Boosting hydraulic pressure

[y112]

I have a 620 John Deere with a Bush Hog 3pt hitch log splitter. The splitter works generally well until I get into some big oak. Then the hydraulic squeals on the tractor and I have to knock the wood off the splitter wedge. I've been told the cylinder is big enough but the pressure relief valve on the tractor is releasing. Has anyone ever shimmed up the pressure relief valve on a '58-59 620 John Deere? I have a repair manual but was hoping someone had done it before.

 

[TractorTech]

No doubt the pressure is too low for the log splitter at 1200 psi, but increasing the pressure of the tractor will shorten the life of the pump or cause irreparable damage. I would be inclined to attach a PTO pump and reservoir for the splitter. The splitter valve most likely has a relief in the 2000-2500 psi range that will protect the system and deliver the results you desire.

 

[WranglerX]

IF you tractor hydraulic pressure is only 1200 PSI and splitter cylinder id is 4 inches you are only getting about 7.5 ton ram pressure...(you only care about push pressure)...

Even increasing pressure to 2000 PSI will only give you about 12.5 ton....

Most stand alone splitters with only 6.5 hp motors can develop 22 tons... I do primarily oak wood and my 22 ton splitter has to strain on some.... Would not consider anything less in tonnage (22 ton) unless it is really softwoods....

Hydraulic Cylinder Calculator

...

 

[y112]

No doubt the pressure is too low for the log splitter at 1200 psi, but increasing the pressure of the tractor will shorten the life of the pump or cause irreparable damage. I would be inclined to attach a PTO pump and reservoir for the splitter. The splitter valve most likely has a relief in the 2000-2500 psi range that will protect the system and deliver the results you d

 

[y112]

Appreciate your reply. The JD service manual shows how to add shims to increase pressure. I've never had it apart and it's externally accessible. I see you have Ford tractors and was hoping to get a reply from someone that has worked on these JD tractors. The old knowledge base is getting thin. Your PTO idea is interesting, but would the pto pump, near idle, make enough pressure to run the splitter? That 2 cylinder can idle at 500 rpm

 

[y112]

IF you tractor hydraulic pressure is only 1200 PSI and splitter cylinder id is 4 inches you are only getting about 7.5 ton ram pressure...(you only care about push pressure)...

Even increasing pressure to 2000 PSI will only give you about 12.5 ton....

Most stand alone splitters with only 6.5 hp motors can develop 22 tons... I do primarily oak wood and my 22 ton splitter has to strain on some.... Would not consider anything less in tonnage (22 ton) unless it is really softwoods....

Hydraulic Cylinder Calculator

View attachment 4080647...

 

[y112]

I'll check the JD manual to determine the pressure. If it turns out to be less than the splitter, I might have to mount a gas engine and separate pump. I do have a Kawasaki "650D twin" engine off my mower that should work. What size pump should i get to run the splitter?. I get stuff from Northern Equipment

 

[Seven Gables]

Safest way to increase the force without harming the old low pressure system in that Deere is to mount a larger diameter cylinder to the splitter. Just going from a 4”to 5” diameter cylinder would increase the force from ~15000lbs to about ~23500lbs which is over a 50% increase. Only drawback is it would slow the cyl stroke time by about 50% also, if that matters to you.

 

[WranglerX]

If you are thinking of pumps....

2 Stage (Log Splitter) Pumps | Hydraulic Pumps | Hydraulics | www.surpluscenter.com

2 Stage (Log Splitter) Pumps,Hydraulic Pumps,Hydraulics, 8 GPM 2 STAGE HYD PUMP Brand new, two stage HI/LO pressure hydraulic gear pump. Ideal for

www.surpluscenter.com

Keep in mind you may only need 5-10 HP for low volume pups....

Also reservoir and filter assembly....

 

[TractorTech]

Appreciate your reply. The JD service manual shows how to add shims to increase pressure. I've never had it apart and it's externally accessible. I see you have Ford tractors and was hoping to get a reply from someone that has worked on these JD tractors. The old knowledge base is getting thin. Your PTO idea is interesting, but would the pto pump, near idle, make enough pressure to run the splitter? That 2 cylinder can idle at 500 rpm

My knowledge is old and broad, not just Fords. I may not know the old JDs inside and out, but the hydraulic system in those are basic gear pumps.

One thing no one has mentioned, whenever you adjust pumps, you need to have a pressure guage to determine what pressure the relief is opening.

Your pressure may be low anyway being it is an old tractor, but it wasn't made to operate at the higher pressures that today's hydraulics ooerate.

Midifiying your splitter by adding an engine would be the best