Bypass location, does it matter?

[zoomzoom]

Read this and comment please!

This design does not meet Ford standards for three reasons. With dirt and metal chips collecting on the far end of the filter if the by pass valve is located down there it will be swept up when the bypass valve immediately above it opens. Oil coming from the engine washes over the dirty side of the filter media when the bottom by pass valve is open. A top bypass oil filter passes unfiltered oil to the engine but a bottom bypass filter washes dirt off the filter add it to the dirt load in the unfiltered oil and hits the bearings with a much greater amount of debris - at least in theory! The last strike against bottom bypass filters is the problem with ice. In theory, the dome end of the oil filter should be the lowest point of the lubrication system and it work as a place to collect excess moisture and water. If water was in the bottom of the filter and froze it could either obstruct or freeze the bypass valve closed. The PureOne by Purolator has a bottom bypass valve, but the Motorcraft, made my Purolator for Ford has a top bypass valve. I don't want to get in Dutch with either design camp and will try to get some balancing information from Purolator and Amsoil.

more on the topic:
http://www.shoclub.com/lubrication-oil/lubrication-oilpart2.htm

 

[jsharp]

All the advantages listed for a top bypass design make sense but only Ford is a stickler about requiring it. It's easy to avoid the issue by purchasing only filters that have the top bypass. I can't see any disadvantage to this...

 

[ZiTS]

I couldn't get that link you posted to work, but have you taken a look at the Motorcraft FL-2005 and its' equivalents? It has two by-pass valves in it. On the Motorcraft and others, the BPV is located at opposite ends of the filtering element. On the Wix/Napa filters, both of the BPV's are pretty much placed one-on-top-of-the-other, on the "top" end of the filter. I've always wondered if there is a benefit/drawback to either design.

-Z

 

[FowVay]

Often times, the location of the by-pass will be specified by the manufacturer because of the position that the filter is mounted on the engine. If a filter hangs upside down on a engine and the by-pass is mounted in the top of the filter then when it goes into by-pass (usually during cold starts) much of the carbon and particles that aren't imbedded into the filter media will be the first to be pushed through the by-pass valve. If the by-pass were mounted on the threaded end then there is a much greater reduction of heavy particles passing through unfiltered because they are sitting at the bottom of the filter. The same holds true for filters that are mounted in the opposite direction.

For the filters that are mounted sideways I don't know that it makes that much of a difference.

[ December 25, 2003, 09:16 AM: Message edited by: FowVay ]

 

[TC]

In agree with FowVay. I love the comment someone once made on a board, "Gravity is the best filter." Picture a conventional filter with bypass in the closed end, with the filter hanging down in a pendant position. Anything heavier than oil, including sludge, metal filings, water, etc., will settle down into the closed-end dome. Should the filter bypass -- and bypass actually happens quite often, even in a new filter -- that junk may get washed through the valve and into the engine.

The obvious question is "Are there any DISADVANTAGES to open-end bypass?" I'd suggest:

1. It requires more engineering since that end of the filter is packed with several components.
2. The tooling and manufacturing costs can be greater.
3. It requires a bit more space than closed-end bypass, therefore leaving less room for the media cartridge. Wix appears to make up for this by adding pleats, per the pleat count in filter surveys. (Closed-end bypass typically uses NO space in that the spring and poppet are located inside the cartridge.)
4. Following through on the above, even Wix -- which touts their open-end bypass -- builds some filters with closed-end valves, purportedly due to cost and/or production streamlining benefits.

Open-end bypass is better...but there's plenty of first-rate filters out there with closed-end valves. This shouldn't be the deciding factor for most people. If you suspect your engine might "soil" the filter dome with junk (one could think of several scenarios -- a very worn or dirty engine, a grocery-store-and-back engine in which water condensate is never driven out, a sludge monster, etc.), perhaps open-end would be more important.

[ December 25, 2003, 02:39 PM: Message edited by: TC ]

 

[Spector]

Real issue should be does it make any difference in the life of the engine, will you get 200,000 miles in lieu of 175,000? Will never know and 99% of the population will never keep a car long enough to care.

If you have enough particles of the size that can cause wear floating in the oil and are worried about whether they bypass and go back into the engine you have other problems that are more important then the location of the bypass valve.