Virgin FE7317 cut open w/light to bypass seal area.
- Thread starter Sayjac
- Start date
Yeah, that's been posted here more than once before. To be clear, not critiquing the Fram bypass function itself. Fwiw, I think it's fine and works as designed. That video (~2012) would be at time Fram design with seal area either fiber (EG/TG) of the OG XG with non-metal to metal seal area. Topic is a current Champ Labs seal area design.
As an aside, ~12years ago actually met the engineer in the vid Gary Bilski, a good guy. He's also the guy that emphasized that changing the Air Fiter every year (12 months) really only a box recommendation. As AFs (unlike oil) get more efficient with use, in most cases (environment dependent) going longer is preferable. I thought that was cool that he would acknowledge that. I digress.
I did want to add one other observation noted since I removed bypass piece (after posting OP) and put it back. I noticed light coming from under the arms of the stamped spring. I will say, I saw no light coming from either of those areas before it was removed. So at least for me, removing and replacing bypass piece seemed to be a factor in where and amount light seen. Having thought that possibility/variable, why with this c&p I left the bypass piece basically undisturbed for the pic in the OP.
Good info.
My 2 cents ….I’m far from being an engineer, but even if there’s a hint of “daylight” there, It would creep in as minuscule “overflow” as opposed to a forceful gush of bypass oil under pressure when valve is actuated. Also, that small qty “seepage” would eventually get filtered out as well. Could the design be better? Of course, they currently exist in other filters!
It's true, now a very common Champ Labs seal area design. As noted, I found similar light results and posted it with my last c&p of an MP7317. Same CL seal area design. Difference there is, now discontinued MP <$6, and standard ST <$4. Otoh, the topic "premium" FE a $13 filter. While I would prefer not to see it at all, in premium filter imo one should expect better.
Really don't have to be an engineer to understand what's going on here. Similar to a tear found in the media, the light seen means some dirty side (upstream) oil can/will bypass. If that bypass oil, no matter how much, isn't a consideration or concern then using the FE ok for those folks. But, I'm just not one of them.
We’ll, it really boils down to one thing …what’s the overall filter efficiency including any “bypass leakage”? Testing results seem to indicate it’s not a significant issue, design flaws notwithstanding. As you point out…to each his own.
Specs aside, I trust what I see first. The use of of the word "seem" would appear to allow for that. Clearly, you've reached a different conclusion than me, which I allowed in the OP. As accurately stated, to each their own covers it.
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I'd guess the filter media itself is tested for efficiency, not the filter. This oil filter would rate about the same as a filter with a small tear in the media. Not good enough.
BrendanC
$100 site donor 2024
filters are tested as built in the canister per ISO standards. Would be willing to bet that this filter with the “leaky” bypass valve would still test at its rating.
Might as well purchase any filter then, tears don't matter. Anyway you cut it this is a poor design that engineering probably wanted to fix and were overruled by bean counters. Not a product I would ever purchase or use even if it were free.
BrendanC
$100 site donor 2024
so what is your filter of choice right now?
I used to be a big synthetic filter guy, RP or Fram. Now i change my oil more often and use cellulose filters. I like Napa Gold or Wix which have the bypass valve built into the metal end cap. I also use Motorcraft Filters since I can get them cheap and they won't be on too long before the next oil change. I believe they have the best bypass valve design and the media filter efficiency while not the best is good enough for a 3-5K mile OCI. I've seen filter media tears from time to time in most filters, but they are "relatively few". Unfortunately this issue is on every Fram Endurance, RP, Amzoil, and other premium filters with this bypass valve design.
BrendanC
$100 site donor 2024
ahh, now this makes sense. regardless, i would be willing to bet a large sum that the Endurance would test higher than anything you just listed. it is your choice to run the filter you choose however, i believe a “flash light test” is not indicative of how oil will flow through the filter. i wonder how a flash light test would look on a torn cellulose filter.
What we do know is oil flows up to the bypass valve and with enough pressure opens the valve. I don't see how oil wouldn't flow through that bypass valve gap when it isn't open. My thinking is the more people squak about it, the more likely the bypass valve design will change. Hopefully it will..
I'd take that bet. Filter with a visible oil bypass areas testing 99%20um, unlikely imo. In any case, as there's other choices out there with "respectable ratings" no need 'for me' to use one. Fix the seal area design, then yes. Just to be clear again, it's not the bypass valve that's suspect, it's the metal to metal stamped spring to endcap seal area.
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Ascent Filtration tested a Wix XP with the leaky bypass valve that looked fine visually, but failed a bubble point test. What appeared to be a relatively small leak resulted in a lot of bypassed flow. The filter's efficiency peaked at 88% for large particles instead of the expected >99%, implying that over 10% of the oil flow was bypassing the media.
I'll take a stab at doing a pressure drop calculation for a leaky leaf spring seal. If we assume that there's a gap of 0.5 mm around the entire circumference of the seal, the open area comes out to around 31 mm^2. This is a bit larger than the size of a single inlet hole on a typical filter base plate, so it's pretty substantial.
Modelling this as an orifice with an equivalent open area, the flow rate through the leak is 2 GPM when the dP across the media is 0.8 psi. A media dP of 0.8 psi on this filter may require a flow rate through the media of ~3 GPM. The total flow rate through the filter would then be ~5 GPM including the leak. So around 2 GPM / 5 GPM = 40% of the oil flow would bypass the media in this example.
@Sayjac
Are you able to measure the gap with some feeler gauges?
I'll take a stab at doing a pressure drop calculation for a leaky leaf spring seal. If we assume that there's a gap of 0.5 mm around the entire circumference of the seal, the open area comes out to around 31 mm^2. This is a bit larger than the size of a single inlet hole on a typical filter base plate, so it's pretty substantial.
Modelling this as an orifice with an equivalent open area, the flow rate through the leak is 2 GPM when the dP across the media is 0.8 psi. A media dP of 0.8 psi on this filter may require a flow rate through the media of ~3 GPM. The total flow rate through the filter would then be ~5 GPM including the leak. So around 2 GPM / 5 GPM = 40% of the oil flow would bypass the media in this example.
@Sayjac
Are you able to measure the gap with some feeler gauges?
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I'm running a Fram FE3600 currently and will be doing particle count on the next oil sample at 10,000 miles. While I do agree the former Original Ultra design had a lot of forward thinking went into the bypass leaf assembly such as the fiber seal between the metal end cap and leaf spring. There isn't much of an opinion I can say about the new Champ made FE filters without some data to prove it has some larger particles leaking through the leafs spring assembly. Previous particle counts on the related filters (Amsoil & Royal Purple which are the roughly identical to the Fram FE) appears rather impressive if you do some searching around.
No. As noted, since the OP I've removed the bypass from the element for examination and pics so that variable is now not repeatable. Even if it wasn't I have no interest in trying to find and/or create some sort of extrapolation of efficiency based the openings sizes. 'For me' it's very simple, I just won't use one. If others choose to dismiss it out of hand, that's fine, their money and their call.
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The filter Ascent tested in the efficiency test wasn't the same exact filter he bubble tested, so the low efficiency seen may have been with a filter that didn't have a leaky bypass valve. Also, I'd think a dirty oil leak path isn't going to make just certain particle sized particle change ... it should change the efficiency across the whole range of particles.
There's no way the air gap at the bypass to end cap interface it that large. Cut it down to about 20-25% of that would be my estimate because it wasn't a gap all the way around the circumference.
I thought about that and the amount of bypass oil still seems high, 1/2 gallon per minute.