Resurrecting old topic--short center tubes

[guile]

I've read several threads on BITOG that discuss the short center tubes that appear in Purolators and some other oil filters ... I haven't been able to locate any explanations for this apparent defect. See below example for illustration.

Pure One short center tube

I was considering trying a Pure One 14477 for my Camry 2.4l, but after examining one of these filters close up, I'm starting to have reservations about their quality.

 

[XS650]

quote:

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I haven't been able to locate any explanations for this apparent defect.

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Simple, they were out of the correct length tubes when they were assembling that batch of filters.

 

[Big O Dave]

Don't let EK see it, or he'll rip it up in his bare hands:

...it may just be cardboard endcaps that get him going, but I have a feeling that when he sees that short center tube, we'll ALL be seeing green!

 

[labman]

Had my druthers, I would take a full length tube over a short one. On the other hand, I have seen a bunch of reports of short tubes, maybe even a Baldwin of all things over the last year. Still, I haven't seen any reports of collapsed or cut media due to a short tube. It is the sort of thing somebody could happen to notice when they removed a damaged filter. Can't say I always look at mine that closely, but know if it was a big problem, there WOULD be pictures on BITOG.

I think the cartridge elements and now the Ecores with the plastic cage center tubes have proved the media needs less support area that the old metal tubes give. So maybe the short tubes aren't a problem.

 

[kanling]

I don't think it is a defect, it is just the design... for whatever reason.

As long as the media is strong enough to avoid collapse from lack of support, then I say that the short center tube is an improvement. More unblocked flow area.

It certainly is odd, though. I would frankly prefer a full length center tube with more or bigger holes.

 

[ekpolk]

Been there, done that. I was one of the guys challenging the short tubes last year. In fact, I was about to buy a Puro for my car when I noticed this. I balked, as there were other good quality filters with full metal tubes that I could buy just as easily.

What got me going on this, beyond just the uneasy feeling I have about the short tube, is another thread that depicted a partly folded in center tube in an Amsoil filter. My reasoning is that the failure of the similar-sized Amsoil filter, which is built like a tank, was likely caused by an unusual spike in oil pressure, that for whatever reason, was not properly mitigated by the bypass valve. I further figured that if such a condition could cave the metal tube, it could very well blow right through an unsupported segment of filter medium.

A couple further thoughts. First, this is supposition on my part; reasonable I think, but still not based upon scientifically gathered evidence. Second, I readily acknowledge that under normal operating conditions this "short tube" will probably do fine. We're not that I'm aware hearing of a rash of Puro failures. I see it as like seatbelts and airbags. Once in a rare while do they actually come into play, but if you're having an accident, you sure appreciate that you've got the margin of safety they provide. For the same sort of reason, I'd just prefer to have a full-length, anchored, metal center tube.

 

[Beaker74]

Is this shorter center tube in all of the Purolator filters or was this just an isolated batch of filters?

 

[guile]

I examined a few dozen filters in the store (yeah I got some looks) and most had the short tube. I was specifically looking at the Purolator 14477 (premium and Pure One) which fits my engine--2.4l Toyota. All filters for this application had the short tube. I also examined several other sizes, some had the short tube, some didn't.

I suspect this discrepancy (some short, some not) could be for a couple of reasons. As I believe the reduced center tubes can be attributed to cost-cutting measures, either;
1. Regarding the filters that didn't have the shorter center tubes, perhaps I examined old stock
2. In developing this strategy to reduce production costs I assume Purolator conducted a complete analysis ... perhaps the analysis indicated that not all center tubes could be reduced and the oil filter still maintain minimum standards of structural integrity

Of course this is all conjecture on my part.

 

[ekpolk]

quote:

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Is this shorter center tube in all of the Purolator filters or was this just an isolated batch of filters?

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Every single one of the Puro "tall" filters (white and blue cans) that fit the Nissan/Infiniti VQ35 V-6, that I've seen, have the short tube. All of the "thimble" (short) filters have a full length tube. This may have been a temporary thing, but I have yet to see a tall Puro with a full-length center tube.

 

[Beaker74]

Just looked at my Purolator 14476 (Premium Plus and PureOne) for my '97 Camry 2.2L ("thimble" size). Also looked at my 14670 (prem. & P1) & Purolator Maxlife VF16 (both are softball sized) for the '02 van. You're right, ekpolk. No short tubes here.

I have trouble believing that Purolator would do this on purpose. The materials cost savings is minimal. It's only about 1/2 inch short (looking at the above picture). It also removes support from the end of the filter media where it attaches to the end cap.

It's not even a one-size-fits-all tube that goes in all of their filters. That would at least make sense from an inventory mgmt or manufacturing efficiency perspective.

 

[guile]

Looks like I need to forward my question to Purolator. I'll post their reply when I receive it.

 

[guile]

Well, I must say that I'm quite impressed with the quick response from Purolator. I emailed my question to them at 5:57 AM/EST and they replied at 8:05 AM/EST.

My question:


Mr. Duvall,

I recently considered trying a Pure One oil filter (stock # 14477) for my 2005 Toyota Camry (2.4l engine), but after examining one of these filters close up, I'm starting to have reservations about their quality. While reviewing a few dozen Purolator filters in my local auto parts store, I discovered that most had a short center tube; i.e. the center tube doesn't completely extend to the top of the filter.

As stated, I was specifically looking at the Purolator 14477 (premium and Pure One). All filters for this application had the short center tube. I also examined several other sizes, some had the short tube, some didn't. For example, Purolator stock # 14476 (another filter recommended for Toyota 4cyl engines) did not have a short center tube.

This trend has been noted by many other consumers in a myriad of markets throughout the country. Consumers have taken note of this (perceived) defect and are concerned. Can you offer an explanation for our concerns?


Reply from Purolator:

The short centertube in the tall 65 mm filter was a result of part consolidation initiatives.. The tall 65 mm filter simply now uses the centertube from the short 65 mm filter thus eliminating a component part. This change was made about 1 1/2 years ago.

This design was tested extensively before the change was made and the performance of the filter does not suffer in anyway.

Regards,

Richard Hedgepeth
Product Engineering Manager
Arvinmeritor/Purolator


Though I am impressed with their responsiveness to my query ... I'm not as impressed with their explanation.

When they refer to the tall 65mm and the short 65mm I'm assuming that they are referring to filter diameter? Obviously this can't represent height as the "tall" and "short" measurements are equal.

And, "part consolidation initiatives" is definitely a production cost-cutting measure. Not that cost-cutting is always a bad thing, however in this case, my gut-feeling is that this particular initiative by Purolator represents a reduced quality in these specific filters.

 

[Mr Nice]

The Purolator 14610 for Honda also has a short tube. There is nothing to worry about if it has a shorter center tube.

 

[guile]

quote:

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There is nothing to worry about if it has a shorter center tube.

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What leads you to believe the shorter center tubes are not a cause for concern? Intuitively it certainly seems logically to believe the shorter tubes represent a compromise in the structural integrity of the filter ... in comparison to the previous versions with full-length center tubes.

 

[kanling]

Good letter you wrote, guile. And I also like the Purolator response- direct and honest. Not a sham explanation like other manufacturers might use. Cost cutting by reducing parts inventory, plain and simple.

On the 14477 at least, I'm not too worried about the short center tube b/c only 1/2" of element is unsupported and I know the top is glued securely into the end cap.

It is definitely a bit cheesy, though.

 

[kenw]

"What leads you to believe the shorter center tubes are not a cause for concern? "

right back at 'ya: What makes you think they are? I've had enough engineering and 25+ years of experience and I'm dying to find out what you engineering experts think on this matter.....

 

[guile]

quote:

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right back at 'ya: What makes you think they are? I've had enough engineering and 25+ years of experience and I'm dying to find out what you engineering experts think on this matter.....

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I'm certainly not an engineering expert, hence why I prefaced my comment with the word "Intuitively".

quote:

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Intuitively it certainly seems logically to believe the shorter tubes represent a compromise in the structural integrity of the filter ... in comparison to the previous versions with full-length center tubes.

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Based upon common knowledge that corporations do employ production cost-cutting measures while considering relative input prices in order to find the least-cost combination of inputs to produce a given level of output, I believe it's reasonable to assume that Purolator consolidated parts to reduce the costs of the inputs required to produce their filters.

Intuitively, I feel this change reflects a focus on Purolator's "bottom-line" vice improving the quality of their product. Intuitively, I can't believe that the current "shorter tube" version is as sound as the previous "full-length tube" version.

I can't verify this data as I haven't conducted any testing, nor would I be qualified to conduct a test.

Ultimately I do believe that Purolator made the right decision ... strictly from a fiscal viewpoint. Most consumers don't take the time to examine products in as much detail as members of this forum do (case in point; Fram's market success), thus I'm certain the risk assumed by Purolator in making this decision will be offset by the return they realize from reduced production costs.

 

[Beaker74]

"This design was tested extensively before the change was made"

Guess who gets to do the rest of the testing. Definitely a quality issue. Either the filter media needs support for the entire length of the filter or it doesn't. If it doesn't, then Ecore makes more sense because it provides support at both the top & bottom ends. These Purolators leave one of the glued ends flapping in the wind.

 

[ekpolk]

quote:

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"What leads you to believe the shorter center tubes are not a cause for concern? "

right back at 'ya: What makes you think they are? I've had enough engineering and 25+ years of experience and I'm dying to find out what you engineering experts think on this matter.....

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Well, this is what makes me concerned about center tube integrity:

Respectfully, it does not take 25 years of engineering experience (which I don't have) to tell that if oil pressure can cause a collapse even where there is a full length tube (yes, this must have been an extreme case), it could blow right through an unsupported segment of element in even less extreme situations.

 

[kenw]

ok, i'll buy that. but unless it results in media bypass, which i would say is very rare based on your pics as an extreme example, i propose that's it is of no concern. I see a metal ring in the 1st pic. why is it collapsed and how is it different from a center tube that supposedly prevents collapse?

just looking for real data.