OEM Cummins Rebuild Help

jkidd_39

jkidd_39

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Jan 23, 2010
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I am swapping to 12v rods in my 05 CR engine.

I have a set of OEM Cummins main bearings on the shelf. I was wondering if they would work for me.

Part numbers: 3978818 and 3978820

Thanks guys.
 
ComnRailPwr said:
Them part# aren't ringing any bells but you need 12v rod bearings #3939859
Click to expand...

I think thats the part # scheid uses. The cummins rod bearing pn is 3969562 and i believe the upper and lower rod bearings are the same on the 12v rods. Just make sure you get cr mains and 12v rods.

The main bearing pn is 4955352
 
Well I think I got std commonrail main bearings. Here is a better pic.
b8063b23-3c54-1526.jpg
 
Google says those mains are to a qsb. Not sure what the difference. I just ordered mains and rod bearings for my build...accidently ordered cr rod bearings. Luckily the cr uses the 12v for the bottom of the rod and a differemt one for the top so i only had to replace 6 halvesty
 
sorry for my lack of knowledge but what is a qsb engine? a 05 CR is an ISB correct?
 
yea qsb is marine, isb is the one in our trucks. maybe the bearings are compatable, maybe not. give mumau or someone a call. good luck
 
No problem, just sharing a few things ive learned. Just double check with some of the more experienced guys on here too
 
The difference in the main bearings is only on the thrust.
What is the part # on your thrust brg.??
 
From the books at work:

12v Rod bearings: 3901170
5.9 common rail mains, upper: 3929016 / lower: 3929021
5.9cr thrust: 3927772 / 3945528
 
jkidd_39 said:
I am swapping to 12v rods in my 05 CR engine.

I have a set of OEM Cummins main bearings on the shelf. I was wondering if they would work for me.

Part numbers: 3978818 and 3978820

Thanks guys.
Click to expand...

Those part #s aren't in the books here, but they come up as ISB5.9 STD mains U/L on Quickserve.
 
You guys are posting so many differenet #s.. So what are the correct ones? You can use 12v rod bearings on the whole rod (upper and lower) when putting them in my 04 right? Then use the CR main bearings? Correct?
 
Just use 12v rod bearings, upper and lower. No need to change the mains, it's still your CR crank.
 
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