Log Splitter Pressure

WildArkie · Apr 5, 2011

Well making a divit on the edge of the plug and hitting it using a punch and hammer several times did the trick. I started to think it was not going to do it but it finally gave way.

But, I did not find what I thought I would. There is not a pressure adjustment screw. Just a spring and steel ball pressed against the inlet side. I guess a new log splitter valve is needed.

Now, since my cylinder is 6 inches doesn't that require a different valve compared to smaller cylinders. I thought I saw that somewhere.

J_J · Apr 6, 2011

The control valve should be able to handle the volume from the pump.

The PDF you showed had an adjusting screw. Apparently what you have is an older valve with a non adjustable relief.

glastron23 · Apr 6, 2011

the plug ,spring and steel ball are your PR, to adjust it you turn the plug in to increase the pressure and turn it out to decrease it. the plug pushes on the spring that pushes on to the steel ball. the more spring tension applied on to the ball the more hydraulic pressure needed to move the ball off its seat to release oil back to the tank side of the valve. the balls seat is just a hole between the in port and the tank port.
as far as the valve being to small this is not a problem in your case because of the pump size, at 4 to 5 GMP and a 6 inch cylinder you will have a slow machine. at 6 inches you require at least 16 GMP to increase the speed to a good workable speed. Jim

WildArkie · Apr 6, 2011

Then I am still at a loss for what is causing the cylinder to abruptly stop at 800 psi and the engine to bog. The plug seems to be bottomed out after taking it out and putting it back in a few times. It is flush with the valve body so is it ok to be recessed in the port to increase the pressure? The spring was really stiff so that may be why I think it is bottomed out.

J_J · Apr 6, 2011

Your pump is putting out 8.14 at 2500 psi when ran at 3600 rpm. At 1800 rpm, it is putting out 4.1 GPM. At the upper limits you are running out of HP with the 9 HP engine.

Do you know for sure if that hyd gage is any good? Is there any way for you to test the gage, or get another one?

Does the log splitter split any wood.

You can test the pump by putting a relief valve across the pump, set at 2000 psi, and run the hose off the relief valve to the reservoir, After the relief valve, add the needle valve and the output hose to the reservoir, and and open the needle valve all the way. Start the engine, , and run no faster than 1800. Slowly turn the needle valve in and watch the gage. A full test will occur when the needle valve is closed all the way, and the fluid now has to go through the relief valve. What you are doing, is providing resistance to the fluid, and if it is a good pump, it should relieve at 2000 psi.

Your engine can not support 2500 psi, and 8.14 GPM.

If the gage is bad, then it is understandable that the engine will bog down as you stated.

Your engine will bog down trying to pump more than 5.5 GPM, at 2500 psi.

Your pump is not matched to the pumps rated capacity.

J_J · Apr 6, 2011

6 in cyl
2 in rod
4.1 GPM

extend time, in per sec = .6

time to split a 24 in log, will take about 40 sec

push force is 70,686 lbs, or 35 ton

J_J · Apr 6, 2011

I found this .

Nice Energy Single Spool Hydraulic Wood Splitter Valve | eBay

Maybe you can use it. I believe I would get a regular log splitter valve that I posted with detent return. ..

WildArkie · Apr 6, 2011

Thanks for all your help JJ, and everybody else who has commented.

It does split wood as long as it is old and soft. I split several pieces of Sycamore but even a few of those did not split. When it would not split one the cylinder would press against the wood and the gauge would jump to 800 and the engine would bog down. The cylinder stops and will not try to press farther. I let off the valve handle and the gauge drops to zero and the engine comes back up. Same thing at full extend and retract. The gauge will go up to 200 or 400 on some pieces before they split but if it hits 800 it stops.

It has been a while but I think I timed the full extension at about 14 seconds and retract at about 8. I would really like a two stage pump but was trying to use this for a while first.

I know a hydraulic shop that may test the pump for me without charging so I will take it there in the next day or two. I don't have another PR or needle valve. I will see about another gauge.

Same on the valve. I was hoping to use this for awhile before buying another.

Stupid Question: How do you normally know/test the engine rpm? I can use a laser shaft sensor and reflective tape from work.

J_J · Apr 7, 2011

Tach,dwell meter for 4 cycle engine, Photo tach meter, manual touch rpm indicator. The engine sounds different for different rpm.

Small Engine Tachometer Hours Meter

Stewart Warner hand held tach

You touch the rubber shaft end to the rotating shaft, and the rpm is indicated on the meter.

J_J · Apr 7, 2011

Something is still not right here. If you have a 6 in bore cyl, and it has a 2 in shaft, and the engine is turning 1800 shaft rpm, the pump is putting out about 4.1 GPM. I compute 40 sec to extend, and you say about 14 sec.

Again, you don't have the HP to run that pump at 3600 rpm. At around 5.5 GPM's, and max resistance, the engine/pump starts slowing down and if you keep the resistance up, the engine will stall.

Have you tried running the engine at half speed? and if you run the cyl out to full extend, does the engine stall or does the relief activate?

Even at 1/2 engine speed, and if the pump can put out the pressure , the cyl has the capability to produce 35 ton's of force.

Engine/pump rpm's dictate the GPM's through the valve.

You need a 14 HP engine for that pump to develop full potential.

J_J · Apr 7, 2011

I have to correct some of my figures, as I was computing for a 24 in log.

With a 16 in cyl, it will take about 26.6 sec to fully extend the cyl.

WildArkie · Apr 7, 2011

The outside diameter of the cylinder is 6 inches and the outside diameter of the rod/shaft is 3.5 inches. The travel length is about 16 inches.

I will adjust and measure the rpm and test the pump.

shansen · Apr 8, 2011

The valve in the pictures is 1970's or earlier vintage. The relief was correctly identified. The valve is not cracked, the slot in the adjusting screw and valve body are very corroded. Also, the valve in the ebay link is a 3-postion, 4-way, spring centered valve, probably mid 80's vintage. Our C-908 valve is the log splitter valve we make. The plumbing and mounting connections will be very, very close to the valve in these pictures. I have not read this entire thread, but just wanted to point out a few things regarding our products. The C-908 available at our website: Hydraulic Cylinders
I would state the price here but I don't know if that is allowed.
Steve Hansen
Applications Engineer
Energy Manufacturing Co., Inc.
(319)-465-3537 X-402
(319)-465-5279 FAX
shansen@energymfg.com

Haywire · Apr 8, 2011

WildArkie said:
The outside diameter of the cylinder is 6 inches.

Figuring 1/4" wall thickness, it's probably a 5.5" cylinder.. That's a pretty big one. If you get this thing up to 3000psi, I expect you'll never run up against anything that it won't split.

Ian

WildArkie · Apr 11, 2011

Well to give an update I used a punch and hammer to turn the pressure relief screw in. After a full turn it loosened up and I am able to turn it with a screwdriver now. I turned the engine throttle down to lower the rpm's and the engine stalled at about 1500 psi.

I turned the throttle back up and played with the PR so the gauge will show 2000 to 2500 psi when it is fully extended or retracted. Problem is when it hits this pressure now it kills the engine. No bogging just stops it.

I am able to split the wood that I was not able to before. I split several pieces. But, when it did get a tough piece and the pressure went to around 2500 it killed it without warning (other than psi). I would start the engine again and either reposition the wood piece or try to push again. Sometimes it would split the second time and sometimes just kill the engine again.

So, is the pressure relief not working stopping the fluid to return to the tank and killing the engine or is the engine just weak and dying under pressure. It either boggs down or dies wherever the pressure relief valve is set at, 800 or 2500. One other thing, I turned the pressure down to about 500 psi and the engine still started to bogg down until I released the valve handle.

glastron23 · Apr 12, 2011

Wild... your engine is just running out of horse power to keep the pump turning,,,, when you stall the hydraulics you need about 2 hp per gallon of pump flow at 2500 psi. this is were the 2 stage pumps come in real handy, it allows lower HP engines to work with a high flow/low pressure(for fast extend/retract) and low flow/high pressure (for tough splitting) and keep the engine from stalling. Jim

J_J · Apr 12, 2011

If you say that your pump went to 2500 psi, and stalled, that is what is supposed to happen. At max engine rpm, you are pumping 8.14 GPM, and the pump, using cyl resistance, is trying to produce 2500 psi. It needs about 14 HP at that rpm and pressure, so now you have the answer.

The engine to support that pump should be about 14 HP. So at max rpm on your 9 HP engine, you are running out of HP. The system is just not matched.

You need another engine, and new valve.

WildArkie · Apr 12, 2011

That is not what I began this discussion wanting to hear. I was thinking I might have to get a two stage pump and maybe a valve as a added bonus to have the detent feature if I could not get everything lined out. Now it looks like I have to do the biggie, engine. This will take some time to look and find something without buying new. I guess that is what I get for getting the splitter free and expecting to it to be easy.

Since my single stage pump increases the gpm with higher rpms will the two stage pump limit the high pressure to 4 gpm at 3600 rpm allowing a lower HP engine? I should say I want to know if the higher rpms will make a two stage pump do 6 gpm, on the high pressure, creating the same HP shortage for me.

https://www.surpluscenter.com/item.asp?item=9-1390&catname=hydraulic

Haywire · Apr 12, 2011

You don't have to do the engine... it's either the engine, or a pump that the current engine will support... think of it as a see-saw. It needs to be balanced. You can take some off one side or add to the other.

Ian

Edit: this one requires at least 8hp, this one only requires 6hp if your engine is a little tired and both of them will over double your ram speed.

J_J · Apr 12, 2011

WildArkie said:
That is not what I began this discussion wanting to hear. I was thinking I might have to get a two stage pump and maybe a valve as a added bonus to have the detent feature if I could not get everything lined out. Now it looks like I have to do the biggie, engine. This will take some time to look and find something without buying new. I guess that is what I get for getting the splitter free and expecting to it to be easy.

Since my single stage pump increases the gpm with higher rpms will the two stage pump limit the high pressure to 4 gpm at 3600 rpm allowing a lower HP engine? I should say I want to know if the higher rpms will make a two stage pump do 6 gpm, on the high pressure, creating the same HP shortage for me.

https://www.surpluscenter.com/item.asp?item=9-1390&catname=hydraulic

If you like your engine, then this two stage pump will work.

https://www.surpluscenter.com/item.asp?item=9-1390&catname=hydraulic

How well do you like your valve?

There are limits as to what one can do, and sometimes things can be manipulated, but in general, rules are rules.

We are simply trying to keep you from making mistakes, and wasting money.