Help please, Log splitter won't split

[VW Splitter]

It only has enough pressure to split small straight grain wood. When it pushes against any thing large or a small knot the ram just stops. The 8HP Briggs & Stratton keeps on running, it only bogs down slightly. It has new 13.5 GPM 2 stage pump from Northern Tool. I have not dealt with a 2 stage pump before, I can't tell that it switches gears. It goes from moving quickly to a stand still. Actually, if you hold the valve in the forward position long enough, it might finely split the piece, but only if it is a easily split piece of wood. If everything was working properly, shouldn't the engine bog down and die when I hit something too mean to split? Is the hydraulic fluid bypassing somewhere? Thru the Valve? The cylinder? That would explain why it doesn't build pressure, and the engine doesn't bog down and die.
A little history.... I found this home made splitter in a guys back yard, (should have left it there) with weeds and trees growing up thru it. It looked like it had a lot of potential, so I thought I should rescue it. It had a 6HP B&S engine with a 6 to 1 gear reduction on it. So it was slowly spinning a ??GPM pump that was made to turn at a low RMP. It has a 4" cylinder with a 42" stroke. It had a 60 second cycle time. I didn't have enough patients or time to use it with that kind of speed. I bought a good used 8HP B&S engine, a new 13.5 GPM pump, flushed out the old hydraulic fluid, Installed a filter and a tank vent, replaced the low pressure hoses, and got it going. The cylinder and the valve are original equipment. The cylinder leaks just a little when you use it.
I am open for suggestions and words of wisdom, lay it on me.

 

[Sleepy]

I saw one doing exactly as you describe, owner had put a new pump on it also.
On it, the seals on the piston were leaking internally. After a cylinder rebuild, it worked like new.

 

[muddstopper]

I see it has a gauge mounted, does it work and what kind of pressure does it read. I cant tell from the pic if the control valve has a adjustable relief, probably hid by the gauge and hoses. The first thing I would try is to extend the cyl all the way out to max extension. I would then remove the hose from the rod end of the cyl and plug it, but leave the cyl port open. Then try to extend the cyl past full extension and see if any oil sprays out of the open cyl port. If it does, then the cyl piston seals are shot. If it doesnt spray any oil replace the hose, then try to screw in the relief valve to see it will allow it to build more pressure. If that doesnt work, I would suspect the relief valve is bad, broke spring or piece of trash holding it open. You should be able to remove the relief and tear it down to check for a broken spring or piece of trash, If the relief valve looks good, clean it up and reassemble and try adjusting the pressure again. If that doesnt do it, then you probably have pump problems.. The hyd tank doesnt look really big, is it full of fluid. With the cyl fully extended, check the oil level in the tank and make sure it isnt being sucked dry.

 

[VW Splitter]

I see it has a gauge mounted, does it work and what kind of pressure does it read. I cant tell from the pic if the control valve has a adjustable relief, probably hid by the gauge and hoses. The first thing I would try is to extend the cyl all the way out to max extension. I would then remove the hose from the rod end of the cyl and plug it, but leave the cyl port open. Then try to extend the cyl past full extension and see if any oil sprays out of the open cyl port. If it does, then the cyl piston seals are shot. If it doesnt spray any oil replace the hose, then try to screw in the relief valve to see it will allow it to build more pressure. If that doesnt work, I would suspect the relief valve is bad, broke spring or piece of trash holding it open. You should be able to remove the relief and tear it down to check for a broken spring or piece of trash, If the relief valve looks good, clean it up and reassemble and try adjusting the pressure again. If that doesnt do it, then you probably have pump problems.. The hyd tank doesnt look really big, is it full of fluid. With the cyl fully extended, check the oil level in the tank and make sure it isnt being sucked dry.

Muddstopper, Thanks for the game plan to figure this out. I did what you said , extended the cylinder out, unhook the rod end hose, capped the hose , then tried to extend the cylinder more. The open cylinder port had a lot of flow coming out. I'm gonna need to rebuild the cylinder. Problem is the cylinder is pretty much welded in place. The rod end is welded to the push plate, and the push plate doesn't come off the beam. The cylinder does unbolt from the butt end. But I don't think there is enough slack in it to back the outside part of the cylinder back off the rod. Does the ring thread off the end of the cylinder, then the rod will just pull out? How hard is it to replace the seals, if I can get this thing apart?

 

[muddstopper]

Looks like the builder didnt plan on doing any future maintenace. I would suggest you take a grinder with a cut off wheel and try to cut the gussets off the end of the cyl and see if you can free it from the pusher plate. Hard to tell but if you get the rod free, then you can retract the cyl and just pull the base out. The cap on the cyl barrel should just screw off but you will need either a very big pipe wrench, or the proper spanner wrench. I suggest trying to free the rod cap before removing the cyl from the machine so that you have the cyl base mount to hold the barrel from turning. The cap might be, probably will be, pretty hard to break loose. You can take a propane torch and warm just the cap if it wants to be stubborn. I like to wrap the barrel close to the cap with a cold wet rag to prevent the barrel from heating up while heating the cap. Once you have removed the rod cap, you should be able to just pull the rod out of the cyl barrel. The piston will be held on with a big nut, which will probably be hard to get off also. If the nut is a nylon lock nut, you wont be able to heat it to get it loose as that would melt the nylon and ruin the nut. Last big nylon nut like that I bought was about $30-$40, so keep that in mind before you put heat to it. After removing the nut and piston, you should be able to slide the cap and rod glands off to replace the gland seals and the oil seal in the cap.

I will suggest an alternative. I believe you said the stroke was 42 inches. Do you need that much stroke? If not, I think I would buy myself a shorter cyl and redo the pusher plate and base mounts to fit the new cyl size. A shorter stroke would improve you cycle time a bunch.

 

[VW Splitter]

While in the shower tonight, I was just thinking about what all would be involved it fixing this cylinder as apposed to installing a new one. I do a lot of building/designing in the shower. You are correct, I don't need the 42' stroke. A little redesign and a new cylinder is a good option. Thanks for your input on this project.