Logsplitter trouble shooting

[The Fred]

Please give us the GPM, we don't do liters.


Even an older gent like yourself JJ can benefit from this simple conversion program and it's free. I use this every day all day at work.

Thanks for helping JJ you are the hydraulics go to guy!

Convert for Windows - joshmadison.com

Regards, Fred

 

[Leejohn]

Are you 100% sure that gear box is a 3 to 1, sure doesn't look like a 3 to 1.

 

[J_J]

I have 2 speeds on the pto, 545 and 760, I was told the pump data at the shop as they have the speck sheet in the cataloge which we consulted looking for the most appropriate pump, working pressure is 200bar(2900psi) with max at 250bar(3625psi) from 1600rpm up over the flow doesn't increase much, no idea about 66% but i don't believe running anything at 100%
I don't have any speck on the control valve only that it has 1/2" ports and is manual spring loaded both ways, no detents,i prefer it like that so that as soon as i let go everything stops and it was something i already had on the shelf.

I've opened the tank filler, oiled the sled with very little difference but i did try to stall the engine by not letting go of the lever as the engine slowed and it didn't stall, just dropped to tickover so maybe that has something to do things as a very slight movement on the hand throttle speeds the engine up quite a bit from tickover. I'm off to try and scrounge some pressure meters.

Derek

What kind of valve are you using, and what is the relief pressure setting?

What is the pressure reading just moving the cyl in and out?

Remove the sled from the cyl and run the rod in and out and tell us the reading.

As far as the pump, what is the cid?

You said it is rated to 2800 rpm.

If the pump is a gear pump, the flow should be about linear.

At half speed, you should get half of rated flow if the pump is good.

If you want speed, and you are using a certain size cyl, then the only way to increase speed is with more flow.

 

[kered]

Are you 100% sure that gear box is a 3 to 1, sure doesn't look like a 3 to 1.

3.5:1 similar to the ones here PTO Gearboxes 20KW You can get them to 3.8:1

LD1
the relief is in the control valve, i reversed the direction A-B ports as to try that but results were the same, no meter so i have no idea what its set at.

J_J
I dont have a meter as yet to test the pressures, without sled connected its still the same, the pump is brand new, obviously some restriction on the return somewhere.
On tickover using the slowest pto speed the pump is probably doing about 500rpm and pumping only 2G/m at most, forward, engine doesn't change but on the return the engine governer cuts in to stop the engine stalling, at that flow rate the 1/2" hoses should be more than enough. If i speed the engine up to about 1200 rpm the engine doesn't slow much but you can still hear it comming under load but only on the return.

Could the pump have a stall speed or minimum speed,? ie too slow or would it just slow to nothing?

Hoses here are not cheap here($30 for a 1/2" 2 foot hose) so i don't particularly want to go change them all again and spend another $150 unless i was sure its the cause.

Again, thanks all for your help and patience.

 

[DarkBlack]

I see descrepencies.
If you watch your push plate front edge, and time it from the beginning of the side straddles to their end I saw 2 agreeing times.
video footage time:
Foward 15-28=13 seconds. 150-202= 12 seconds
The 2 return times were:
35-40 =5 seconds, and 205-210= 5 seconds.
So your return is 2.5 X faster than your forward stroke.

According to your information:
"The cylinder is 90mm diameter with a 60mm rod and a stroke of 600mm"
That should cause a 1.8X return speed increase, not a 2.5X.

Are you sure there isn't other volumetric robbing objects in the rod side of your cylinder?
You understand that returning at 2.5X will take power?

 

[kered]

The video was with the old slower pump
The rod wasn't returned fully every time as i prefer not to hit the stops(either end) if the wood will fit as it wastes time among other things but thats interesting, why should the return be 2.5x instead of 1.8x as its not a proportional valve. Maybe there is something different in the cylinder that i'm not aware of. What are the posibilities? I'm a almost complete novice with hydraulics.

Derek

Edit, i'll time the strokes stop to stop with the new pump and see if its still the same.

 

[J_J]

Aside from the hose sizes, which should match the valve or larger, have you considered the fact that you may have restriction fittings in the flow path that will limit the flow.

This is a restrictive fitting, and some people install them not knowing what they are.

Have you tried removing the hose from the filter and placing it in a bucket and see if the cyl works normal.

Have you did a flow test from the A and B ports to see if the flow is the same?

The flow to the cyl should be the same, but the retract speed should always be faster than the extend speed.

More GPM provide more speed.

I am surprised you have not found a blockage or resistance to the flow before now.

Do you not have another valve you can test the cyl?

A hyd gage would have helped solve the problem a long time ago.

 

[kered]

No fittings like that in the lines, it was the first thing i looked for. No filter fitted as i said earlier.
No flow test from A to B but i did reverse the valve outputs and things were the same.
The retract speed is much faster than the extend.

 

[J_J]

Every hyd system needs a filter.

Most log splitter use about a 10 micron return filter.

Let us know the pressures when avaliable.

 

[Stonehaller]

How big of a fitting is in the tank for the drain line from the valve? I still think there is a restriction in the drain line somewhere. You may want to post several close up pictures of the valve and the various hydraulic connections on the splitter to see if someone here can spot something.