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That stock gauge is way off. On a cold 0-10F day, you don't see the stock gauge at 100psi, do you... I was seeing 90psi on a warmer day and that was even running amsoil synthetic, so conventional would be in the 100's when it was cold.

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I can hit 100+ . This is how. 50* outside,warm up for 5 min, 1500rpm in first gear. I shimmed my pressure spring about .060.

--- Update to the previous post...

Just curious what everyone is seeing for oil pressure. I'm seeing 60-70 idle cold engine, 25-40 idle warm engine and 50-60 cruising down the highway.

mostly same as me except your cold temp.
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"A gerotor style oil pump draws oil from the crankcase through the suction tube and delivers it through the block where it enters the oil cooler cover and pressure regulator valve. When oil pressure exceeds 65 PSI, the valve opens exposing the dump port, which routs excess oil back to the oil sump."(page 9-929) So you shouldn't see more than the 65 PSI even on a cold morning start.

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The 3rd gen's may be slightly different, as I know the cold oil releif valve is set at 75.. ButWarm idle 20-22, 50 psi at 1500 rpms, cruise 55-63 depending on coolant/oil temp. Long hard grades can drop oil psi from 57 to 50. Cold idle varies up to 30-40, and I have never seen over 85 psi. I do measure oil psi on the drivers side of the block above the ECM thou, I think it's a more accurate indication of pressure in the block.I also run 2-3 psi higher now that I have a BB turbo that uses less oil than a journal bearing.

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"A gerotor style oil pump draws oil from the crankcase through the suction tube and delivers it through the block where it enters the oil cooler cover and pressure regulator valve. When oil pressure exceeds 65 PSI, the valve opens exposing the dump port, which routs excess oil back to the oil sump."(page 9-929) So you shouldn't see more than the 65 PSI even on a cold morning start.

I'd like to hear more on this. I was under the impression that the only bypass was the oil filter one so even though it would likely bypass the oil filter when cold, it would still be at over 100psi throughout the rest of the engine. I would think the oil wouldn't flow through the engine if it was too thick to flow at 65psi and therefore your engine would be starved of oil until the friction of the oil that was in there warmed it up enough to flow at that pressure. But I admit I am not the lube system expert which is why I want to know more on this :thumb1:
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I'd like to hear more on this. I was under the impression that the only bypass was the oil filter one so even though it would likely bypass the oil filter when cold, it would still be at over 100psi throughout the rest of the engine. I would think the oil wouldn't flow through the engine if it was too thick to flow at 65psi and therefore your engine would be starved of oil until the friction of the oil that was in there warmed it up enough to flow at that pressure. But I admit I am not the lube system expert which is why I want to know more on this :thumb1:

The cold oil relief and oil filter bypass valves are separate valves, thou they can both operate at the same time. The cold oil relief valve limits the max pressure of the system, this keeps seals from blowing out from excessive pressure caused by a cold motor/oil. 2nd gens are set at 65 psig and 3rd gens are set at 75 psig. The filter bypass valve keeps oil flowing to the motor in the event of a plugged filter. Very cold oil can also cause this to open by creating the 50 psid due to poor flow properties.
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So far we haven't listed any info from a 12V motor, just 98.5+ motors, the 12V may have a higher cold oil relief valve, or yours isn't working properly. They can't divert all the oil back to the sump so seeing pressure above the set point isn't uncommon, I can see about 10 psi above mine with very cold oil.

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I just looked up the specs from Cummins... This is from a 3rd gen and a 4th gen..[TABLE=class: box][TR][TD]Oil-regulating valve-opening pressure range[/TD][TD]448 kPa [65 psi] to 517 kPa [75 psi][/TD] [/TR] [TR] [TD]Oil filter differential pressure to open bypass[/TD][TD]345 kPa [50 psi][/TD][/TR][/TABLE]This is from a 2nd gen. Regulated Pressure414 kPa [60 psi]Anyone have a serial number from a 1st get?

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ther is a tap beneath the ecm on my 02. i tapped into it when i put my booster pump on years ago. it would not allow the pump to come on before it registered oil pressure. i believe it was another way of keeping to much pressure during starting. did not know that then but it makes sense now that i have learned more abotu the system. can you tap that for an oil pressure gauge?

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So if I was to hook up a oil pressure gauge where is a good place? Above the filter? And if I disconect the the oil sender a tap in there will it set of cel light? How many psi gauge do I need 100 psi?

I like the port above the ECM, and yes a 0-100 psi gauge.

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--- Update to the previous post...

Alright I found ISX's ESN... It says this.

Regulating Valve Opening Pressure 449 kPa [65 psi]

The specs were the same for a 1992 Engine.

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