Shimmed my oil pump.. went from 35psi to 45-46 psi..

[Hammerhead]

(10-10-2016 )Rock hound trucking Wrote:  good day guys new user just reading some posts and learning shimming your oil pump with dimes ???? is there a video on this and what is the purpose u gain a few psi at a idel
just curious thx

There is a theory that part of the reason for all the cam issues with ISX's is due to Cummins reactionary fear of high oil pressure.
Back in the early Big Cam engine days Cummins used to be in the 50psi range (the first truck I drove was a BC, it ran at 52, then the BCIII I drove next ran 38). The machining processes then were not as good and consistent as they are these day. Because of this, Cummins went through a period of spun main bearings. Their failure analasys was that the oil pressure forced oil under the bearing surface, between the block and the bearing, while the crank was under high torque. To combat the rash of failures and mountainous warrantee claims, they went low pressure, high volume instead.
With the advent of the ISX, the cams were relocated into the head instead of the block. The oil pump is driven by the front crank gear, so naturally it is located at the very bottom of the block. This means that the last component to receive pressurized oil is the cam(s) and valve train. As the pressurized oil travels through the oil rifles and galleys, it loses a small amount of pressure each time a new rifle or galley passage is encountered. Because the cam(s), valves, and rockers are the end of the pressurized system, they receive the lowest pressure of oil. Particularly on the 540/870/871 which uses the second overhead cam to drive/pressurize the injectors. That results in very high stress pressures. The higher the stress pressures, the more oil pressure required to properly lubricate and create that oil barrier between components to reduce as much wear as possible.
Therefore, I and many others here want to see more than 35 psi operating temp oil pressures.
This is just pure conjecture on my part: but I wouldn't be surprised if you put a fitting into one of the overhead plugs and ran a gauge off of it if you only saw 20psi at operating temp and RPM's up there
IMHO the ideal pressure range is between 42-46 at 210-200* correlating operating temp. That will still be over 40psi at hard pulling 220*+ for my heavy haul application.