Is bypass in threaded end really best?

[TallPaul]

I got to thinking that with the mounting stud extending into the filter it may actually extend past the bypass valve and make for a convoluted flow around the valve and into the hollow outlet stud. On the other hand, bypass in the other end of the filter can may be somewhat convoluted too, but at least that pressurizes the inflow part of the can, whereas the bypass in the threaded end may result in less pressurization of the outside of the can and perhaps with the flow around the threaded stud some backflow the wrong way throught the filter media? If so, this could dislodge material into the oil. I am kinda thinking this bypass location thing may be a 6 of one, half dozen the other type thing.

 

[Roger]

I presume you are referring to the Ford designed bypass valve. One of the reasons Ford uses this arrangement I understand is that many of their filters mount at a 45 degree angle. Ford reasons that at this angle, dirt and moisture could settle on the botton and be more prone to washing back into the engine if the bypass valve were on the bottom side of the filter.

 

[TallPaul]

The dirt makes sense, but the moisture I think would get through anyway. I still wonder about the flow around the mounting stud, which I will have to measure, but from memory seems long enough to would extend past the bypass valve.

 

[T-Keith]

I thought the reason for the Bypass valve at the threaded end was so the oil wouldn't flow across the dirty end of the filter picking up particles on the way.

-T

 

[TallPaul]

That's what I understood, but still, if the hollow outflow stud extends past the bypass valve there is going to be a turbulence generated by the 180 degree flow reversal that potentially could cause higher pressure inside the filter element to push crud backward out of the element.

 

[edwardh1]

As big as the japanese are in engine durability, if it made any difference they would all do it one way or the other.

What do the japanese do with OE filters?

 

[n8wvi]

Subaru dealer replacement filters (made by Purolator) have the bypass valve in the 'bottom' end, not the threaded end. The filters that come on them from the factory (Toko Riki IIRC) have the same design. Off the shelf Purolator filters for these same engines have the same design. I agree, if Subaru thought it was important to have it at the threaded end, they would have done that. Too much of Subarus reputation relies on engine longevity, even the general avaiation guys trust these engines!

Dave

 

[RavenTai]

quote:

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Originally posted by TallPaul:
That's what I understood, but still, if the hollow outflow stud extends past the bypass valve there is going to be a turbulence generated by the 180 degree flow reversal that potentially could cause higher pressure inside the filter element to push crud backward out of the element.

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I would not worry about it there is a good bit of room arround the filter mounting stud for the oil to flow, a 180* turn is not a big deal for oil it had a good ammounf of pressure pushing it and it makes manny convoluted twits and turns through drilled and cast passages on its long path from pan to bearing

let us know what measuremetns you find