Aux Spool Valve size

[bubbacuse77]

I bought the Prince Wolverine 2 spool valve Surplus Center - 2 SPOOL 8 GPM PRINCE MB21BB5C1 DA VALVE
My plan is to add this valve to the tractor as may have done before for 4th and 5th functions through the power beyond. I have a JD 3520 that is open center and until now didn't understand that the implement pump pushes fluid through every valve in series. JD specs the tractors implement pump at 8.6 GPM and Pince says the valve is nomimally 8 GPM. Is the valve to small and going to restrict flow trough the entire system or worse yet cause the implement pump to constantly labor resulting early failure? Anyone use this valve yet on JD 3020 series tractors?

Thanks for any insite

 

[J_J]

That valve should be OK, as very few cyl or motors will use the total GPM's that the pump is capable of pushing. If you lower the max engine rpm, you push less GPM's through the valve, and should be able to use that valve with no problems.

Engine rpm determines the GPM's the pump will pump.

If you are really concerned. This valve would also work, and also has float.

http://www.surpluscenter.com/item.asp?item=9-7693&catname=hydraulic

 

[MtnViewRanch]

Do you ever use your tractor at full throttle? If you do, then I would think about getting a bigger valve. You will have that 8.6 GPM getting pumped through an 8GPM valve and the fluid will get heated up just from that. If you don't and never will, then you might be fine with what you have. I would check into returning that valve and getting the bigger one myself.

Good luck.

 

[Mechanos]

Depends on your tractor... does it have a separate pump for implements and power steering? For example, my 955 has an implement pump rated at ~7 GPM. However, my tractor uses the same pump for everything (expect the hydro drive unit). The first device after the pump is a flow divider that splits 30% of the flow off and routes that through the power steering and then onto the PTO clutch. The remaining 70% of the flow is routed through the SCV's, PB, and finally to the rockshaft cyl. So, even at full output of the pump, the hydraulic implement circuit only sees ~5 GPM.

 

[J_J]

Depends on your tractor... does it have a separate pump for implements and power steering? For example, my 955 has an implement pump rated at ~7 GPM. However, my tractor uses the same pump for everything (expect the hydro drive unit). The first device after the pump is a flow divider that splits 30% of the flow off and routes that through the power steering and then onto the PTO clutch. The remaining 70% of the flow is routed through the SCV's, PB, and finally to the rockshaft cyl. So, even at full output of the pump, the hydraulic implement circuit only sees ~5 GPM.

This is what he has.

Hydraulics

Type Open Center

Pump Rated Output, gpm (L/min.) 13.9 (52.5)

Steering 5.3 (20)

Implement 8.6 (32.5)

Pump Type Dual gear

Maximum Operating Pressure (PSI) 2500

Draft Control Type Position control

Remote Control Valves Available 5

 

[IceStationZebra]

First, all valve ratings of X gpm is at some vendor determined pressure drop. They push more and more oil from port to port until they get to the pressure drop they want. The flow vs. pressure drop curve is usually not smooth because of turbulence from the sharp edges. Vendors sometimes play games by using a higher pressure drop so they can rate their valves at a higher flow. To really answer your question you would need to know if the rating is P-to-A/B or P-to-T. P-to-T could well flow better since it is "straight through" the valve.

Second, the 8.6 gpm figure is probably on the high side. Wear and hot oil will cause that number to go down.

If you go from 8.0 gpm to ~8.4 gpm the pressure drop will only go up about 5% at full flow/WOT, nothing major but you will be creating a little more heat.

ISZ