This discussion started under another topic but deserves it's own thread due to it's importance:
Hmmmm, Has anybody else done this swap and has any info to add. This is a new one to me. :idea:
The pumps will interchange. You can even use one of the aftermarket super high volume 6bt pumps, but you don't really need it on a 4bt. But, If you are using a compound turbo setup, it would help. Those turbos take a large volume of oil!
Wrong 6bt has a wider gerotor. Pumps are NOT interchangeable
The larger gearotor is one of the reasons the 6cyl oil pump will pump more volume. The second reason is that the driven gear on the gearotor is smaller on the 6 cly pump, so the pump has a taller gear ratio, and spins faster. The gearotor is internal, and the external dimension of the pumps are identical. Also, the 4 cyl and 6 cyl blocks are machined identically in the oil pump area. The 6cyl pump is a cheap and worthwile upgrade. I agree, you shouldn't install a 4 cyl pump in a 6 cyl. I know the Cummins manual says they are not interchangable, and that is probably so you won't install a 4 cyl pump in the 6. My 4bt has a 6 cyl pump and it works just fine!