3 Point Log Splitter Valve Question

CAH2873 · Sep 7, 2021

Hello- I have a 17 year old 3 Point Log Splitter that I purchased from Tractor Supply and it is in need of a new Valve. I contacted Energy and they cross referenced the part number to their C908 valve. They said it is a direct replacement for the existing one. It is rated for 2,500 P.S.I. I run this splitter on a Kubota M6800 and and Kubota M5-111. My question is: Do I need to put a regulator into the inlet side of the valve to keep it under 2,500 P.S.I.? I typically let the tractor run at 1,200 - 1,300 RPM's while splitting.
I have used this splitter a lot and it has started leaking in the past couple of years. I have rebuilt it a couple of times but it is time for a new one.

Thanks In Advance,

CAH2873

WranglerX · Sep 7, 2021

The replacement valve will operate under any pressure from tractor (within preset relief pressure in tractor system) .... The bypass setting (2500psi) of valve actually only controls max pressure in a non regulated pump system or a system which has a higher loop pressure (tractor system or at pump regulation) than the control valve relief valve pressure ....... It's the pressure to ram and ram cylinder diameter that determines "tonnage" of splitter....Raising relief valve bypass pressure in control valve, tonnage of splitter goes up, lower bypass pressure of relief valve and tonnage goes down.... IF valve is open loop system, and control valve not operated, essentially there is no pressure in splitter system (only what total tractor system allows) , only when valve is operated does it build pressure in splitter because it is working against a resistance (volume of ram cylinder), once pressure in ram reaches the "set limit" of relief valve pressure "in system" should not go beyond the preset pressure...

For instance:
A 4 inch diameter cylinder operating with relief valve set at 2500 will give about 15 tons at ram...
A 4 inch diameter cylinder operating at 2000psi will give about 12 tons at ram...
A 4 inch diameter cylinder operating at 3000psi will give about 18 tons at ram...

Hydraulic Cylinder Calculator

The real question here is what is max pressure allowed in you tractor system before it's internal bypass operates?..... IT may be lower than the 2500PSI bypass of the control valve...

Cursory search seem to indicate your M6800 has a system pressure regulated to 2300-2350 PSI so what ever control valve setting is at (2500psi) is probably a none issue and not even come into play......

CAH2873 · Sep 8, 2021

That helps me out. Thanks for the help!

WranglerX · Sep 8, 2021

Revisit of pressure relief valve setting...

In simplified diagram below the function of pressure relief valve in control valve is to insure the pressure never increases in the area outlined in red goes beyond what the PSI setting of pressure relief valve in control valve is....