Back in the spin on game...questions

[CR94]

Originally Posted By: ZeeOSix
The center tube doesn't need to be attached to the end caps for structural integrity - it's purpose is to prevent the media from imploding from delta-p. ... There are plenty of cartridge and even spin on filters (ie, Denso) where the center tube just slips into the center hole.
Yes, as I recall pointing out a few months ago when goodtimes's complaint first appeared.

Toyota (Denso) cartridges for my car at least place the inside folds of the pleats close enough to the center tube of the cap that the tube can support the media against inward collapse. I used a Purolator Classic which had much more radial space between the media and the center tube. Therefore, the Purolator media hypothetically would've had to collapse badly before contacting the center tube, so the center tube effectively does nothing. Fortunately, in reality it didn't collapse---or even tear.

Corresponding Fram cartridges of all levels seem to be intermediate in that regard.

 

[goodtimes]

Originally Posted By: ZeeOSix
The center tube doesn't need to be attached to the end caps for structural integrity - it's purpose is to prevent the media from imploding from delta-p (Engineering 101). Media doesn't implode on eCores with windows 1/2" wide. There are plenty of cartridge and even spin on filters (ie, Denso) where the center tube just slips into the center hole.


The center tube serves more than one purpose in most filters. I have only seen one canister filter without center tube used as structural support, an IAP. The media is very strong on those.
The Denso center tube, totally contrary to what you said, is the structural element separating the adbv and the leaf spring. On one end the tube fits into the adbv and on the other end it presses on the leaf spring. When the filter is clamped together it is all about the center tube keeping the media from collapsing. What you said about the 1/4" gap is exactly what I said it was. With a gap, the assembly pressure is on the media. After the media deforms it stays that way it isn't a spring. Then what we have is a "rattler."
Take apart a Denso and look at it with common sense, no engineering needed to see how it works. The media is only sealed in the gasketing, it is being held only. Ask for Fram engineering drawings and I am sure you will not find a 1/4" gap where the center tube ends.

 

[ZeeOSix]

Originally Posted By: goodtimes
Ask for Fram engineering drawings and I am sure you will not find a 1/4" gap where the center tube ends.


I never said it's designed to have a 1/4" gap per drawing. I said even with a 1/4" gap (extreme example) nothing is going to fail because it's not that critical to make the center tube a 100% "structural" member when the media element can take what compressive force the leaf spring gives - especially if the media is up tight against the center tube. Even if it does compress a littk bit, it's not going to loosen the guts. The center tube's main job is to prevent the media from imploding from delta-p.

How many "rattlers" have we seen here? A hand full at best, and they weren't from the center tubes being 1/8" or less too short.

 

[DuckRyder]

I don’t think that is a gap you are seeing in the picture. I will go look later though. I recall all of these being quite good. We used to see center tube alignment issues with the old Honeywells but they seem lots better lately. (incidentally though it is hard to read those elements have “TG”, “A02” and “EG” written on them by me.)

I agree the center tube provides support for the media against the leaf spring. One being drastically short or drastically out of alignment would be an issue.

Where minor misalignment is concerned I believe the leaf spring and ADBV is designed to account for that possibility.

Motorking has said that the media used in the A02 has a lower efficiency See: Honda OEM filters I don’t believe he can get into it further than that understandably.

Some part numbers of FRAM racing filters are available under $10.00 on Amazon (and perhaps other places)

Apologies for derailing this OP.

 

[DuckRyder]

It is a small gap. I will add a picture to the other thread later and continue discussion in that thread.