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Oil pressure surge at 2k?

hunter7389

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Hi all, 2021 GT PP1 6 speed. 9k miles. Castrol Edge 5W30 and a fram ultra filter.

At steady state cruise right at 2K RPM, the gauge bounces back and forth around the 60psi mark, probably 5psi above and below. All other rpms to include idle it is perfectly steady. No funny noises, about 1K miles on this oil.

I have the digital dash, so (in fords wisdom) I don't get a digital PSI readout. Silly that my 2020 with the analog dash let me scroll to an oil psi readout, but not on the digital one.

Neither my 2020 GT PP1 or 2015 GT did this strange oil pressure needle bounce. Any ideas? I have a new oil filter ill put on tomorrow, just because.
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hunter7389

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New filter installed, several hour road trip completed. Still pulses at 2k. Not at 1950, not at 2050, only exactly at 2k. Super strange. Runs and indicates perfectly otherwise.
 

sk47

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Hello; This may be wrong but is a WAG (guess). Most oil pumps have a spring which limits the high pressure which can be made. If the spring is stout enough to keep oil pressure at a top range it will not open until the pressure builds to those pounds per square inch. Once the pressure builds to the set point the spring will stay open enough to keep the set pressure throughout the engine and bleed off the excess pressure.
An oil pump is mechanical and can keep increasing pressure as RPM's increase. I guess the increase in pressure would keep building unless some sort of pressure release spring limits the increase. So, my guess is at 2000 RPM the oil pump is building enough pressure to just start to lift the spring. Then as soon as the spring lifts pressure bleeds off and you see a fluctuation on the gauge. Go just a few RPM's above 2000 and the pump is building more than enough pressure to keep the spring partly open constantly.

Back in the late 1980's I did some mods to a 1963 Oldsmobile engine. The oil pump was located on the outside of the engine block. I replaced the stock pump with a high-volume pump. Essentially the pump chamber and the pump lobes were maybe a 1/4 inch longer. The larger pump lobes moved more oil at each rotation. In the kit were three different color-coded springs. The springs were rated at different coil pressures/compression strengths. I could use a stock spring rate or add stouter springs to up the pressure at which the bypass valve opened. I used the stock springs in that engine as I was more interested in greater volume than greater pressure.

I recently watched an episode of ENGINE MASTERS on Motor Trend TV. I think it is Season 6 episode 14. "It's the oil pump off". That episode went over how the pumps work. They were interested mainly if oil pumps affected HP, but the data made me feel better about my decision to use stock rated springs back a few decades ago.
 

sk47

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Hello; My other WAG is about oil level. If oil gets whipped and mixed with air that can affect oil pressure. I rejected this for the most part because it does not happen at other RPM's.
Did you (OP) come up with anything else?
 

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Google coyote gen 3 oil pressure.
There is a solenoid on the filter mount that regulates oil pressure.
Normal......
 
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hunter7389

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Hello; This may be wrong but is a WAG (guess). Most oil pumps have a spring which limits the high pressure which can be made. If the spring is stout enough to keep oil pressure at a top range it will not open until the pressure builds to those pounds per square inch. Once the pressure builds to the set point the spring will stay open enough to keep the set pressure throughout the engine and bleed off the excess pressure.
An oil pump is mechanical and can keep increasing pressure as RPM's increase. I guess the increase in pressure would keep building unless some sort of pressure release spring limits the increase. So, my guess is at 2000 RPM the oil pump is building enough pressure to just start to lift the spring. Then as soon as the spring lifts pressure bleeds off and you see a fluctuation on the gauge. Go just a few RPM's above 2000 and the pump is building more than enough pressure to keep the spring partly open constantly.

Back in the late 1980's I did some mods to a 1963 Oldsmobile engine. The oil pump was located on the outside of the engine block. I replaced the stock pump with a high-volume pump. Essentially the pump chamber and the pump lobes were maybe a 1/4 inch longer. The larger pump lobes moved more oil at each rotation. In the kit were three different color-coded springs. The springs were rated at different coil pressures/compression strengths. I could use a stock spring rate or add stouter springs to up the pressure at which the bypass valve opened. I used the stock springs in that engine as I was more interested in greater volume than greater pressure.

I recently watched an episode of ENGINE MASTERS on Motor Trend TV. I think it is Season 6 episode 14. "It's the oil pump off". That episode went over how the pumps work. They were interested mainly if oil pumps affected HP, but the data made me feel better about my decision to use stock rated springs back a few decades ago.
I'm familiar with that style, as I have a '72 Buick 455 that I built for my '69 Skylark. Its a complete giggle machine, just laughs and laughs...but yea, the pump is built in to the front timing cover, took a bit of sanding on a flat glass and shimming, then changing the spring to get the PSI I wanted.
 
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hunter7389

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Google coyote gen 3 oil pressure.
There is a solenoid on the filter mount that regulates oil pressure.
Normal......
I've been watching it closely, it is at such a specific RPM/PSI that this is the only thing I can think of.
 

sk47

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Hello; There is a by pass at or near the filter on most engines is my understanding. That is to open oil flow to the engine in the event the oil filter gets too plugged up to flow. The bypassed oil is unfiltered in this case but even so the engine has to have the oil.

I may be wrong about some sort of mechanism built into the oil pump itself. I am old school in the sense of being use to mechanical things such as springs. I do not as yet follow how a solenoid works to regulate oil pressure. A possible concern is solenoids require electric power and maybe even some computer instructions. An oil fashioned spring seems simpler and maybe more reliable.

Always something new to learn.
 

sk47

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Everything You Need To Know About Oiling Your Coyote V8 (fordmuscle.com)

Hello; Did some searching and may have found some information. Several articles about the oiling system but so far found only one with a reference to the springs in the oil pump. As i suspected the crank mounted pumps do use a spring to regulate pressure. I the link above is a picture of oil pumps showing the springs.

The good news according to the stuff I read is the stock oil pumps are very good from the factory.

I get this does not answer the OP's question to a good degree.
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