log splitter help

[Oldtimer]

Hopefully in the next week I will be at home to check this out. So far yes I either have a flow restriction or a pump stuck in low. I there a way to adjust the pump? I was told that it is possible to adjust the pressure of it like form 600-1000 on th high side and if that is out the pump may only stay in the low flow side as the high flow has pressure set too high. Anyway Thanks for the ideas

The pump has a (USUALLY HAS) 3/4" sized cap over a flat-head screw adjustment.

Turn it clockwise to increase the pressure required to "offload" to the second stage. So, you'd want to turn it "out" or counter-clockwise to make it hit second stage "faster".

If I read your post correctly, you suspect it's adjusted so that it shifts to the second (slower) stage with very little load...so turn the adjustment "In" all the way, then back it off 1 full turn, then test. If it's no faster, then it's not the adjustment. At that point, I'd set it "midway" until it was fixed and you can re-adjust under a heavy load.

 

[mlh29]

The pump has a (USUALLY HAS) 3/4" sized cap over a flat-head screw adjustment.

Turn it clockwise to increase the pressure required to "offload" to the second stage. So, you'd want to turn it "out" or counter-clockwise to make it hit second stage "faster".

If I read your post correctly, you suspect it's adjusted so that it shifts to the second (slower) stage with very little load...so turn the adjustment "In" all the way, then back it off 1 full turn, then test. If it's no faster, then it's not the adjustment. At that point, I'd set it "midway" until it was fixed and you can re-adjust under a heavy load.

Ok, I am home finally. Yesterday I went through a few things. I pulled the suction strainer, eliminated it, replaced return filter and all fluid. still same speed. I checked all the 1/2 inch lines going to cylinder. They are clear. I unhooked the return 3/4 line and seem like I have alot more flow through it than either of the 1/2 lines to cylinder. The 1/2 inch lines coming from valve to cylinder just seem to flow 1/2 of the amount of the 3/4 return line. I also checked the 1/2 supply line from pump to valve, seems I can pump about 5 gallons in 40 seconds or so. Adjusted pump setting screw in and out, same results, still slow, probably 20-25 seconds on out and 20 in with cylinder.

I am wandering if I should

buy new fittings and hoses to get 3/4 hoses from pump to valve / valve to cylinders , the issue here is the all have 1/2 ports...

Is it possible valve is malfunctioning, allowing fluid to bypass to return line? Seems when I move valve in or out to extend and retract cylinder the flow to return line slows but not completely off.
Right now I am at a loss. Fittings check out, hoses check out, push block is loose on beam to ensure no binding. Can generate 3500 psi with valve held open to extend with cylinder fully extended.
Still thinking pump is just stuck in the smaller flow higher pressure mode. Have a 16 gpm coming brande new from northern...

This thing is upsetting me as I feel it should be running great. Thaks for help . Ideas?

 

[kevin j]

5 gallons in 40 seconds is about 7 or 8 gpm.
If a 13 gpm pump was on low flow only, it would be about 3 gpm.

When 7 gpm goes into the closed side of cylinder, about 4 or 5 gpm will come out the rod side due to area differencews. Conversely, when 7 gpm goes into rod side, about 10 gpm should be pushed out of closed side.

1. what is your engine rpm for sure? Pumps are usually rated at 3600 rpm for small engines or electric motors, just by convention. 13 gpm at 3600 would only be 7 gpm at about 1800-2000 rpm.

2. when you cycled it into a pail I presume, did the fluid appear cloudy or milky? If it is cavitation from suction restriction you won't usually see it in the oil, but if there is an air leak you will see foamy oil.

3. Where is the gauge located? What is the pressure in neutral, and with cylinder moving, but without splitting?

4. I would pull out the unloading valve (that you adjusted) and also the check valve (usually behind a fixed hex head plug) and make sure the check valve is not leaking backwards from the small pump section, and that the unloading of the large section is not unloading when it shouldn't.

5. Larger lines WON'T change speed on a positive displacement pump. It only affects the pressure drops to push fluid through the lines. The only exception would be if the pressure drop in the lines was so extremely high that the pump unloaded to small section, low flow.

 

[Aaron441]

Diesel rpms

1. what is your engine rpm for sure? Pumps are usually rated at 3600 rpm for small engines or electric motors, just by convention. 13 gpm at 3600 would only be 7 gpm at about 1800-2000 rpm.
+1 on this. 3600 rpm's seems really fast for a diesel to me. For a gas engine that would be about right, but diesels usually run slower. When I googled Kubota 6.5 horse diesel, I kept coming up with 1800 rpm's, which sounds better to me. I would be checking this out before you spend a bunch of money on other stuff.

 

[CJ1]

Tach the engine and be sure it is at 3600rpm or more, most pumps are rated to 4000 rpm. Most small diesels turn at 3600, when you get to the 50 hp or so they start slowing down in rpms. I have sold 5 25hp 3 cyl kubota's and 1 4cyl at 55hp just this month on hydraulic power units. CJ

 

[mlh29]

a few answers

the engine is a kubota oc60e 6.2 hp at 3600 rpms.

The valve has been adjusted, from 2250 to 4000 psi with same speed, as has the pump,

The pump regardless of pressure doesnt seem to bog the engine so I am thinking it is stuck in the slow/ high pressure mode.

Waiting on another pump to use to try out.

Thanks

 

[mlh29]

I wanted to thank you guys for the help.

I timed all of the fluid outputs, checked those values with numerous sites on the net. It seems that I was only getting about 3.4 gpm out of the old pump no matter what rpm.
I ordered and installed a new 16 gpm haldex 2 stage and am in business again. I now have about a 17 second in and out cycle time with my 4x30 cylinder. Fast enough now to keep me busy, and my kubota diesel can run at half rpm up to 2500 psi, for tough stuff it will run at about 3000 rpm behind the 16 gpm pump at 3000 psi without bogging so the 6 hp seems to run the 8 hp minimum pump fine...

Is there a way to rebuild the original 13.6 gpm haldex or is it scrap?

Thanks again

 

[kevin j]

take the old pump apart and check for junk or damage.

dirt, can be fixed. damge to mechanical parts, it is toast.

they are rebuildable, but parts for a consumer pump are usually more than the pump cost.