bypass buzz

[bchannell]

After looking at a bunch of oil filters cut open over the years, I fail to see any great advantage to where the bypass is located. I'm not an expert and would love to hear more about this, but it I know the can has to have a certain pressure to open the bypass. That initial pressure would cause contaminated oil to go back into the engine, with the flow route being them same, no matter where the bypass is located. The drop in pressure as the bypass opens would then cause the bypass to close and the cycle is repeated. I just don't see how the slightly shorter path, caused by the front location of the bypass valve, would make all that much difference. The pressure is still going to flush contaminate from the media?
How does the location, of the valve, affect contamination?

 

[bmwtechguy]

When the bypass valve is located in the dome end of the media, there is the possibility that the oil will wash past the dirty side of the media, picking up contaminants lodged there and send them through the bypass valve and into the engine. A better scenario is to have the bypass in the base so that any bypassed oil does not take up potentially damaging particles from the dirty side of the media. In actual use does this mean shorter or longer engine life? Like many other points obsessed on here at BITOG, I doubt it does.

 

[Dick in Falls Church]

The bypass valve operates on the difference between incoming and outgoing pressures. My physics classes are long past, but I would think there would be minimal if any oil coming back through the media. If the filter is so full of collected particles that the bypass is open all the time, it won't make any difference because you'd be running unfiltered oil. If the bypass is opening temporarily (such as during a cold start), I wouldn't think the oil could pick up much if any of the particles out of the filter media.

As bmwtechguy says---

 

[Gary Allan]

Quote:
I fail to see any great advantage to where the bypass is located.


Me too. Ford's engine division appears to be the only one that insists on this distinction in location, and they don't appear to have enough depth of conviction on the topic to prohibit the use of filters with dome end bypass valves. I've only ever seen reference to one member ever giving credence to the notion that it had any weight in reality. That is, the supporting evidence that it's much ado about nothing far outweighs the marginal evidence otherwise.

Loading a filter to the point of causing bypass use would be extreme in my opinion. I'm sure that it happens, but I would tend to think it rare. If you have a dirty engine(as in byproduct production design) and operate it in its dirtiest mode most of the time, you might load a filter enough to make loading a factor in bypass valve frequency of use ..but it's not its primary purpose; at least from when it's mostly put to use.

Read this: It's about as good as I can express it. #1061871 - 01/10/08 05:35 PM

In spite of no counters to my assertions, others continue to believe otherwise. I'm always open to opposing points of view ..but so far, there's been nothing to alter my perceptions of observed events in my filter bypass valve testing.

 

[bchannell]

I didn't mean that oil would come back thru the media. I meant that the rise and drop in pressure would tend to dislogde contaminates, by virtue of a flushing effect, and put them back into the outgoing oil stream, no matter where the bypass is located. It's an obsessive point, but isn't most of what we discuss?

 

[dnewton3]

My oppion is that the act of the bypass valve functioning (regardless of how rarely it actually occurs) is WAY more important than the location of said valve within the filter or mount.


BITOG OFFICIAL MISSION STATEMENT:

"... It's an obsessive point, but isn't most of what we discuss?"

 

[Gary Allan]

Quote:
I meant that the rise and drop in pressure would tend to dislogde contaminates, by virtue of a flushing effect, and put them back into the outgoing oil stream, no matter where the bypass is located.


But there is no "pulsing" involved. (hmmmm...how do I say this in my oddball descriptive manner without getting someone lost

)...


The pressure attenuates. It's not some undulating over critical undamped action. You're looking at it like a "spillway". Now the pump relief valve is a spillway for excess flow ..but not the bypass valve.

You don't have some massive "relief" action that sweeps some massive share of the flow through the bypass valve. The valve itself is matching the resistance that the media presents. (I'm very tired - I just watched over a homeless shelter for the past 10 hours during a code blue event)

You may be able to catch this view here (it requires several associative thought processes to make it work). Think about the Bay of Fundy.

 

[Brian Barnhart]

The advantages of front end bypass valve location have been discussed here many times before. Some choose to ignore the advantages, some dismiss the advantages because they aren’t convinced, while others like Ford and Jeep spend extra money to install well thought out front end bypass valves on millions of vehicles.

Frams and Supertechs are available for anyone who wants the cheapest possible filter. Their filters have dome end bypass valves made of plastic or pheonelic buttons and metal springs, or metal to metal clickers, or a front end bypass that relies on the properties of nitrile rubber to regulate bypass. They are fine for anyone who believes oil filters are of little benefit and those wanting the cheapest product available. Purolators are very similar. At most only a few of their entire line of bypass equipped automotive oil filters contain a front end bypass.

I used only dome end bypass filters on my Jeep for years without problems. Now, during the winter months, I use only front end bypass filters on the Jeep when sub zero temperatures make at least some bypassing likely.

 

[Dyoel182]

I've said it before but what puzzles me about the Ford bypass issue is that on the same engines in other brands, namely Mazda, they dont spec that same filter with the front bypass.

 

[Brian Barnhart]

Are you referring to the filter installed on the engine at the factory, or the aftermarket filter?

 

[Dyoel182]

I'm referring to both the original filter and to the filters listed in the manual for the parts counter.

 

[Brian Barnhart]

I’m not sure of the current practice, but the front end bypass factory filter on my 2002 Ranger had no name on it. I suspect the same filter would have been used on the B3000 as well. However, since Ford and Mazda each establish their own prices, dealers, and service and warranty practices, it’s not all that unusual that they may differ on oil filter recommendations. This is especially true in the area of service parts since Ford and Mazda have many platforms that they don’t share.