Log splitter not building pressure

[ctf58]

24x4 cylinder
16gpm pump 2 stage
160cc honda engine
Energy valve with detent
Haldex pump
Hi guys,
Bought this old splitter and it is not building much pressure . New cylinder and engine. I put a pressure guage on the inlet at the top of the cylinder and only get 500psi when running the ram all the way to the plate at the bottom of the splitter and the engine will stall after about 5 seconds. Same results in a peice of 10"oak. I moved the guage to the inlet of the hand valve, on the line from the pump and got the same reading. It acts as if it is not going into stage 2, BUT, when I retracted the ram the guage will spike to 2000psi if I hold the handle and not allow the detent to disengage the valve. I'm at a loss.. could the valve be mounted in reverse and if so can the handle and detent swap ends?
Thanks in advance.

 

[triptester]

The 160 cc engine is too small for a 16 GPM 2-stage pump

 

[ctf58]

Thank for the reply triptester,

That is what I was thinking, but my father-in-law has a splitter with the same cylinder and motor and I literally had them side by side. If mine couldn't split it I would throw it on his and it would barely increase rpm's and split it with ease. I do not know what size pump is on his but the cycle times are nearly identical so I figured they were close in gpm's.

If the motor is undersized, which I agree it is, why is it able to build pressure up to 2000psi in reverse?

 

[ctf58]

Ok guys, at the recommendation of a person at a hydraulic supply house I changed the valve. He thought since I'm building 2000psi when I retract the ram but only 500-750psi when trying to split that the valve might be bypassing going forward. He was not trying to sell me parts because he told me to go to the local farm supply store to purchase cheaper than he had.
I put it on and cycled it numerous times to try to bleed air out.
Same dang results 500-750psi extending ram regardless if motor is stalling or running fine. 2000psi retracting ram. And now it is spitting fluid out the vent cap at me after it retracts and I let pressure build. It just keeps spitting oil until I push forward..

I'm at a loss and no one around here "works" on log splitters that I can find.

Suggestions please.

 

[dave ensign]

Reverse the lines from the valve to the cylinder. See what you get.

 

[rancher2]

Ok guys, at the recommendation of a person at a hydraulic supply house I changed the valve. He thought since I'm building 2000psi when I retract the ram but only 500-750psi when trying to split that the valve might be bypassing going forward. He was not trying to sell me parts because he told me to go to the local farm supply store to purchase cheaper than he had.
I put it on and cycled it numerous times to try to bleed air out.
Same dang results 500-750psi extending ram regardless if motor is stalling or running fine. 2000psi retracting ram. And now it is spitting fluid out the vent cap at me after it retracts and I let pressure build. It just keeps spitting oil until I push forward..

I'm at a loss and no one around here "works" on log splitters that I can find.

Suggestions please.

Sounds like the seals on the piston inside the cylinder are blown letting the oil bypass the piston when the cylinder extends.

 

[muddstopper]

Not going to speculate a lot since I cant see the pump or valve. I will say if the pump will build 2000psi while retracting, it should build 2000lbs while extending, but only if it is meeting resistance. what does the pressure guage say when you extend and dead head the cyl all the way out. The fact that it doesnt kill the engine at 2000psi when dead headed fully retracted and does kill the engine when fully extended is telling me the pump is build more than the stated 500psi. I can suspect that while extending at 500psi, it is only meeting minimal resistance. Even is the seals inside the cyl are blown it would still have to build enough pressure to kill the engine and wouldnt be able to do that until the cyl was fully extended, and really shouldnt even then, any oil that bypasses the cyl on extend should return to tank thru the retract hose port. My guess is that the piston seals are bad as Rancher2 suggests, allowing oil to bypass, but not bad enough to not allow the pump to build full system pressure. I suspect the pressure builds to stall pressure faster than the operator can observe.

 

[ctf58]

Thanks guys, I've been trying for 2 days to upload. I cannot seem to get videos to load here so hopefully these links will work. Deadhead forward and deadhead reverse.

 

[muddstopper]

Have you tried reversing the hoses to the cyl

 

[pdqdl]

Sounds like the seals on the piston inside the cylinder are blown letting the oil bypass the piston when the cylinder extends.

Yes, except that he stated it was a new cylinder.

I'm guessing that some of the valve plumbing is done wrong. Hydraulic valves can act very strangely if you don't have 'em hooked up right, with all the bypasses and plugs hooked up right.

Is your valve designed or set up for "power beyond"?
Where does the return line flow to?
Is there a system check valve?
Does the valve have two return line ports, or does it bypass internally?
Was it designed for a normally open hydraulic system, or normally closed? (This would really leave you guessing if normally closed, too!)

The best way to test if your valve is working right is to take it off and put low air pressure (I just blow through them), and see where the air goes when the valve is in each position. Then back out the pressure relief, and see if the air goes through that port when the outflow to each valve position is plugged (as if the cylinder is stalled)

A decent way to test is to leave your pump high pressure line hooked up to the inflow side of the valve and actuate it then, manually testing for where the air goes as the valve is actuated. DO avoid the dangerous notion of testing the cylinder with air pressure. It is likely to fly to the end of the travel (open or closed) and do some very serious damage.

Another consideration is for the unusual circumstance that you have some pilot operated check valves on the cylinder that are malfunctioning. These little options are great safeties for an aerial device hydraulic cylinder, but can really screw up your operation if they quit working. It would be very unusual to have that on a conventional cylinder.

 

[pdqdl]

If the pickup line is connected high on the tank, you will run out of fluid as the cylinder uses fluid out of the tank. The return line can be mounted high, but the oil pickup line must be low on the tank. Many systems use a larger diameter low pressure line for the return line.

I've seen top-mounted pickup lines that had an internal pipe for a lower pickup point inside the tank. Those pickup pipes can rust out or break off inside the tank, leaving you a situation where the full volume of the tank isn't useable. This too, could be your problem.

Another note: you should NOT be able to stall the engine out. Loaded hard, the pressure relief should be adjusted to allow high pressure oil bypass so that the engine can keep running.

 

[user 74409]

Per Honda website, Honda GCV160 engine is rated at:

Net Power Output*

4.4 HP (3.3 kW) @ 3600 rpm

Most 16 gallon per minute 2-stage pumps for sale today require minimum of 8 hp.

 

[pdqdl]

.... And now it is spitting fluid out the vent cap at me after it retracts and I let pressure build. It just keeps spitting oil until I push forward..

The vent at the top of the tank?

If that is solid oil coming out the top, you've probably got an air leak somewhere in your system that is possibly filling the system with air while the tank is overfilling with oil. This could be from anywhere on the suction side of the pump, and possibly the pump itself around the input shaft seals.

If your tank was filled to the top and the cylinder was extended, that might cause a similar problem, but I would expect that to happen as soon as the cylinder was retracted, and not after it had built pressure.

If you have foamy air coming out the vent, that is an even stronger suggestion of a vacuum leak, although I would expect you to notice the cavitation sounds in the pump under any vacuum leak condition.

 

[Del_]

I wonder if the 2 stage pump is switching over at 600 psi, which is usually the factory standard.

It may have been adjusted up in pressure, which would not be a good thing with an undersized engine. With an undersized engine less than 600 psi may work out better.

 

[pdqdl]

Per Honda website, Honda GCV160 engine is rated at:

Net Power Output*

4.4 HP (3.3 kW) @ 3600 rpm

Most 16 gallon per minute 2-stage pumps for sale today require minimum of 8 hp.

Yeah, that's kinda puny for a log splitter.

That being said, a normal hydraulic cylinder draws more pressure under no load when retracting. The surface area of the piston is greater on extension, so the pump has less resistance against the somewhat constant friction of moving the ram in and out.

I don't think horsepower is related to the observed problem, but certainly might be an issue otherwise.

 

[pdqdl]

I wonder if the 2 stage pump is switching over at 600 psi, which is usually the factory standard.

It may have been adjust up in pressure which would not be a good thing with an undersized engine. With an undersized engine less than 600 psi may work out better.

That's a good thought, but not a factor (I don't think), as explained in my previous post.

I have also considered an odd condition where each flow direction has it's own separate bypass valve and pressure setting. That could screw things up if they are set wrong, but I can't imagine finding such a valve on a log splitter, especially a cheapo that has been replaced once.

I think he has the tank pickup hoses reversed, and is picking up from the high side. Lacking experience, he might not know the difference (by listening) between too much pressure and cavitation caused by no fluid coming into the pump. That would also pump air into the cylinder and cause the retraction fluid level to be too high. Until the extending cylinder used up the excess oil again.

I kinda think he would have to have a rather small hydraulic reservoir to see such bizarre observations.

 

[dave ensign]

Think it is just a bad valve that is bypassing on the power stroke.

 

[Oletrapper]

The 160 cc engine is too small for a 16 GPM 2-stage pump

I have to respectfully disagree. A 160cc Honda can be either a 4.7hp or 5hp which is plenty enough to work a factory built log splitter. Honda rates the 160cc at 4.4hp; 4.7hp; 5hp but I don't believe that. Under rating is often done to get around EPA regulations in certain states. In my opinion the key is the two stage pump. When the 2nd stage kicks in, it is only pumping 3 to 4 gpm if that. However, a 160cc will never run a single stage pump at 16 gpm. Not many of those out there anymore.
I believe your problem will be in the pump. Not kicking down to second stage. As you said, you bought it and it is old. No telling what was done to it before you bought it. Regardless, let us know what turns out to be the problem. OT

 

[CJ1]

Oh good grief, just plug both lines at the cylinder. Pressure both ways, fix the cylinder. Same problem, it's the valve. It could have a valve with a bad cyl port relief, if it is not a splitter valve. We quite working on splitters because of what some people cobble up for hydraulics! Cj

 

[Oletrapper]

Oh good grief, just plug both lines at the cylinder. Pressure both ways, fix the cylinder. Same problem, it's the valve. It could have a valve with a bad cyl port relief, if it is not a splitter valve. We quite working on splitters because of what some people cobble up for hydraulics! Cj

Op said he changed the valve, same problem. Said has new cylinder. Putting my money on the 2 stage pump. jmho OT