Is there any evidence to support the theory of a dome end bypass valve allowing trapped contaminates to wash back through the engine when an oil filter by chance goes into bypass? Facts or opinions accepted.
Thread End vs Dome End Bypass?
- Thread starter 4ever4d
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Motorcraft seems to think so -- Motorcraft Cutaway
One thing though, are not the majority of filters dome end bypass? Therefore, your choices are somewhat limited from the onset?
One thing though, are not the majority of filters dome end bypass? Therefore, your choices are somewhat limited from the onset?
The Motorcraft vid is what prompted me to delve into this issue and yes the majority of filters are dome end bypass, Motorcraft and Wix the exclusions.
Is the sacrifice of media area = or <> the risk of backwash in the occasion of a bypass situation?
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In my mind i can see the point of a thread end bypass being better as pertaining to backwash contaminates, but with a loss of media surface it may not be ideal or a good trade off as the filtering ability may suffer. I suppose in the end more surface area is better as how often does a filter reach bypass pressure to begin with? Not often i would say, if ever.
There is a serious impact on the amount of filter media for the same size filter. Perhaps it's more of an advantage to have the filter media, and maybe never go into bypass as a result from the extra "flow" capability? I have also heard that a filter can go into bypass on every start, or every winter start at least, so maybe a "better" bypass would be better?
Originally Posted By: SOHCman
There is a serious impact on the amount of filter media for the same size filter. Perhaps it's more of an advantage to have the filter media, and maybe never go into bypass as a result from the extra "flow" capability? I have also heard that a filter can go into bypass on every start, or every winter start at least, so maybe a "better" bypass would be better?
It could certainly be more of an issue in colder climates on cold starts.
There is a serious impact on the amount of filter media for the same size filter. Perhaps it's more of an advantage to have the filter media, and maybe never go into bypass as a result from the extra "flow" capability? I have also heard that a filter can go into bypass on every start, or every winter start at least, so maybe a "better" bypass would be better?
It could certainly be more of an issue in colder climates on cold starts.
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Originally Posted By: 4ever4d
The Motorcraft vid is what prompted me to delve into this issue and yes the majority of filters are dome end bypass, Motorcraft and Wix the exclusions.
I am assuming not all WIX are either...I know the one for my FX4 is dome end bypass as is the one for my daughter's Elantra.
I did not realize there was much of a sacrifice of media area (I am only speaking of the MC FL820s versus the P1 equivalent); I cut each of them open and (although I am certain I could have missed it) a vast difference in media size did not jump out at me.
The Motorcraft vid is what prompted me to delve into this issue and yes the majority of filters are dome end bypass, Motorcraft and Wix the exclusions.
I am assuming not all WIX are either...I know the one for my FX4 is dome end bypass as is the one for my daughter's Elantra.
I did not realize there was much of a sacrifice of media area (I am only speaking of the MC FL820s versus the P1 equivalent); I cut each of them open and (although I am certain I could have missed it) a vast difference in media size did not jump out at me.
Originally Posted By: 2010_FX4
Originally Posted By: 4ever4d
The Motorcraft vid is what prompted me to delve into this issue and yes the majority of filters are dome end bypass, Motorcraft and Wix the exclusions.
I am assuming not all WIX are either...I know the one for my FX4 is dome end bypass as is the one for my daughter's Elantra.
I did not realize there was much of a sacrifice of media area (I am only speaking of the MC FL820s versus the P1 equivalent); I cut each of them open and (although I am certain I could have missed it) a vast difference in media size did not jump out at me.
I suppose it depends on the filter design. Everything i have seen points to a good loss of media for thread end filters. May not always be the case.
Originally Posted By: 4ever4d
The Motorcraft vid is what prompted me to delve into this issue and yes the majority of filters are dome end bypass, Motorcraft and Wix the exclusions.
I am assuming not all WIX are either...I know the one for my FX4 is dome end bypass as is the one for my daughter's Elantra.
I did not realize there was much of a sacrifice of media area (I am only speaking of the MC FL820s versus the P1 equivalent); I cut each of them open and (although I am certain I could have missed it) a vast difference in media size did not jump out at me.
I suppose it depends on the filter design. Everything i have seen points to a good loss of media for thread end filters. May not always be the case.
And the real point.....can anyone even show that any engine has ever suffered and shown shorter longevity running either type of bypass?? Sometimes we spend so much time on this stuff when in reality it really makes no difference whatsoever to the vast majority of drivers and engines. Change the oil regularly (your choice on OCI) and you'll be fine!
I don't believe it matters, and here's why. Just before the bypass valve opens (assume dome-end), there is a large (equal to the bypass relief value) pressure differential across the filter media, forcing the dirt particles hard into the media and trapping them there. Once the bypass begins to open, the pressure differential across the filter media stops increasing, but it DOES NOT DECREASE. Therefore as long as the bypass valve is open, there is a huge force holding all the trapped dirt right where it is. The comparatively small force of the bypassing oil flowing across the media from base-to-dome is not going to overcome the force holding the grit against the media.
That's my theory, and I'm stickin' to it.
That's my theory, and I'm stickin' to it.
As for which is more common, you can quickly spot dome-end bypass filters just by looking down the center hole. Its my non-scientific guesstimate that I've seen a whole lot more base-end bypass than dome-end bypass. The PureOne sized for the normally-aspirated Chrysler EDZ engine is base-end-bypass, but the slightly longer one for the turbocharged EDZ is dome-end (I run this on my wife's N/A PT for the extra filter media area).
Originally Posted By: 440Magnum
I don't believe it matters, and here's why.
I'm with you on this. I drive a lot of Fords and I use a lot of Motorcraft and Wix filters. However, if they are on sale, I will not avoid a FAR filter, a Purolator, a Quaker State (depends on the application) or the old Supertech E-core filters. I do change my oil sooner than a lot of drivers on this board, so maybe that's why I'm really not afraid if the bypass occasionally does open up.
To me, it's a selling point for the manufacturer, but not an engine death sentence if I buy some other brand.
I don't believe it matters, and here's why.
I'm with you on this. I drive a lot of Fords and I use a lot of Motorcraft and Wix filters. However, if they are on sale, I will not avoid a FAR filter, a Purolator, a Quaker State (depends on the application) or the old Supertech E-core filters. I do change my oil sooner than a lot of drivers on this board, so maybe that's why I'm really not afraid if the bypass occasionally does open up.
To me, it's a selling point for the manufacturer, but not an engine death sentence if I buy some other brand.
Originally Posted By: 440Magnum
I don't believe it matters, and here's why. Just before the bypass valve opens (assume dome-end), there is a large (equal to the bypass relief value) pressure differential across the filter media, forcing the dirt particles hard into the media and trapping them there. Once the bypass begins to open, the pressure differential across the filter media stops increasing, but it DOES NOT DECREASE. Therefore as long as the bypass valve is open, there is a huge force holding all the trapped dirt right where it is. The comparatively small force of the bypassing oil flowing across the media from base-to-dome is not going to overcome the force holding the grit against the media.
That's my theory, and I'm stickin' to it.
I agree with everything you said above ... but the only caveat is "if" there was a slug of debris/sludge actually laying in the dome end with the filter orientated with base up (like shown in the Motorcraft slide show link), then it's possible that debris cold get swept through the bypass valve if it opened on a start up. Not sure how plausible that scenario really is ... but apparently Ford thinks it happens enough to specify a base end bypass valve. I'm assuming at one time, most Ford engines had filters mounted in the base up orientation.
But yeah, once the debris is captured deep inside the pleats, there will always be fluid pressure pushing the debris against the media and it really can't move around.
I don't believe it matters, and here's why. Just before the bypass valve opens (assume dome-end), there is a large (equal to the bypass relief value) pressure differential across the filter media, forcing the dirt particles hard into the media and trapping them there. Once the bypass begins to open, the pressure differential across the filter media stops increasing, but it DOES NOT DECREASE. Therefore as long as the bypass valve is open, there is a huge force holding all the trapped dirt right where it is. The comparatively small force of the bypassing oil flowing across the media from base-to-dome is not going to overcome the force holding the grit against the media.
That's my theory, and I'm stickin' to it.
I agree with everything you said above ... but the only caveat is "if" there was a slug of debris/sludge actually laying in the dome end with the filter orientated with base up (like shown in the Motorcraft slide show link), then it's possible that debris cold get swept through the bypass valve if it opened on a start up. Not sure how plausible that scenario really is ... but apparently Ford thinks it happens enough to specify a base end bypass valve. I'm assuming at one time, most Ford engines had filters mounted in the base up orientation.
But yeah, once the debris is captured deep inside the pleats, there will always be fluid pressure pushing the debris against the media and it really can't move around.
Originally Posted By: 4ever4d
In my mind i can see the point of a thread end bypass being better as pertaining to backwash contaminates, but with a loss of media surface it may not be ideal or a good trade off as the filtering ability may suffer.
I suppose it matters when one looks at the size of the filter in the first place. Bill has some pics in this oil filter forum comparing a small Wix (like I use) to a small Purolator, I believe, the former having the thread end bypass and the latter having the dome end bypass. In a small filter, it makes a significant difference. For my application, I use Wix because of availability, but Bosch is my preference due to its price being about half that of the Wix, and has the dome end and correspondingly larger filtering area, but I must order them online.
In comparing a thread end 51515 or FL1A to a base end equivalent, I doubt it would make as much of a difference. Over the years, I've owned a lot of Fords and tend to stick with thread end bypass simply due to my usage of Motorcraft and Wix (most of which are thread end, but not all).
In any case, it might matter if one is loading up the filter in the first place. Under conservative OCIs, will it make a difference?
In my mind i can see the point of a thread end bypass being better as pertaining to backwash contaminates, but with a loss of media surface it may not be ideal or a good trade off as the filtering ability may suffer.
I suppose it matters when one looks at the size of the filter in the first place. Bill has some pics in this oil filter forum comparing a small Wix (like I use) to a small Purolator, I believe, the former having the thread end bypass and the latter having the dome end bypass. In a small filter, it makes a significant difference. For my application, I use Wix because of availability, but Bosch is my preference due to its price being about half that of the Wix, and has the dome end and correspondingly larger filtering area, but I must order them online.
In comparing a thread end 51515 or FL1A to a base end equivalent, I doubt it would make as much of a difference. Over the years, I've owned a lot of Fords and tend to stick with thread end bypass simply due to my usage of Motorcraft and Wix (most of which are thread end, but not all).
In any case, it might matter if one is loading up the filter in the first place. Under conservative OCIs, will it make a difference?
odd napa gold has 2 less pleats than wix?
Originally Posted By: 440Magnum
I don't believe it matters, and here's why. Just before the bypass valve opens (assume dome-end), there is a large (equal to the bypass relief value) pressure differential across the filter media, forcing the dirt particles hard into the media and trapping them there. Once the bypass begins to open, the pressure differential across the filter media stops increasing, but it DOES NOT DECREASE. Therefore as long as the bypass valve is open, there is a huge force holding all the trapped dirt right where it is. The comparatively small force of the bypassing oil flowing across the media from base-to-dome is not going to overcome the force holding the grit against the media.
That's my theory, and I'm stickin' to it.
Good and sound reasoning here and goes a long in helping with my thoughts on the issue. Thanks.
I don't believe it matters, and here's why. Just before the bypass valve opens (assume dome-end), there is a large (equal to the bypass relief value) pressure differential across the filter media, forcing the dirt particles hard into the media and trapping them there. Once the bypass begins to open, the pressure differential across the filter media stops increasing, but it DOES NOT DECREASE. Therefore as long as the bypass valve is open, there is a huge force holding all the trapped dirt right where it is. The comparatively small force of the bypassing oil flowing across the media from base-to-dome is not going to overcome the force holding the grit against the media.
That's my theory, and I'm stickin' to it.
Good and sound reasoning here and goes a long in helping with my thoughts on the issue. Thanks.
Friend cut open the FL400S and the purolator equivlent, the L20195. The L20195 would have had the same element length as the FL400S had they shrank it down to the new size, as the can is less than half a inch smaller.
I switched to the L20195 from the FL400S mostly for cost, 3.27 vs 3.97 a filter. Same basic filter just the bypass is on the opposite end, and it is the original FL400 size, not the newer FL400S/FL2005 hybrid that is on my car now. My 2003 sable is not picky on the antidrainback or bypass valves, as it is a 1980s design for the engine, with a horizontal filter, i doubt it needs as good of a drainback valve or bypass as a duratec, or SHO.
I switched to the L20195 from the FL400S mostly for cost, 3.27 vs 3.97 a filter. Same basic filter just the bypass is on the opposite end, and it is the original FL400 size, not the newer FL400S/FL2005 hybrid that is on my car now. My 2003 sable is not picky on the antidrainback or bypass valves, as it is a 1980s design for the engine, with a horizontal filter, i doubt it needs as good of a drainback valve or bypass as a duratec, or SHO.
Originally Posted By: 440Magnum
I don't believe it matters, and here's why. Just before the bypass valve opens (assume dome-end), there is a large (equal to the bypass relief value) pressure differential across the filter media, forcing the dirt particles hard into the media and trapping them there. Once the bypass begins to open, the pressure differential across the filter media stops increasing, but it DOES NOT DECREASE. Therefore as long as the bypass valve is open, there is a huge force holding all the trapped dirt right where it is. The comparatively small force of the bypassing oil flowing across the media from base-to-dome is not going to overcome the force holding the grit against the media.
That's my theory, and I'm stickin' to it.
Continue to stick. It's a good theory. Good chance it's fact, I think. It's probably not an absolute, though ... but then few things are. It's the best reason I've heard for the preponderance of the dome end bypass in the market. Ford specs it for their own reasons but we know the OEMs sometimes have "legacy opinions" on the ways they spec things.
I don't believe it matters, and here's why. Just before the bypass valve opens (assume dome-end), there is a large (equal to the bypass relief value) pressure differential across the filter media, forcing the dirt particles hard into the media and trapping them there. Once the bypass begins to open, the pressure differential across the filter media stops increasing, but it DOES NOT DECREASE. Therefore as long as the bypass valve is open, there is a huge force holding all the trapped dirt right where it is. The comparatively small force of the bypassing oil flowing across the media from base-to-dome is not going to overcome the force holding the grit against the media.
That's my theory, and I'm stickin' to it.
Continue to stick. It's a good theory. Good chance it's fact, I think. It's probably not an absolute, though ... but then few things are. It's the best reason I've heard for the preponderance of the dome end bypass in the market. Ford specs it for their own reasons but we know the OEMs sometimes have "legacy opinions" on the ways they spec things.
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I just got off the phone with an engineering contact at a well known corporation known for filtration. His specialty is engine oil filtration and I can only repeat what he said if he stays anonymous. He is one of my regular sources for my work and I want to protect the relationship. You can either trust me that I am accurately relaying his comments or not.
1- The biggest time to worry about bypass is a cold start because that's when all the junk in the canister has settled to the bottom and it's also the time when the DeltaP will be high enough to pop the bypass valve. FOr the most part, what was said above is true about the junk being held in the media when oil is flowing, but some will fall off and settle when the engine is shut off.
1A- Obviously the location of the bypass versus that settling point will indicate how much junk will get sucked up if the filter bypasses in the above cold start scenario. My source agreed that on a horizontally mounted filter, there isn't much difference in the amount of junk that potentially will be sucked up between a dome and threaded end bypass.
2- He said that "generally" a threaded end bypass is slightly better in most applications BUT he also said that there have been a lot of functional problems with the dome end valves on the market sticking open. He says it comes down to cost. The example he used is that it takes a $1.50 to make a threaded end valve that will equal the reliability of a $0.50 dome end valve. From there, you do the math.
3- My biggest question has always been how often does the average filter bypass. He chuckled at that and said something like "We'd all like to know that."
You can predict the most likely time this can happen but there are too many variables to make a general rule. As little as possible is the goal. He commented that bypass events are overall more likely at the end of filter life, when the unit is loaded and will have a higher DeltaP. Another comment was that here in the USA, we tend to engineer for higher filter efficiency and a shorter OCI, knowing the filter will be changed before the bypass events become excessive. In Europe, they prefer fewer potential bypass events, so generally have less efficiency, and longer OCIs. They also run higher viscosities and lower efficiencies are an aid in preventing bypasses in that event as well. He did quote an average that here in the USA, the average filter is changed with 45 percent life remaining but he didn't give me the source for that.
1- The biggest time to worry about bypass is a cold start because that's when all the junk in the canister has settled to the bottom and it's also the time when the DeltaP will be high enough to pop the bypass valve. FOr the most part, what was said above is true about the junk being held in the media when oil is flowing, but some will fall off and settle when the engine is shut off.
1A- Obviously the location of the bypass versus that settling point will indicate how much junk will get sucked up if the filter bypasses in the above cold start scenario. My source agreed that on a horizontally mounted filter, there isn't much difference in the amount of junk that potentially will be sucked up between a dome and threaded end bypass.
2- He said that "generally" a threaded end bypass is slightly better in most applications BUT he also said that there have been a lot of functional problems with the dome end valves on the market sticking open. He says it comes down to cost. The example he used is that it takes a $1.50 to make a threaded end valve that will equal the reliability of a $0.50 dome end valve. From there, you do the math.
3- My biggest question has always been how often does the average filter bypass. He chuckled at that and said something like "We'd all like to know that."
You can predict the most likely time this can happen but there are too many variables to make a general rule. As little as possible is the goal. He commented that bypass events are overall more likely at the end of filter life, when the unit is loaded and will have a higher DeltaP. Another comment was that here in the USA, we tend to engineer for higher filter efficiency and a shorter OCI, knowing the filter will be changed before the bypass events become excessive. In Europe, they prefer fewer potential bypass events, so generally have less efficiency, and longer OCIs. They also run higher viscosities and lower efficiencies are an aid in preventing bypasses in that event as well. He did quote an average that here in the USA, the average filter is changed with 45 percent life remaining but he didn't give me the source for that.
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