pump relief valves can't flow enough sometimes either?


Yes, I am going to say it (and I already said it once), that some oil pump's pressure relief valves can't regulate the pressure very well because of the very fact that they can't flow the shunted oil volume completely. Why do you think people port oil pumps and rework the relief passage?

Like I said, you need to study up on PD oil pumps so you can get out of you rut of thought.

Originally Posted By: yonyon
Originally Posted By: Garak
More precisely, can it handle the flow if an oil pump's relief fails?


Fram and Affinia both say that it can't. I think it should be safe to assume Affinia has done some testing with Wix filters.


No big surprise there.

 

[mechanicx]

You just keep bebopping and scatting around the point that you can't have pressure differential across two passageways of the same area regardless of psi and flow volume.

 

[ZeeOSix]

Originally Posted By: mechanicx
You just keep bebopping and scatting around the point that you can't have pressure differential across two passageways of the same area regardless of psi and flow volume.


You need to realize that if the flow is high enough due to a failed oil pump pressure regulator, and the oil is cold/thick, that there is going to be a PSID large enough to implode the element no matter how far open the filter's bypass valve is open. It just can't handle those conditions and save the filter.

The concept you're missing is that the increased oil flow volume is what causes the large PSID. If the increased volume/viscosity combo is so great that the bypass valve can't keep the PSID down, then the element will be imploded.

I can see there is no way of explaining this concept to change your mind ... that's OK, so be it. Maybe one day it will make sense to you.

 

[mechanicx]

If two passageways (the filter feed and the filter bypass) have the same area they will flow the same volume of oil at the same pressure. Doesn't matter how viscous the oil or how how high the pressure or volume. Both passageways are seeing the same pressure and flow and would by definition of having equal area have equal pressure.

You presist in creating subterfuges instead of addressing how it's possible two passageways of equal area would not be at equal pressure.

 

[yonyon]

mechanicx, how exactly are you going to flow a tremendous volume of fluid through a small orifice without generating a pressure differential? If there is a pressure differential would that not also increase with flow volume and viscosity? If the fluid then travels down a nice fat pipe to another orifice of the same size won't it generate the same pressure differential at that orifice as well?

 

[Garak]

Originally Posted By: mechanicx
So there would not be significant filter element psid.


Very useful pictures. What I'm thinking, and I could be certainly off base with this - others please correct me if I'm wrong - is the following. I'm thinking that the oil pump relief fails and is sending a large volume of high pressure oil into the filter. Of course, it's too much to go through the filter media at full flow, and the bypass is tripped and functions correctly.

However, the oil flow and pressure are still way too much. While a filter in bypass can allow much more oil through, there are limits. It cannot pass an infinite amount of oil nor pass infinite pressure. The pressure and flow get too high, and we have things getting distorted, or even the can blowing out.

What I'm saying is that the bypass in the filter is designed with a couple scenarios in mind. If the filter is clogged, bypass can save the day. If it's a very cold morning and the oil is thick, the bypass will again save the day.

However, these scenarios are based upon the filter and its bypass being subjected to what we would consider normal oil pressure fluctuations, based upon what the filter manufacturer would expect with very cold, thick oil or clogged media.

They wouldn't be based upon the expectation that a pump's relief has failed and is pumping way too much oil at way too high a pressure. The can and the internal structure itself obviously has limitations upon the force they can withstand before failure. For one, a bypass valve in the filter allows for oil to flow without forcing it through the media. However, the bypass doesn't completely isolate the media from the flow - it's not a valve diverting the flow to a completely new fluid circuit thereby protecting the internals of the filter and the can itself.

Basically, the filter can only withstand so much pressure before failure, bypass incident or not. Unless the bypass actually bypasses the filter assembly completely, we are limited but the structural limitations of the filter itself, right?

 

[Hounds]

Garak, your analysis makes sense to me, fwtw. I'm still amazed, however, that the center core could be crushed as depicted here. I'd love to know what the psi number was that caused this. That's certainly a lot of oil pressure! And, in this regard, I'm also impressed that the canister didn't rupture under these conditions. Wix almost certainly knows what would cause that to occur, and that number must be well into the hundreds of pounds per square inch.

 

[SEMI_287]

Who [censored] cares?

 

[Hounds]

Originally Posted By: SEMI_287
Who [censored] cares?


Not you, apparently. Other than your command of profanity, have anything meaningful to add?

 

[mechanicx]

Originally Posted By: yonyon
mechanicx, how exactly are you going to flow a tremendous volume of fluid through a small orifice without generating a pressure differential? If there is a pressure differential would that not also increase with flow volume and viscosity? If the fluid then travels down a nice fat pipe to another orifice of the same size won't it generate the same pressure differential at that orifice as well?


My whole premise is that a bypass is not necessarily a small orifice in relation to oil filter feed channel. Your second sentence illustrates my point that two orifices of the same area will operate at the same pressure differential although I'm not sure if that was what you intended to say.

All anyway has to say is that bypasses can be size too small and be restrictive, and I accept that. But it isn't necessarily the case that a bypass is small and restrictive.

 

[ZeeOSix]

Originally Posted By: Hounds
Garak, your analysis makes sense to me, fwtw. I'm still amazed, however, that the center core could be crushed as depicted here. I'd love to know what the psi number was that caused this. That's certainly a lot of oil pressure! And, in this regard, I'm also impressed that the canister didn't rupture under these conditions. Wix almost certainly knows what would cause that to occur, and that number must be well into the hundreds of pounds per square inch.


Agree that Garak has a handle on it (as well as sayjac a some others) based on his last post IMO.

When a PD oil pump has no pressure regulation, it will force every ounce it can pump down the filter - that's why the pressure goes sky high, because that's the pressure required to force feed the oil of that viscosity down that path. Even if the oil is cold and thick, the PD pump will try to force every ounce it can pump with every revolution down the filter. A failed pressure regulator valve will not allow any oil to shunt back to the sump, so it all goes to the filter - no matter how much pressure it takes.

That's probably what happened in that WIX failure, as the guy said it was cold the night before and the filter puked from the base gasket that morning upon starting. When the oil is cold and thick, a failed pressure regulator will really exaggerate the PSID across the filter.

The center core and media is the weakest link in the filter's construction. If the center tube is metal, it will collapse first with enough PSID. In an Ecore type filter, the media will blow out between the wide open center cage windows - probably quite easily. The can of the filter is much stronger than the element, and may not show any signs of an over pressure event. Also, damage to the element can take mere seconds if the conditions of failure are right ... like a failed pressure regulator on a cold morning start-up

 

[ZeeOSix]

Originally Posted By: yonyon
Originally Posted By: Garak
More precisely, can it handle the flow if an oil pump's relief fails?


Fram and Affinia both say that it can't. I think it should be safe to assume Affinia has done some testing with Wix filters.


I'd like to hear more about this.

 

[mechanicx]

Originally Posted By: Garak
Originally Posted By: mechanicx
So there would not be significant filter element psid.


Very useful pictures. What I'm thinking, and I could be certainly off base with this - others please correct me if I'm wrong - is the following. I'm thinking that the oil pump relief fails and is sending a large volume of high pressure oil into the filter. Of course, it's too much to go through the filter media at full flow, and the bypass is tripped and functions correctly.

However, the oil flow and pressure are still way too much. While a filter in bypass can allow much more oil through, there are limits. It cannot pass an infinite amount of oil nor pass infinite pressure. The pressure and flow get too high, and we have things getting distorted, or even the can blowing out.

What I'm saying is that the bypass in the filter is designed with a couple scenarios in mind. If the filter is clogged, bypass can save the day. If it's a very cold morning and the oil is thick, the bypass will again save the day.

However, these scenarios are based upon the filter and its bypass being subjected to what we would consider normal oil pressure fluctuations, based upon what the filter manufacturer would expect with very cold, thick oil or clogged media.

They wouldn't be based upon the expectation that a pump's relief has failed and is pumping way too much oil at way too high a pressure. The can and the internal structure itself obviously has limitations upon the force they can withstand before failure. For one, a bypass valve in the filter allows for oil to flow without forcing it through the media. However, the bypass doesn't completely isolate the media from the flow - it's not a valve diverting the flow to a completely new fluid circuit thereby protecting the internals of the filter and the can itself.

Basically, the filter can only withstand so much pressure before failure, bypass incident or not. Unless the bypass actually bypasses the filter assembly completely, we are limited but the structural limitations of the filter itself, right?


Yes I'm saying the same thing except that I'm saying that the bypass which feeds into the inside of the filter element would for the most part equalize internal pressure to what's outside the filter element IF it is sized to flow the same as the filter inlet.

Even with the oil pump pressure regulator closed, the oil pump will put out it's maximum but a finite volume. The pressure will rise to a certain level and could blow out the can or gasket, but still will not necessarily crush the the center tube unless there is enough pressure differential. For there to be pressure differential on the inside of the element the bypass has to be restrictive. Unless the bypass is restrictive, increased oil pressure and volume will not increase pressure differential. In other words, increasing pressure alone doesn't alone make the bypass restrictive, the size of the bypass does. If the bypass is restrictive, then yes increasing the pressure will increase the pressure differential.

Bypasses may or may not be restrictive, but just saying higher oil pressure makes them restrictive doesn't seem correct.

Imagine for simplicity, you have an engine with a filter mounting pad and 3/8" oil feed and next to it a 3/8" bypass. Imagine the filter is replaced with a plate. Whether the oil pressure is 80 or 300 psi the pressure in the feed and bypass would be the same. (And the pressure is being created by engine bearings downstream from the bypass)

1. In order to crush the center tube there must be enough psiD, perhaps as much as 80 psi.
2. In order to be psiD the bypass has to be restrictive relative the inlet
3. Increasing flow volume and pressure alone doesn't make the bypass more restrictive, only the relative sizes of the inlet and bypass do.

It's pretty simple, either a bypass is restrictive because of its size and resistance to flow or it's not restrictive. But increasing the pressure doesn't make a properly sized bypass restrictive.

 

[ZeeOSix]

Originally Posted By: mechanicx

I'm saying that the bypass which feeds into the inside of the filter element would for the most part equalize internal pressure to what's outside the filter element IF it is sized to flow the same as the filter inlet.


Yes ... possibly IF it was designed (ie, sized right) to accommodate a huge slug of cold thick oil from an oil pump with no pressure/volume regulation. I don't think you're going to find many filters that will survive a situation like that with no damage at all. The cold oil factor is a very important aspect in the failure mode. The colder and thicker the oil is, the more likely the bypass valve isn't going to save the element if the oil pump pressure regulator fails.

Originally Posted By: mechanicx

Even with the oil pump pressure regulator closed, the oil pump will put out it's maximum but a finite volume.


The output flow is only "finite" at max engine RPM. A positive displace oil pump with no pressure regulation will basically keep putting out linearly increasing volume output with RPM. So if it's putting out 2 GPM at 1000 RPM, it's putting out 12 GPM at 6000 RPM (if the pump clearances are tight).

When the pressure regulator fails, the oil pump can't control output pressure based on the viscosity factor. So if the oil pump puts out 4 GPM at 2000 RPM, then it's also going to put out 4 GPM at 2000 PRM regardless if the oil is thick as honey or thin as water.

Originally Posted By: mechanicx

The pressure will rise to a certain level and could blow out the can or gasket, but still will not necessarily crush the the center tube unless there is enough pressure differential. For there to be pressure differential on the inside of the element the bypass has to be restrictive.


"Restrictive" is relative. The bypass may not be very restrictive to flowing 4 GPM of hot thin oil, but it could be very restrictive to flowing 4 GPM of thick cold oil. If it is, the PSID will increase significantly, and the weak link in the construction (the center tube/media) will fail first.

Also keep in mind that if this high flow and high pressure condition happens quickly, like at a very cold start-up, that the bypass valve may not react quick enough to the "shock wave" so to speak that would hit the filter first. Element damage could occur much quicker than the bypass valve can react ... especially of the guy start revving the motor high before the oil thins down some. There are a lot of factors involved besides just the "size of the bypass valve".

 

[mechanicx]

You mention "cold, thick oil" increasing pressure, but you fail to mention that a positive displacement pump will not pump as much volume of cold, thick oil from the sump. If oil becomes really cold and thick enough it won't pump from the sump at all. And that cold, thick oil is going to create the same higher resistance going into the oil filter inlet feed as the bypass feed if the bypass is of equal or larger area.

Why can't you just admit that two passages, a filter inlet and a filter bypass, can have the same area and so operate at the same pressure? Therefore one is not restrictive versus the other, and all this talk about cold, thick oil and pressure regulators are irrelevent side issues.

Quote:
"Restrictive" is relative. The bypass may not be very restrictive to flowing 4 GPM of hot thin oil, but it could be very restrictive to flowing 4 GPM of thick cold oil. If it is, the PSID will increase significantly, and the weak link in the construction (the center tube/media) will fail first.


It's relative only because the filter inlet side's pressure will increase due to the cool, thick oil or decrease if the oil is warm and thin, just as it will at the bypass. If the bypass has no restriction in relation to the filter feed with thin oil at lower volume, it shouldn't have relative restriction with thicker oil and higher volume.

Quote:
Also keep in mind that if this high flow and high pressure condition happens quickly, like at a very cold start-up, that the bypass valve may not react quick enough to the "shock wave" so to speak that would hit the filter first. Element damage could occur much quicker than the bypass valve can react ... especially of the guy start revving the motor high before the oil thins down some. There are a lot of factors involved besides just the "size of the bypass valve".


If this were really the case that bypass have trouble opening, filters would likely fail regularly on cold start ups even if the pressure regulator was working.

 

[yonyon]

Originally Posted By: ZeeOSix
Originally Posted By: yonyon
Originally Posted By: Garak
More precisely, can it handle the flow if an oil pump's relief fails?


Fram and Affinia both say that it can't. I think it should be safe to assume Affinia has done some testing with Wix filters.


I'd like to hear more about this.


I believe there was a video from Fram posted to this thread (was it this thread?) with such a statement in it. For the same from Affinia, just look inside an old Wix filter catalog. It's in there.

 

[ZeeOSix]

Originally Posted By: mechanicx
You mention "cold, thick oil" increasing pressure, but you fail to mention that a positive displacement pump will not pump as much volume of cold, thick oil from the sump. If oil becomes really cold and thick enough it won't pump from the sump at all.


You got proof of that? ... or just conjecture on your part (heard that before

) . I'm talking around 30 deg F like the guy in the video mentioned, and even conventional oil will flow pretty good at that temperature. Maybe at some point when the oil can barely flow that might happen, but not at less extreme temps. Again, we are talking about a scenario where there is no oil pump pressure regulation. The main focus here is that the PD pump could put out significantly more cold oil flow than if the pressure regulator was functioning correctly.

Originally Posted By: mechanicx

And that cold, thick oil is going to create the same higher resistance going into the oil filter inlet feed as the bypass feed if the bypass is of equal or larger area.


Again ... what determines if a filter gets destroyed or not from a failed pump regulator depends on IF the bypass valve can handle the increased flow and viscosity factor. Just because you keep trying to make the argument that if the bypass is sized the same as the filter inlet/outlet, that doesn't automatically mean there is low PSID across the media in a runaway pump output situation.

Originally Posted By: mechanicx

Why can't you just admit that two passages, a filter inlet and a filter bypass, can have the same area and so operate at the same pressure? Therefore one is not restrictive versus the other, and all this talk about cold, thick oil and pressure regulators are irrelevent side issues.


Same answer as above. Just because they are the same size doesn't guarantee that the bypass valve will save the filter if the flow is thick and large.