Cut open a Purolator Classic.....

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I cut open a Purolator Classic L14610 today, very uniform pleats, nice endcaps, metal crimped seam, but my goodness, the bypass valve. It was almost rock hard! I cant imagine the oil pressure needed to open that thing. The valve on the OEM Honda filter and Fram TG were easily opened by my thumb. Definitely not within Honda specs. That is what really turns me off this filter, that and the nitrile ADBV (which should be a non issue for a short OCI). Anyway what gives, is that acceptable? I can post the pics if anyone likes.
 
Can you post pictures? I've never seen a Purolator bypass that didn't open correctly. In fact, if it does indeed not open correctly, Purolator will want to know about it; call their customer support phone number. I know an engineer at Purolator; PM me if you can't get help from their customer support number.
 
The flat spring bypass valve design has been thrashed over a few times here. I'm sure it opens at the PSI spec that Purolator advertises for that filter.
 
Originally Posted By: Hokiefyd
Can you post pictures? I've never seen a Purolator bypass that didn't open correctly. In fact, if it does indeed not open correctly, Purolator will want to know about it; call their customer support phone number. I know an engineer at Purolator; PM me if you can't get help from their customer support number.


It opens, but it takes a LOT of pressure. WAY more than the Honda OEM or TG I recently cut open. And yes I will post pics if you like.
 
Last edited:
Originally Posted By: ZeeOSix
The flat spring bypass valve design has been thrashed over a few times here. I'm sure it opens at the PSI spec that Purolator advertises for that filter.


Do you know what the spec is? for that particular filter?
 
I opened an L20195 in April and the bypass does seem hard to press, but I'm sure they are thoroughly tested over the years and that's just the way it is for this design.

2hoiibd.jpg
 
Originally Posted By: MrQuackers
I opened an L20195 in April and the bypass does seem hard to press, but I'm sure they are thoroughly tested over the years and that's just the way it is for this design.

2hoiibd.jpg



Yes but the harder it is to press the more oil pressure it will take to open it up, possibly starving the engine of oil. Plus Hondas spec must be lower as the Honda OEM filters I have cut open have the bypass valve open with very little pressure. Press it with your thumb and there is little resistance, press the Purolator L14610 bypass valve and it takes two hands with full force and it barely opens.
 
I have cut open a few filters and I noticed how hard it was to try and open the by-pass on a Purolator. It was either a L30001 or an L14670,both have the same by-pass rating which is 8-16 psi.They may open but maybe they open at the higher end of their limit.

The by-pass in the filters I mentioned are not like those in the pic but have a spiral shaped flat spring.

The Driveworks filter from AAP is rated at 8-18 psi.

The Fram version is rated at 12 psi.

The Affinia/WIX version is rated at 8-11 psi.

It seems that Purolator has a higher limit than most of the filters I mentioned above,this may or may not apply to all Puro filters.
 
Originally Posted By: gregk24

Yes but the harder it is to press the more oil pressure it will take to open it up, possibly starving the engine of oil. Plus Hondas spec must be lower as the Honda OEM filters I have cut open have the bypass valve open with very little pressure. Press it with your thumb and there is little resistance, press the Purolator L14610 bypass valve and it takes two hands with full force and it barely opens.


It all depends on how much AREA (in square inches) there is on the bypass valve. If you measure & calculate the area, and also measure how much force it takes to crack the valve open, then you can calculate the PSI that is needed to crack it open.

If the valve was designed to open at say 14 PSI, and the area of the valve is large, it will feel like it takes more force to open than if the area was smaller. The spring stiffness is designed to make the valve open at the right PSI based on the area of the valve that the oil delta pressure is acting on. The larger the pressure area, the stiffer the spring.

Force = PSI x Area

PSI = Force/Area
14 = 20/1.429 14 = 10/0.713
I bet the area on those Honda filters is small than on the L14610, and maybe Honda uses a lower bypass setting too. Gotta look at all factors involved in the design of a bypass valve.

The smaller the area, the more PSI will be required to make the valve move.

This has been done before and it come out close to what Purolator advertises. You're just judging by "feel", and is this case it's deceiving.
 
Originally Posted By: motorguy222
According to Puro,the by-pass rating for the L14610 is 14-18 psi.


Thats high! is it not? Does anyone know the TG 7317 bypass rating?
 
Originally Posted By: gregk24
Originally Posted By: motorguy222
According to Puro,the by-pass rating for the L14610 is 14-18 psi.


Thats high! is it not? Does anyone know the TG 7317 bypass rating?


It also depends on the design of the filter ... not just the vehicle it's going on.

In other words, 10 different filter brands specified for the same exact vehicle may not all have the same bypass valve setting.
 
Why not post the pics up in this thread ... it's about the valve anyway.

You have a force gauge laying around? If so, measure how much force is need to make the valve move, then measure the diameter and calculate the area. PSI = Force/Area.

If the bypass valve was 1 inch in dia, it would take 14 lbs of force on the center of the disk to make it crack if the setting is 14 PSI. You have to measure, not guess by how "stiff" it feels.
 
Is 14-16 psi high for a deltaP? Perhaps ...

But considering your deltaP probably never gets anywhere near that, ever, in the first place, then I'd not sweat it.

Some folks worry about the media blowing out, and therefore might want a very small deltaP bypass rating.

Others fret over particulate doing an end-run via the bypass because the deltaP is too low.

There are still others of us that realize deltaP large enough to trip the bypass is a very rare occurrence, and we don't worry about it.

This is similar to the concept of oil vis; we want it as thick as necessary and as thin as possible. When it comes to bypass settings, I want them as low as practical and as strong as needed. Of all the engines I've owned and operated over the years, I've have never, ever had a piece of equipment fail due to the bypass setting ....

To each his own.
 
Originally Posted By: dnewton3
But considering your deltaP probably never gets anywhere near that, ever, in the first place, then I'd not sweat it.

There are still others of us that realize deltaP large enough to trip the bypass is a very rare occurrence, and we don't worry about it.

Of all the engines I've owned and operated over the years, I've have never, ever had a piece of equipment fail due to the bypass setting ....

To each his own.
Once again, the voice of reason.

I do have to admit, though, that having this forum where people can and do question things like this has lead to a much better understanding of lubrication and filtration for the common man such as myself.

The downside is that I was much happier when I was ignorant and didn't spend hours agonizing whether to use PP or QSUD for my next OCI...

I hate you all.
 
Originally Posted By: RF Overlord
Originally Posted By: dnewton3
But considering your deltaP probably never gets anywhere near that, ever, in the first place, then I'd not sweat it.

There are still others of us that realize deltaP large enough to trip the bypass is a very rare occurrence, and we don't worry about it.

Of all the engines I've owned and operated over the years, I've have never, ever had a piece of equipment fail due to the bypass setting ....

To each his own.
Once again, the voice of reason.

I do have to admit, though, that having this forum where people can and do question things like this has lead to a much better understanding of lubrication and filtration for the common man such as myself.

The downside is that I was much happier when I was ignorant and didn't spend hours agonizing whether to use PP or QSUD for my next OCI...

I hate you all.




+1 I hate you all too, as if I wasn't OCD enough already haha.

But seriously ever since I've learned of this site/started doing my own oil changes, nothing have been on my cars except purolators, and no issues yet. I think the classic and pureones are the best bang for buck in there respective fields.

However I won't lie, the higher bypass rating does bother me, but then again the engineers at purolator probably know at least a little more about oil filters than me
grin.gif
 
I suspect my recent tour of failed experiments regarding the double ADBV filters may in fact be due to the much higher bypass settings on them. Both BOF and I were getting intermittent start up noise with them and we shouldn't have been.

Makes me wonder if my beloved FL-400s or Tough Guards are actually going into at least partial bypass at start up.
 
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