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Problem after oil pump shim fixed - Printable Version

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Problem after oil pump shim fixed - Brock - 02-14-2017

I shimmed my oil pump a while ago and it ran good for a bit then dropped off to below factory psi. I had shimmed mine about 3/4" which is higher then some would recommend but I'm a idiot and that's what idiots do.

My problem was the oil pressure bypass relief valve on the oil filter base. I believed I had updated it, I went to cummins and asked for the update. When I put it in, it looked the same but I thought maybe the spring was stronger or built from a different metal. After watching rawzes video on it I realized that nope, that was not the case. I tore a strip off Cummins but they showed me how it doesn't even show up as a option on Thier computer so how would they know.

Anyhow, put the new one in and now my psi is back at a magical number!

Anyone shimming their oil pump, be sure to update the bypass valve as well..... don't be a Brock, he's a moron!


RE: Problem after oil pump shim fixed - Texasdude74 - 02-14-2017

What's your hot, low idle and road speed pressures now?


RE: Problem after oil pump shim fixed - Brock - 02-14-2017

I haven't warmed it up all the way and drive it as I'm putting a pro ride on right now but before it acted up I believe I was around 30psi idle, 40psi 900rpm idle and I was cruising down the road between 50 and 60 somewhere, I believe it was closed to 50 when at full temp, 60 when the motor is cold.


RE: Problem after oil pump shim fixed - Starlight - 02-14-2017

(02-14-2017 )Brock Wrote:  I haven't warmed it up all the way and drive it as I'm putting a pro ride on right now but before it acted up I believe I was around 30psi idle, 40psi 900rpm idle and I was cruising down the road between 50 and 60 somewhere, I believe it was closed to 50 when at full temp, 60 when the motor is cold.

I'd say 50psi at full temp is the max you'd want to go as you don't want to "wash" out your bearings.


RE: Problem after oil pump shim fixed - gearhead - 02-15-2017

I have done alot of research on the washing out bearings i don't think it could be done without some major pressures. Cat runs 90 psi cold and about 60 to 75 at highway speed.


RE: Problem after oil pump shim fixed - Johnboy - 02-15-2017

Has anyone seen the long term benifits of shimming the pump yet? Just curious before I do mine.


RE: Problem after oil pump shim fixed - Magard - 02-15-2017

I haven't seen one of these pumps, just curious about what drives the pump. Seems like almost doubling the pressure could make that pump work a lot harder. Wouldn't want to create more problems. Major problems with a failed pump. I'm sure you guys are on it. But sometimes to much of a good thing can be bad. I've been contemplating this mod. Just hate to crack into a pan that's not leaking, cause when I get done with it there no telling. Could go either way.


RE: Problem after oil pump shim fixed - Rawze - 02-15-2017

pump handles it just fine. it is a gear pump with large gears for high volume.


RE: Problem after oil pump shim fixed - jimeneztrans84 - 02-15-2017

I have about 50k miles that I shimmed the pump with 8 dimes and nothing has happened yet. Runs 45 psi at operating temperature rolling 55-60 mph and 41-43 psi climbing steep hill. I did see more oil leaking on the external leaks I currently have because of more pressure from the oil pump.