Resurrect a neglected splitter

[wbnca]

First post - great forum, I read what I could but couldn't find an obvious solution if there is one?

I have a used splitter that been sitting neglected for 8 years.

It has a Tecumseh H50 engine with perhaps a 11 gpm pump connected to a 4"x24" piston. No model number or date other than it's I beam and has wheels and is hoz/vert. Tank hold 3 gallons and is near full with ATF from previous user. Engine is so, so and backfires now and then. The valve controller was frozen at first still maybe an issue. Occasionally, the pump leaks from the rear. Piston travel is sluggish and erratic. Piston times, going out takes 60 seconds, return is 30 secs. Doesn't seem to want to split any thing as if there's no high pressure?



What I've done:

Cleaned and rebuilt carburetor. Cleaned gas tank added fresh gas. Engine so, so back fires now and then and still runs rich.

Drained hydraulic tank and cleaned internal strainer (was reasonably clean).

Replaced suction hose.

Replaced return hose.

Still using original ATF (Red) seems clean though slightly thicker then ISO-32.
I have fresh 5 gallons of ISO-46, but decided that no likely the problem so will return it.


Home use only, perhaps a cord a year at best in central California.
Mostly California white oak, 18" dia by 16" typical. Perhaps a bigger eucalyptus next year, but many of the oaks are diseased and dying.


I can have it serviced at for $70 an hour plus parts. Or just try a new pump and/or valve unit?

Mostly will get RYOBI electric for our personal needs. I have COPD (ex-smoker) and in my sixties, besides the gas engines are not good for me to be around. Be nice to have the gas unit for the tougher jobs as few as they maybe.

Any suggestions would be appreciated.

wbnca

 

[kevin j]

70/hr is reasonable for a tech who is good, but mostly you can do your self and learn such a simple circuit.

first, get a pressrue gauge on inlet to the valve. What pressure is there when extending, and when it stalls to a log?

single of two stage pump? does it have a hex adjusting cartridge on the side of the pump? that would be a two stage.

Assuming it worked at one time, we will assume the pump size and engine size match.

do you by chance have access to a flowmeter? (ok, a long shot....)
how about a known good hydraulic motor, that could be used as a flowmeter...

Suction side is all clear apparently?

you said valve was stuck, how much force to get it loose, did anythign break?

My GUESS is relief valve stuck open, something broke in the spool valve, or totally shot pump.

Don't buy any parts or call the tech until you do the simple tests first yourself.


k

 

[mga]

60 second travel seems long....

maybe the controller valve is allowing fluid to by-pass, reducing your pressure. kevin j was right about using the gauge to see how much you're pumping. but, if the valve is defective, fluid will just keep running back into your tank.

can you watch the return line flowing in the tank? if there's fluid while cycling the piston, the defective valve theory should be correct.

before dropping $70/hour check things out for yourself.

 

[kevin j]

the return line will be constant flow: 11 (or whatevr) gpm when valve in centered when all pump flow going to tank. Less, maybe 8-9 when cylinder is extending as 11 gpm goes into closed area of cylinder, but less comes out the rod side. Greater, 13-14 gpm when retracting as 11 goes into rod side, but larger area of closed side pushes more oil out.

Pressure gauge reading WON"T tell anything when in neutral, you are correct oil just goes to tank. But if the cylinder stalls and there is not 2500 psi developed, then we know where to start looking for next step.

you can solve it with slow detective, lots of posting, and time.

k

 

[wbnca]

I will post again tomorrow after I refill the tank, I want to run the fluid through a strainer before putting back into the tank. I will add more ATF so that it's 5" deep in the tank that should put 1" above the top of the tank strainer. I will cycle a few times and check the level with the piston fully extended. I can't see the return flow anymore as I removed the poly "clear" return line that was installed which has gotten rigid over time. It never did seem as there was any substantial flow at any time? In neutral I would have expected more. Also as the valve sticks going from extend to retract on occasions in doing so the fluid pops out of the tank vent about 2 oz. Also it back flowed out the vent more so the first days I started it then now, this condition has seemed to have improved. It use to do it when I first got it eight years ago too.

If I stop the engine then move the control from center to retract sometimes I will hear the pressure bleed off. I never heard that going center to extend?
Also what is the travel time for a single stage pump? Would that be about 3.0 gpm flow? So if that's the case the return of about (30 sec) would be normal, but when extending the fact that it is slow to start moving and erratic till it gets past midpoint in travel or under load could be a further clue?

Thanks for the suggestions so far.

A quote for a 5000 psi pressure gage and fittings to install came to about $40.

wbnca

 

[ray benson]

The pressure gauge would be like this (0-3000lb.).
http://www.surpluscenter.com/item.asp?UID=2008031220380793&item=21-1044&catname=hydraulic

 

[cabinman]

Welcome to AS

I will post again tomorrow after I refill the tank, I want to run the fluid through a strainer before putting back into the tank. I will add more ATF so that it's 5" deep in the tank that should put 1" above the top of the tank strainer. I will cycle a few times and check the level with the piston fully extended. I can't see the return flow anymore as I removed the poly "clear" return line that was installed which has gotten rigid over time. It never did seem as there was any substantial flow at any time? In neutral I would have expected more. Also as the valve sticks going from extend to retract on occasions in doing so the fluid pops out of the tank vent about 2 oz. Also it back flowed out the vent more so the first days I started it then now, this condition has seemed to have improved. It use to do it when I first got it eight years ago too.

If I stop the engine then move the control from center to retract sometimes I will hear the pressure bleed off. I never heard that going center to extend?
Also what is the travel time for a single stage pump? Would that be about 3.0 gpm flow? So if that's the case the return of about (30 sec) would be normal, but when extending the fact that it is slow to start moving and erratic till it gets past midpoint in travel or under load could be a further clue?

Thanks for the suggestions so far.

A quote for a 5000 psi pressure gage and fittings to install came to about $40.

wbnca

Wbnca, You should check your tank level with the cylinder retracted, Depending on the shape of the tank, will determine how far down from the top it should be, With only a 3 gal tank and a 4 x 24 cylinder Its a fine line for required fluid level, It would be intresting to see how much fluid is left after the cylinder is extended, If your pump is leaking it might be sucking air, which would explain the eratic cylinder movement, Good Luck Eric

 

[mga]

A quote for a 5000 psi pressure gage and fittings to install came to about $40.

just get a 0 to 3000 gauge. oil filled should be only $15 max.

easy to install on the pump to control valve line. use a "T" fitting just before the valve.

 

[wbnca]

Well I'm back and more confused than ever. I picked up a 2 1/2" 3000 psi gage (fluid) little more than $15 here locally, but not that much more when you consider internet S&H.

But I am still getting nowhere, the pressure reads "0" all the time going out/in, there must be flow or the piston wouldn't move and some sort of pressure you would think.

I couldn't fit the gage at the input to the control valve with the fittings I had, just a "T", so I connected the "T" to the output of the pump. Placed the gage straight up and the "T" going to the input of the control valve.


I hooked the gage to my compressor it does work as it reads 100 psi if I push the regular near the top end.

The motor seemed better at first but sounding worse again and stalls.

When I shutdown this last time I did get pressure to flow (bubbles) into the tank when I move the control to either extend or retract. So I guess the control is working to some extent.


I may have gotten a piece of junk here and neglecting it has gotten even worse.

I could be into a control valve, pump and motor, not to consider a piston?

 

[mga]

could be that the piston seals are just worn, allowing oil to flow past them, or, as mentioned before maybe just a bad control valve.

the gauge was money well spent because you can leave it mounted on the splitter for ever.

can you look into your hyd. tank at all?

when you extend the cylinder...or retract it, is there oil flowing into the tank?

during the extend or retract, no oil should be going into the tank because the cylinder is calling for pressure (fluid) to move, and the control valve, during that time, should be directing all oil to the cylinder.

 

[wbnca]

So would it correct to say the only time you get pressure is when there is a load on the piston as in the case of a "log" blocking the travel of the piston otherwise it reads "0" and you only get flow out the output when it's in neutral?

I should know, I use to calibrate these gages many years ago. We would pump a cylinder to apply pressure till a weight was lifted. The weight and the size of the piston and displacement is converted to pressure.

A technician I contacted about service suggested I put the piston all the way to the extended position, stop the engine, extend the piston farther (I guess by hand) then break the hydraulic input connection at the front of the piston and start the engine and if a lot of oil flows out then the seal is leaking inside. Not sure how this I guess it's relative to the position of the seals internally.

As for flow I've never thought there was much flow under any circumstances.

wbnca

 

[kevin j]

Good on the pressure gauge! I am amazed at people who want free help but won't spend $25 to put a gauge in to test things.

First, there will always be oil going back to tank. In extend, you put say 11 gpm into the closed end of cylinder, but 8 or 9 will come out of the rod end (due to the area difference, steel rod takes up some area.) In retract, 11 gpm into rod end will push out 12 or 14 out of the closed side. At stall, when all pump flow should go across relief, pump flow of 11 gpm will go to tank.

0 psi means either there is no flow, or there is no resistance to the flow. Gear pumps move oil by flow, they don't 'make pressure'. Pressure is a result of a load, resistance to flow.

No flow means pump not turning (but you say it does move).

No resistance means there is a 'hole' in the system so oil goes freely back to tank. Either worn pump, relief valve set too low (but would not likely go to 0)

Push the cylinder to full extend and see what the gauge is. Should be 2500 or so, cylinder is stalled, so oil going across relief valve at it's setting. Can you hear oil going through relief valve?
Just because it reaches 2500 psi does not mean the pump is good though. Pump could be leaking 99% of its flow back around the gears and it would still hold pressure at stall. But start with that test.

To check cylinder, push to full extend, shut off, remove hose from rod end and carefully route it to a bucket or tank. Start up, cycle to extend. If oil blows out, the piston seals are bad. Hose may whip around, be careful. I don't think the seals can be so bad as to leak 11 gpm at almost no pressure, unless the piston had unscrewed from rod. I've seen that, but in extend it should still seal enough to create some pressure on gauge. Unlikely.

checking pump is tougher without a flow meter or a motor. Putting it in a bucket doesn't say too much as there is no load and won't likely leak too much. One thing to chek on pump is that the larger section is actually working. If only the small gear is pumping, the times could be in those ranges, but it should reach 2500 psi when stalled out.

You said bubbles in the tank. If there are air bubbles coming into tank return, there is likely a suction leak. It can suck air in while running but not leak oil out when parked. Air is compressible and things get spongy. Wierd things happen. Should see something on pressure gauge though.

SO: check suction for leaks, check RV by extending cylinder fully, check pump large gearset to see if the unloading valve is unloading all the time.


kcj

 

[mga]

First, there will always be oil going back to tank

why is that? when in the "push" mode, all fluid is directed into the cylinder to give it the force to move and do it's job. if not, the cylinder wouldn't be working to its capability. when the cylinder meets resistance, pressure builds up, giving it the strength it needs to do it's job.

when the cylinder's internal pressure meets or exceeds the control valve's specs, (usually 2500 to 300 psi) the control valve's relief valve kicks in to direct fluid to the tank. this is the safety feature built in. it would only seem logical that this is the only point when fluid is returning, other than when in the "neutral" position.

is this right?

You said bubbles in the tank. If there are air bubbles coming into tank return, there is likely a suction leak. It can suck air in while running but not leak oil out when parked. Air is compressible and things get spongy. Wierd things happen. Should see something on pressure gauge though.

i agree and this should be corrected first.

 

[kevin j]

Q when in the "push" mode, all fluid is directed into the cylinder to give it the force to move and do it's job. if not, the cylinder wouldn't be working to its capability. when the cylinder meets resistance, pressure builds up, giving it the strength it needs to do it's job.

when the cylinder's internal pressure meets or exceeds the control valve's specs, (usually 2500 to 300 psi) the control valve's relief valve kicks in to direct fluid to the tank. this is the safety feature built in. it would only seem logical that this is the only point when fluid is returning, other than when in the "neutral" position. Q



Your understanding of pressure, force, and load is correct. The flow description would be true in a single acting cylinder where the oil goes only to closed end. Say a dump truck lift. Oil just goes in and out of the same port, with nothing on the other side of the piston but air. Double acting cylinder has oil being pushed out of the rod end volume, in the area ratios, so for 11 gpm in for most cylinder bore and rod ratios, about 8 or 9 would be coming back out. Under (ideally) no backpressure just going back to tank. Conversely, when 11 gpm goes into the rod side to retract the cylinder, 13 or 14 gpm are pushed out of the closed side. (The oil that just went in there on the extend cycle has to be pushed back out.)

This area ratio is also why a cylinder will retract faster than it extends. (At least on a simple flow limited logsplitter with gear pump. In a servovalve controlled industrial circuit, the cylinder may retract slower than it extends, but that's a whole nuther topic that even many engineers have a hard time understanding.)

Next week from work I will try and post a powerpoint slide showing single and double acting cylinders.

kcj

 

[mga]

Your understanding of pressure, force, and load is correct. The flow description would be true in a single acting cylinder where the oil goes only to closed end. Say a dump truck lift. Oil just goes in and out of the same port, with nothing on the other side of the piston but air. Double acting cylinder has oil being pushed out of the rod end volume, in the area ratios, so for 11 gpm in for most cylinder bore and rod ratios, about 8 or 9 would be coming back out. Under (ideally) no backpressure just going back to tank. Conversely, when 11 gpm goes into the rod side to retract the cylinder, 13 or 14 gpm are pushed out of the closed side. (The oil that just went in there on the extend cycle has to be pushed back out.)

ahhhhh! i stand corrected. you're absolutely right. i forgot about the oil being pushed out of the cylider when it's being retracted or extended. my bad!

 

[wbnca]

Directions:

Push the cylinder to full extend and see what the gauge is. Should be 2500 or so, cylinder is stalled, so oil going across relief valve at it's setting. Can you hear oil going through relief valve?

Result:

With the cylinder fully extended it read 0 psi.

I don't hear anything over the engine, is there a trick in which to hear the relief valve?


If retract it then extend it again a place an object (log) in it's path once it wedge strikes the log it still reads zero even after waiting 10 seconds.

Followup:

I will cut a small 1' section of 3/4" clear poly tubing into the return line going to the tank so I can observe flow.

Question:

You want me to disconnect from the valve "B" port "swivel-joint" then remove the other end the end of the piston (front) wedge side. I assume this is the cylinder return side. So we are checking to see if it is leaking back through the cylinder through the seal to the return side of the valve?

Would that be a correct observation?

Can't I just remove line from the "B" at the valve side and hang it into a pail?

Could or should there be any flow from the open port at the "B" port on the valve?

In short we don't want to see any or little flow from the wedge input side of the side of the cylinder when it's fully extended.

wbnca

 

[mga]

before doing that, what brand control valve is on there?

go here:
http://www.princehyd.com/Default.aspx?tabid=46

and look at the LS3000 valve. open the "parts manual" to the right of it and when opened, scroll down a few pages. it'll show you a working set up, plus where the relief valve is and how to adjust.

if not your valve, at least you can get a visual of what how it should be.

 

[wbnca]

before doing that, what brand control valve is on there?

go here:
<snip>

if not your valve, at least you can get a visual of what how it should be.

It's a LS-3000

Keep in mind this splitter seemed to work 10 years ago but just sat in the elements since then. The piston comes out clean, retracts rather well now.

Could it be the relief valve is gummed up and is open?

If I count the turns can I just back it out, take out the assembly and inspect it. While it's out maybe shoot a little liquid wrench into the valve as well if it wouldn't contaminate the oil or damage the seals?

I am going to cut in a small section of clear poly tubing on the return side to see flow. It's raining on and off today will try tomorrow.

wbnca

 

[mga]

If I count the turns can I just back it out, take out the assembly and inspect it. While it's out maybe shoot a little liquid wrench into the valve as well if it wouldn't contaminate the oil or damage the seals?

be careful with that relief valve. making it too strong will by-pass the safety feature and could be rather dangerous. i suggest reading about it first.

 

[kevin j]

With the cylinder fully extended it read 0 psi.
***so, either no flow, or a big hole directly from pump to tank. Even bad cylinder seals would not usually leak 11 gpm at 0 psi, I'd expect a coupel hundred psi or more.

I don't hear anything over the engine, is there a trick in which to hear the relief valve?
****At full pressure, you would hear flow and squeal at the RV in the handle valve. But at 0 psi, won't be much noise.


If retract it then extend it again a place an object (log) in it's path once it wedge strikes the log it still reads zero even after waiting 10 seconds.
****Good, confirms the 'no flow, or big leak' even is sucking air, it would slowly buld some pressure.

I will cut a small 1' section of 3/4" clear poly tubing into the return line going to the tank so I can observe flow.
*****could help to see any bubbles, but if flowing properly, you won't see much as the fluid should be pretty clear and steady. Can't really gauge amount of flow anyway.

Question:
You want me to disconnect from the valve "B" port "swivel-joint" then remove the other end the end of the piston (front) wedge side. I assume this is the cylinder return side. So we are checking to see if it is leaking back through the cylinder through the seal to the return side of the valve?
Would that be a correct observation?
Can't I just remove line from the "B" at the valve side and hang it into a pail?
****Yes, sorry, my notes were not clear. With cylinder fully extended, disconnect the rod side hose at the valve is better. then put it in the bucket. Plug the valve port. Drive cylinder extend against end of stroke. If anything comes out of the hose (from the rod end port) the seals are leaking.

Could or should there be any flow from the open port at the "B" port on the valve?
****Yes! the tank line will be maybe 10 to 20 psi (may not be enough to read on gauge) just due to filter and line drop, so lots of oil will come out the port instead of going back to tank. Plug the valve port. In this business you will get wet! Just don't want to get hurt, whipped with hose, or get any oil injected under skin.
*****OT, but ANY injury with oil injection under skin should be treated by a doctor who knows industrial safety. The family doc will clean it and send you home. Petroleum oil attacks the fatty acids of the body tissue and can go to serious gangrene like injury in hours. Had a crew guy end up with entire arm from hand to shoulder opened up like a filleted fish to clean out the injury. Started out as a minor puncture wound in his hand palm with an o-ring pick. Within 8 hours he was at hospital, within 24 had been helio airlifted to a major metro hospital and opened up. Saved the arm, but permanent injuries.

In short we don't want to see any or little flow from the wedge input side of the side of the cylinder when it's fully extended.
****not clear, but we don't want any flow out of the rod end when the closed end is being pressurized to extend against end of stroke, so pressure rises up.

*****I am betting it is NOT cylinder seals unless there was serious rust/corrosion that tore up the seals. Simple wear should not leak that much at almost no pressure.. Likely the relief valve stuck open, or the pump unloading and check are stuck open (even there, should go to high pressure on the small section), or the pump shaft/coupling/keyway/crankshaft key are not turning the pump with a load. Or internal to pump, if key sheared, or broken shaft...anythign that does not drive the pump under load.

****Such simple circuits, so many new and creative things to go wrong!


kcj