oil filter bypass check valve

[topradman]

Does anyone on here happen to know if the oil filter bypass check valve is located in the oil filter or in the oil filter housing? I do not trust any AI searches as I always get very mixed answers on mechanical stuff. The Ford parts dealer is not helpful (button pusher). I am trying to narrow down the possible contributors to low oil pressure at hot idle. the engine is newly rebuilt. all crank, rod & cam journals have been plasti-guaged and are right in the middle of tolerance sweep. cam phasers and all timing components including VVT's are new (of course), new melling oil pump based on jasper recommendations, new oil pump pickup, maybe 1 hr run time and runs good. Starts out at 65psi then when warmed up to operating, goes down to 19 psi and that is in mild weather, hood still not back on and no ac on (so not August in traffic, ac on, hood on & much hotter under the hood, which would probably lower the pressure more). this is with a new manual snap-on pressure gauge at oil pressure sensor location. engine is a 2005 version 5.4l triton w/3 valve heads. ( has Melling oil pump #10341 "high volume/high pressure")
Help?

 

[BC1]

There is a bypass in the filter. It does not regulate the engine oil pressure, The oil pressure maximum relief valve is in the oil pump. The low oil pressure at hot idle is probably scored up aluminum cam journals. Put some 10w-40..15w-50 in there. That will buy some miles until that 3V eats all its timing components again.

Edit. There are new rocker arms with tiny holes that restrict flow and help with maintaining higher pressure.

 

[topradman]

So again, the engine is freshly rebuilt including cylinder heads. ALL journals, were plasti-gauged, rods, mains, all journals on both camshafts and all were well within specs... phasers, oil pump upgrade to Melling, VVT's, complete timing set, all new cam followers & hydraulic lash adjusters... so I assume then that the "bypass" in the filter is actually a drain back check valve? What you're saying is there is a pump check valve that will regulate for too high of pressure. I understand that as well. what i am really trying to find is somewhere in this build where I might have pressure bleeding off as it warms up (or maybe it's doing it all the time?) but only concerning when it gets to operating temp. After warm up, if i add rpm, the pressure still moves up, it's the hot idle with the summer coming on that has me concerned and why I'm trying to check for anything that could be contributing to the low idle pressure. I think it should maintain above 25 psi at hot idle, especially when it it running high zinc content break in oil right now at 5w30 and once I change that back to 5w20 synthetic, I imagine hot idle pressure will go lower. (esp in elevated summer temps). I have quite an investment in this build and don't want to lose it. It has a Roush super charger and just a nice truck with a new engine. (this Roush is a baby compared to what my Z28 has in it).
(ps ... not an amateur, just not a tried and true Triton guy. Owned a few, this is the first build on one of these for me though).

 

[BC1]

The bypass in the filter is to keep oil flowing if the filter clogs or can not flow enough through the media on a cold start.

Did you look at the journals personally? Were there any grooves or scratches?

The answer to your low pressure is thicker oil period. Run that 5w20 and you will be back in there soon.

 

[RooflessVW]

Most engines have an oil pump bypass spring to keep the oil pressure under a set limit.

Most oil filters have a bypass valve to prevent too much pressure delta across the filter media, and an anti-drainback valve to prevent the filter from emptying from gravity or siphoning.

Sometimes these are built into the filter housing.

 

[RooflessVW]

Low idle pressure could be caused by:

Bad oil pump
Stuck open oil pump bypass
Too much clearance in the journals
Oil viscosity too low
Partially blocked oil pickup

 

[topradman]

The bypass in the filter is to keep oil flowing if the filter clogs or can not flow enough through the media on a cold start.

Did you look at the journals personally? Were there any grooves or scratches?

The answer to your low pressure is thicker oil period. Run that 5w20 and you will be back in there soon.

I did look at the journals personally as well as had my tech display to me all the plasti-gauge results.

 

[Donald]

I have seen odd things with oil pressure I could not explain by an oil filter but when I changed the filter the issue went away.

Given an oil filter is under $10 I would change it

But as others have said, the bypass in an oil filter is crude and mainly to allow oil to flow if the filter is clogged or it's super cold out and oil is really thick.

 

[zhaarnak02]

The answer to your low pressure is thicker oil period. Run that 5w20 and you will be back in there soon.

THAT is so VERY true. (unless you are located in Fairbanks, Alaska, during winter, at -60. Been there, done that, aint EVER doing it AGAIN.......