bypass valve - why did they do this?

[metroplex]

I bought 4 super-tech filters today and noticed something odd:

I bought two ST2s - direct replacements for Motorcraft FL-820-S (4.6/5.4 ford modular motors)

One of the ST2s has a bypass valve on the base plate of the filter (where it threads onto the oil filter adapter) ala FL-820-S while the other ST2 did not.

I noticed that the valve takes up almost 1/4 of the entire filter, reducing the filter media size.

I bought two ST16s (direct replacements for FL-300s or the smaller 5.0 oil filters designed for limited block clearance) and none had the bypass valve.

I have Wix equivalents at home and the two FL-300 replacements did not have the base plate valves.

The wix equivalents for the FL-820-S also did not, but they did have this weird "H" metal thing welded to the bottom (has a hole in the middle).

I've been using the filters w/o the valves on the base plate for over 2 years now and never noticed anything really different. Any ideas?

BTW I have an FL-1A and even tho the filter is huge, the valve on the base plate takes up a great deal of space reducing the filter media size. Unless of course there's media behind the valve but it can't filter anything cause there are no pass-holes?

 

[Alex D]

metroplex.....I noticed the same thing when I bought an ST8A which is the SuperTech replacementfor the FL-1A filter. The bypass filters are CRITICAL on ford oiling systems because a Ford 302 or other small block will not live with lowered or restricted oil flow that would not arm a Chevy. Fords only have one oil galley.....I took it back to Walmart and got an FL-1A.

quote:

---

Originally posted by metroplex:
I bought 4 super-tech filters today and noticed something odd:

I bought two ST2s - direct replacements for Motorcraft FL-820-S (4.6/5.4 ford modular motors)

One of the ST2s has a bypass valve on the base plate of the filter (where it threads onto the oil filter adapter) ala FL-820-S while the other ST2 did not.

I noticed that the valve takes up almost 1/4 of the entire filter, reducing the filter media size.

I bought two ST16s (direct replacements for FL-300s or the smaller 5.0 oil filters designed for limited block clearance) and none had the bypass valve.

I have Wix equivalents at home and the two FL-300 replacements did not have the base plate valves.

The wix equivalents for the FL-820-S also did not, but they did have this weird "H" metal thing welded to the bottom (has a hole in the middle).

I've been using the filters w/o the valves on the base plate for over 2 years now and never noticed anything really different. Any ideas?

BTW I have an FL-1A and even tho the filter is huge, the valve on the base plate takes up a great deal of space reducing the filter media size. Unless of course there's media behind the valve but it can't filter anything cause there are no pass-holes?

---

 

[metroplex]

I'm using synthetic engine oil so it should fly up to the valvetrain area.

For some odd reason - the Penske/Wix filters for my 5.0/302 (the smaller filter) both have the bypass valves ala FL-1A. The ST16/ST8A (i have one of the 8As also) both do not have the bypass valves.

one of the ST2's (For the Ford OHC 4.6L V8) does have the valve while the other ST2 doesn't. None of the Penske/Wix Modular engine oil filters have the valve.

Is it more important to have the valve for the OHV 302 V8 than the OHC 4.6/5.4 modular engines?

 

[metroplex]

SSMOKN enlightened me on this situation:

newer ST2 filters do NOT have the valve at the base plate - they use the bottom part for the valving.

Apparently the spring-loaded mechanism that's mounted at the base performs the same function as the bottom valve, just different designs.

The spring loaded one like the Motorcrafts and Amsoils take up quite a bit of room.
The ST8A filter is smaller than the FL-1A, but if you account for the space displaced by the valve in the FL-1A, the ST8A has more usable filter media.

 

[Pablo]

This has been discussed several times here. I believe it to be a mandated Ford spec thing AND I believe it is a good idea. Mainly because: when the bypass opens it doesn't flush collected crud into the system. I still have the torn apart SDF-42 in the garage (basically a shorter version of the SDF-15 - FL-1A) - And I can say although it does take up some percentage of space in the smaller filters - the OD of the by-pass mechanism is smaller than than the ID of the inner filter tube, so it doesn't interfere too much with oil flow. If this mechanism does impede flow then I say it's a faulty design......

Earlier discussion on said by-pass valve

[ December 30, 2002, 08:54 PM: Message edited by: Pablo ]

 

[metroplex]

Its not oil flow that I'm concerned about - its the usable filter media.

The FL-1A is substantially larger than the ST8A (both are designed for the same engine). The FL-1A is about 1/4" longer than the ST8A but the bypass valve also takes up about 1/4" of the media.

The ST8A, OTOH, has usable filter media almost from the anti-drain back valve down to the lower bypass valve.

 

[Pablo]

The media is still used - that's my point. Yes the device is down inside the center tube, but there is still the filter media around it. If anything a filter designer could make these types of filters have even more filter media by using the full length where the older designs had the bypass.

 

[metroplex]

How can the media be used if there are no holes for the oil to pass thru?

The base-plate spring bypass takes up a bunch of space and there are no holes next to it - I felt it with my finger. THe usable media only comes after the mechanism.

The ST8A (doesn't have the base-plate valve) has usable filter media almost right after the anti-drain back valve down to the lower bypass valve.

 

[Al]

The oil will travel through the media and then down between the inside of the pletes toward the bottom and then go through the holes lower down toward the end of the filter. (I believe)