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Rawze · 09-10-2019, **(Subject: Oil Pump Shimming )**

(09-10-2019 )Mattman Wrote: Does Cummins feel that more oil pressure is not needed? They could build a pump to supply whatever oil pressure they wanted.

Me personally I like oil pressure.

*(what I have been told, is only here as speculation )...
On some of the older model engines (pre-ISX), they had a problem with them spinning bearings as they got older. high oil pressure would sometimes get behind the shells and make them want to spin. - The red maker lowered the pressure on all their engines to help stop it. - Not sure if the ISX has ever seen that problem, but some phone calls to them in the past has revealed that the ISX oil circuits are designed for withstanding 80-psi max, though I would not want to run one more than about 48-50 psi due to seeing rear structure gasket getting leaky much beyone that on an older engine.

I know at about 45 psi+, the oil pressure and flow in the top end is significantly better. I would suspect that the pistons run cooler as well due to increased flow.

Of those who have been doing this mod now for years, no one has reported so far that they they have seen any negative effects from it that I know of outside of a person or 2 installing shimms incorrectly.

Mine has been done since my inframe, but also it has run a gallon of gear lube its whole life (all 1.3 million miles essentially) as well. No problems yet. It runs about 48 psi when cold and about 45 or so when hot.

just my own thoughts/exposure to it any ways.

BTW: Detroit still has this problem of spinning bearings as they get older, especially the DD15's but this only typically happens if you change the oil filters, oil, and fuel filters all at the same time. It happens due to dry-starts. Detroit recommends to never change the fuel filter until after you change the oil and oil filters, crank the engine up and let it build oil pressure again,.. then shut it down and replace the fuel filter separately to prevent this. - there have been many law-suits over this by detroit customers and oil change places over the years.