Bypass in engine and filter

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Would it be detrimental to performance if I put an oil filter with a bypass valve on as my engine which has a bypass valve built into the engine as well?
 
Whichever valve opens at lower pressure differential setting would open sooner. Other valve would only open if the first didn't do the job.
 
Assuming you've chosen a filter (and therefore bypass valve setting) which is recommended by a given filter manufacturer for your ride, most likely two bypass valves would simply be redundant, with no significant drawbacks. Same thing with anti-drainback valves for that matter. No real drawbacks in having an ADBV when it's not really needed. I'd guess that, like the Ford Taurus V-8 SHOs (to name just one make and model), a number of rides have come from the factory with both block and filter bypass valves.

[ November 10, 2004, 06:18 PM: Message edited by: TC ]
 
I've got something to add to this topic, Hopefully someone can explain this to me....
I have a Nissan truck, 1989 with a 2.4L engine.
(Original Fram equivalent for this truck was the ph43) I use the MC Fl-300 filter which has a bypass in the filter because there is no bypass in the filter mount. Over the years I have used other brands of filters but they were all comparable both in having a bypass and in physical size.
The filter that current books show for use in this truck is the Fram ph3682 equivalent- which is a smaller filter that does NOT have a bypass.....
I understand that sometimes smaller filters may be used for several vehicles so they may be considered a "generic/universal" size...but in this case they have now done away with the bypass functionality....someone who doesn't know about that may be using them and now they do not have an oil filter bypass on their truck....
I called the local Nissan dealer and he said they still show the older, larger filter that I am using the equivalent.

Just for reference here,
MC Fl-300 (purolator clone) -> 293 sq in of media
AC PF20 -> 243 sq in of media
Penske Maxpro CM43 (Wix clone) -> 263 sq in of media
These 3 filters have the bypass located at the inlet side of the filter (NOT at the far end like the FRAM version does...)

Anybody can explain this to me why the aftermarket folks think this vehicle no longer needs a bypass?? It hasn't grown one in the block anytime since I bought it in 1989...
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Putting a no bypass filter on a no bypass engine is one of the few serious problems in using non recommended filters. If the books are recommending it, there are going to be problems. No book was ever printed without an error. I would do some more checking before using one.
 
That's my point, I know better than to use them, I am using MC Fl-300 filters. But the general public that just looks at the book on the oil filter shelf may NOT know better...I'll probably call the Fram folks and just ask why they made the change..
 
The two bypass valves are for different purposes.

The filter bypass opens if the media is clogged, creating a pressure differential in the filter. Very thick cold oil might do same.

The engine bypass is to limit overall oil pressure. This can overextend the hydraulic lifters and stress seals.
 
Geoff

In this case we're talking about either two or three "reliefs". The oil pump always has its own internal relief. GMs ..many at least, tend to not use filter bypass valves and rely on a internal block mounted bypass for the filter. The oil pump is the only limiting factor for peak oil pressure ..the bypass(es) is/are the only limiting factor for filtration.
 
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