JD Closed Center Pumps Questions

Please educate me on the John Deere hydraulic pumps.
I m referencing the pumps below

AR94660 50 CM3
AR94661 65 CM3

I know that that the 60 CM3 is a larger pump.
How much fluid does the 65 pump compared to the 50?
What does CM3 stand for?

In know that the 63 CM3 pump has a larger inlet and outlet, but when I do a where used it shows the same O-Ring part number for the fittings on either pumps. This tells me that the fitting is the same size

Is there any negative effect by installing larger pump?

Thanks
 

''CM3'' means ''cubic centimeters of oil pumped/displaced per shaft revolution.

The outlet port sizes vary, one can replace the other by swapping out the fitting that connects the line to the pump.

There's no issue with going to the larger displacement pump, AFAIK.
 
Thanks, that makes sense now.

I am for sure that there is a correction factor that I do not have, but I think this is close enough.

So, this is what I come up with:

John Deere Hydraulic Pumps
AR94660 50 CM3
AR94661 65 CM3

CM3:
A cubic centimeter (cm3 or cc) is a measurement of volume. It is a derived unit of the International System of Units (SI). 1 cubic centimeter is equal to the volume of a cube with edges that measure 1 cm each. Since the volume of a cube is calculated as length width height, the volume of the cube is 1 cm3.

1 CM3 = 0.0002641721 gallon per minute per revolution


John Deere Pump P/N AR94660

50 CM3 = 0.0132086 gallons per minute per revolution
0.0132086 x 1400rpm = 18 gallons per minute
0.0132086 x 1900rpm = 25 gallons per minute
0.0132086 x 2500rpm = 33 gallons per minute



John Deere Pump P/N AR94661

65 CM3 = 0.01717118 gallons per minute per revolution
0.01717118 x 1400rpm = 24 gallons per minute
0.01717118 x 1900rpm = 32 gallons per minute
0.01717118 x 2500rpm = 42 gallons per minute
 
The pumps used to be called the 4 cubic.inches and the 5 cubic.inches in older parts book.

It is much easier to do your calculus in metric....

50cm3 at 1000 rpm = 50000 cm3 or 50Liters per min at 1000 rom.


Now do the same thing, how many gallons at 1000 rpm for the 4 cu.in pump ?
 
3 cubic inches = 49.16119 CM3
4 cubic inches = 65.54826 CM3

4 Cubic Inches = 0.01731602 gallons per minute per revolution

0.01731602 x 1000 = 17
0.01731602 x 1400 = 24
0.01731602 x 1900 = 33
0.01731602 x 2500 = 43
 
Not sure what your intentions / requirements are with going to a larger pump but make sure that you factor in a loss of efficiency.

I don't know what efficiency a JD radial pump in good condition produces at 1800 - 2000 psi but it won't be 100%....
 
(quoted from post at 12:42:10 01/27/23) Not sure what your intentions / requirements are with going to a larger pump but make sure that you factor in a loss of efficiency.

I don't know what efficiency a JD radial pump in good condition produces at 1800 - 2000 psi but it won't be 100%....

Since the pump destrokes when hydraulics are not being used and only displaces enough oil to maintain pressure when hydraulics ARE being used I doubt there'd be much of an efficiency difference vs. installing a larger gear pump in on open center system.

''Back in the day'' the ''larger'' pumps were used on tractors with hydraulic front wheel assist.

Driving such a tractor with the HFWA disengaged would be the same as installing the ''larger'' pump on a non-HFWA tractor.
 
(quoted from post at 10:31:13 01/27/23) 3 cubic inches = 49.16119 CM3
4 cubic inches = 65.54826 CM3

4 Cubic Inches = 0.01731602 gallons per minute per revolution

0.01731602 x 1000 = 17
0.01731602 x 1400 = 24
0.01731602 x 1900 = 33l
0.01731602 x 2500 = 43

Sounds so easy! :lol:
 

Some of the industrial applications installed a charge pump on the inlet side of the closed center system's radial pump. Reduced cavitation and improved GPM at high demand.
 
(quoted from post at 13:05:02 01/27/23)
(quoted from post at 12:42:10 01/27/23) Not sure what your intentions / requirements are with going to a larger pump but make sure that you factor in a loss of efficiency.

I don't know what efficiency a JD radial pump in good condition produces at 1800 - 2000 psi but it won't be 100%....

Since the pump destrokes when hydraulics are not being used and only displaces enough oil to maintain pressure when hydraulics ARE being used I doubt there'd be much of an efficiency difference vs. installing a larger gear pump in on open center system.

''Back in the day'' the ''larger'' pumps were used on tractors with hydraulic front wheel assist.

Driving such a tractor with the HFWA disengaged would be the same as installing the ''larger'' pump on a non-HFWA tractor.

The bigger pump will be nice at low rpm, to get your liader to.move faster. At full rpm, you will have to put bigger hydraulic pipes to cut pressure losses if you were to use max output. The smaller pipes are not going to hurt the pump, bucause you have a constant pressure system.

I had a 500C backhoe whith the 3020 engine, and the big pump, and you better moved the throttle some before lifting the loader. The flow difference was very noticeable.

Aldo, doing loader work and turning while lifting, turning might use more of 2cu.in of the pump, leaving only 2 cu.in for lifting. So going to 5cu will make the loader 1.5 faster.
 

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