It does act like a spring, so it is a spring in function, because it's designed to flex under force which puts pressure on the end cap to hold all the guts of the filter tightly together. Filters that don't use a "leaf spring" design use a metal coil spring to do the same thing.
Virgin FE7317 cut open w/light to bypass seal area.
- Thread starter Sayjac
- Start date
I certainly does have spring tension ... that's what holds all the guts tightly together inside the can when assembled.
garageman402
$100 Site Donor 2024
I disagree that it has spring tension, unless you are referring to the tension in regular steel under stress. Take for example a U bolt muffler clamp. It holds the pipe joint together under pressure, yet no spring action is involved, unless you count the lock washer as spring tension.
The spring effect in the bracket could explain why there is light getting through when it is relaxed after disassembly. The can is holding it in & down effectively keeping flat pressure on the filter guts, then when relaxed it forms the arch we see when Pete tries to push it into the end cap. The spring tension is from the ADBV at the other end being compressed. @Glenda W. may be onto something by comparing it to a crush washer which will not revert to its original shape after being decompressed. But then an exhaust pipe won't revert either.
garageman402
$100 Site Donor 2024
At least you can look inside & see the wire backing through the holes. If/when they start using the louvered tubes, you won't even be able to do that.......
I’m a little confused on the amount of “internal” spring tension applied to the filter body as installed. If there was substantial “pre-loaded” force against the filter assembly, why wouldn’t we see the outer shell shoot up violently when cut off?
garageman402
$100 Site Donor 2024
OK, there is no spring tension. The only thing that causes things to "shoot up violently" is spring tension, so obviously there is no spring tension. It might pop up slightly but that is the ADBV relaxing. Example: You are pulling something on a forklift with a rope & if the rope breaks it will fly up in your face. If you pull it with a chain & the chain breaks, it will fall down. The forklift might take off, but the chain will drop. Why? No spring tension in the chain.
You can tighten a bolt 200ft/lbs with zero movement, so zero movement of the filter can when it's cut could be equivalent to a few hundred lbs. I said "could" be, but it's probably not. Point is you cannot replicate the pressure applied to the bracket that holds the bypass valve by pushing it into the bench, it will flatten & create an arch. I'm sure Champion has researched it enough to know exactly how much pressure to apply to the can when crimping it to the base plate. Too much, the bracket will bend creating an arch, too little, it won't seal.
It can't ... no spin-on oil filter goes into bypass by lifting the entire element off the base of the filter, if that's what you're describing.
If the surface on the leaf spring that is suppose to sit level on the end cap to "seal" around the center tube it is not completely flat, then no matter how much force is put on the ears of the leaf spring it will not deform and flatten out that sealing surface area. The ears of the leaf spring are what flex/deflect in the assembled filter to put force on the end cap to keep the guts of the filter tight.
The light leak doesn't go away when lots of force is put on the leaf spring assembly, as proven by Whip City and @Sayjac. As mentioned above, you can't deform the area on the leaf spring that contacts the circumference of the center tube on the end cap. Only part of the leaf spring that can flex/deflect are the ears which is what puts the spring force on the filter guts when installed. In order to not get a light leak around the center tube interface, the sealing area needs to be flat and smooth on both the leaf spring and the end cap.
The ears of the leaf spring can flex, and that's where the spring force comes from. They are very stiff, but they do flex enough to produce force to hold the guts of the filter tight.
As already pointed out, no matter how much pressure is put down on the leaf spring, the light gap will not change. That's because you can not deform the leaf spring in the area where the actual sealing surfaces are. Only the ears on the leaf spring can flex, and the ears flexing slightly is what produces the spring force that pushes down on the end cap and keeps the filter gut tight. There might be some slight flex in the ADBV rubber too, but the leaf spring is also flexing under force.
That happens on filter with a coil spring because a coil spring has to be compressed a decent amount of distance to get the force. On a leaf spring, the ears are pretty stiff, so they only need to be deflected a very small amount to get the proper down force on the end cap.
The ears will flex a certain amount before they will permanently deform. So yeah, the designers know how much force can be put on the ears to provide the down force without causing the leaf spring to deform permanently. When a filter is dropped, depending how it lands, it can cause permanent deformation to the leaf spring, which then results in a filter rattling with loose gut.
garageman402
$100 Site Donor 2024
Yes, that is what I was describing, apparently it is wrong, no wonder I couldn't wrap my head around it. Lol
But don't some filters have the bypass at the base instead of the dome end? If so, how does that work? I've heard that being at the dome end, oil can wash debris off of the dirty side of the filter & through the bypass, but that seems pretty much the normal placement these days.
Edit: Never mind, I see you answered that in post# 167
That " horse " sure has some really long ears, for a " horse " . IJS......^^^ Post 90 … All speculation (no real proof of claims) and dead horse hype.
The bypass valve in the base end has it's own spring loaded valve in it - for example the ones used in Wix and Motorcraft filters. Unless it's an ADBV/bypass "combo" valve in the base end, then the rubber combo valve just flexes under pressure to open and allow dirty oil to bypass the element. Whip City shows how the Wix base end bypass valve works.
It could, but unlikely because when oil is flowing through the filter and the bypass valve opens up there is still oil flow going through the media which should prevent any debris in the media from coming off. Debris could slough off the media when the engine is off and collect in the dome end of the filter if it's orientated with the base down.
garageman402
$100 Site Donor 2024
OK, so looking at the pic in post# 96, we see the light is coming from the sides. Does it make sense that if the ears pressed down & forced outward, then the center will be pulled up by the "arms" on the ears? If the ears were to be squeezed back toward the center (laterally) would that force the arms to push the center back down?
It would also seem that the bracket (spring) on filters with no bypass valve would be inherently stronger because there's not a giant hole in the middle of it?
The center area of the leaf spring that contacts the end cap it too stiff to flex, regardless of how much force is put on the ears. The ears will probably permanently bend before the area where the leaf spring contact the end cap deforms in any way. Like mentioned earlier, the problem is that the area where the leaf spring contacts the end cap is just not flat and/or not smooth enough to make a good seal.
As pointed out in another thread (post link below), that leaf spring is make right, and therefore seals well. The leaf spring on this Endurance in this thread isn't made very well ... not flat, thin sealing area and rough surface. That's what matters in order to have a decent metal-to-meal seal.
https://bobistheoilguy.com/forums/t...th-bypass-flashlight-test.386754/post-6999416
Probably, but I think the ones with the bypass valve built in are plenty stiff too. So stiff that putting a bunch of force on the ears will not make the area where it seals at the center tube deflect enough to flatten it out and seal better. The problem with the light leakage issue is that the leaf spring is not formed well in the first place. It needs to be flat and smooth, like the one in the other thread (link posted above).
More chits and giggles pics!
This from video on Super Tech filter. Very dramatic demonstration of BIG TIME failure of flashlight test. Note the very significant “nubs” on the sides of the bypass. They appear to be there to “secure” the valve body in place, However, they result in significant “voids” along the sides, allowing light to pass easily. I think this is instructive in understanding what’s allowing light to pass in other designs similar to this, but not as dramatic. Look closely at the bottom pic and you can spot the nubs protruding.
Again, this begs the question >>>How, if at all, does this impact bottom line filtration efficiency?<<<<<
This from video on Super Tech filter. Very dramatic demonstration of BIG TIME failure of flashlight test. Note the very significant “nubs” on the sides of the bypass. They appear to be there to “secure” the valve body in place, However, they result in significant “voids” along the sides, allowing light to pass easily. I think this is instructive in understanding what’s allowing light to pass in other designs similar to this, but not as dramatic. Look closely at the bottom pic and you can spot the nubs protruding.
Again, this begs the question >>>How, if at all, does this impact bottom line filtration efficiency?<<<<<
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garageman402
$100 Site Donor 2024
Interesting!! This was an FVP filter, he dissected it the following Friday, Lol. I also noticed no gasket between the bypass "unit" & the filter end cap, but probably zero chance of distortion.
4WD
$50 site donor 2025
This picture helps to see the end where you really don’t want a leak. Spring pressure keeps the outer area isolated so that the flow goes through the filter media.
