# Splitter tech questions--(update on new parts)



## Yule log (Mar 13, 2008)

I have a 20+ year old Didier log splitter that I think it is rated at 20T.  It has a fresh 6.5 hp Briggs.  I would like to repair/upgrade some parts.  

First off, my brass ram guides are worn.  I would like to make some new, sturdier steel slides.  I understand the brass keeps it from binding so I expect to have to use lubrication on the beam from now on.  

Second, my valve is worn to where it won't auto return when I push the lever back. I am looking at a 2 way detent valve in Northern Tools.  I assume when you push the lever in either direction, it will autocycle (not just on the return stroke like my current valve).  Is this correct?

Third, I am considering buying a new pump.  I assume my pump is rated at 11 gpm.  My cycle time is slower than I would like (20 or so seconds).  With a 6.5 hp motor, would I be able to use a 13.6 or even a 16 gpm pump?  I split hardwood-mainly Ash and  Hickory.

Last of all, Northern has a four-way, slip on splitter head.  I am wondering if I could use this on my splitter for mid-sized Ash and smaller Hickory.  If I did try the four-way, would a higher volume pump be out of the question?


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## Highbeam (Mar 13, 2008)

Supposedly Briggs overrates their engines such that the 6.5 B&S;would be the right engine for an 11 GPM pump.


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## mikedengineer (Mar 13, 2008)

Just a thought. As oppose to brass, what about using a bronze impregnated with oil? Look on mcmastercarr.com on catalog page 3622. This is sometimes used in tool and die for wear surfaces.

-Mike


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## kevin j (Mar 13, 2008)

First off, my brass ram guides are worn.  I would like to make some new, sturdier steel slides.  I understand the brass keeps it from binding so I expect to have to use lubrication on the beam from now on.  
****do you mean the guides on the WF beam for the slider, or the actual cylinder rod bushing? The slider can be steel on steel, no worries for the amount of cycling a home unit gets. If possible, have a bolted sandwich with a bit of shimming so if things wear a lot, shims can be removed, but even that is not required. Slop some gear oil on occasionally, or better yet is use dry molydisulfide spray lube. This is an extreme pressure lubricant film that dries solvent free so it does not attract and hold dirt. Wood is not too abrasive. Dirt held by oil become grinding compound. CRC makes one, Grainger.   Clean up the beam and spray some on once a day or so..


Second, my valve is worn to where it won’t auto return when I push the lever back. I am looking at a 2 way detent valve in Northern Tools.  I assume when you push the lever in either direction, it will autocycle (not just on the return stroke like my current valve).  Is this correct? 
*****I would NOT use a two way detent, for safety reasons. There is no deadman return to stop in the extend direction. Not good. For a larger woodlot machine the two valve autocycle setups are nice,  but there the operator is safely away from the wedge area. 
     Two way detent is different than detent with kickout. I don’t know that there could be a kickout in extend because as soon as it hits log and pressure goes up, it would kick out. So it is likely a pure detent, and will stay detented, going across relief, forever until you bring back to neutral.
 Detent on the return direction has a kickout function as normal return is maybe 300 psi or something. When it hits end of stroke and pressure rises, the kickout operates at maybe 500-1000 psi.
     If it does not kickout now, the issue is likely not the valve at all. It may either be adjusted too high, or pump relief valve adjusted too low, such that the load pressure never gets high enough to allow the kickout to work properly.
     Could also be a sick pump leaking most flow around the gears under load. Does it split ok?
     Get a pressure gauge in the line and read what it peaks at in stall, extend direction. This is the relief valve setting, and should be say 2500 psi. See what it does in stall on retract.


Third, I am considering buying a new pump.  I assume my pump is rated at 11 gpm.  My cycle time is slower than I would like (20 or so seconds).  With a 6.5 hp motor, would I be able to use a 13.6 or even a 16 gpm pump?  I split hardwood-mainly Ash and Hickory. 
*****Barnes 11 and 13 gpm pumps have the same small section.  .194 cubic inches per revolution.  At 3600 engine rpm, this small section is about 2.7 gpm. At 2500 psi, that is slightly under 5 hp. So either the 11 or 13 would work fine.
     The 16 has a small section of .258 in3. At 2500 psi that is 6.5 to 7 hp, too big. 
     Large section doesn’t really matter, as the high flow 11-13-16-22 etc can simply be dialded down on pressure to not exceed the engine hp. It just lowers the pressure at which the larger section unloads. So instead of unloading at 700 psi, it unloads at 500 psi. Less force at high speed but not really giving up anything. If the small section were too big, the main relief would have to be set lower to not overload the engine. Running the .258 small section of the 16 pump at say 2200 psi would allow the engine to turn it, but you give up splitting force. Not want to go there.   (Force is operating pressure times cylinder area.)
    I’d go 13 gpm pump if you know for sure it is .2 inch3 or less in the small section. If it is someone other than Barnes, then need to get vendor literature.



Last of all, Northern has a four-way, slip on splitter head.  I am wondering if I could use this on my splitter for mid-sized Ash and smaller Hickory.  If I did try the four-way, would a higher volume pump be out of the question? 
****no relation.  As above, the small section at 2500 psi to the cylinder defines the maximum force. As long as you have enough engine to keep the small section running at 2500 psi, you get max force to try the 4 way. If you go to 16 gpm and have to bring the RV down below 2500 psi, you lose force.

     I’d go with the 13 pump and try the 4 way. But before buying pumps, get a pressure rating on the system, look at suction line cavitation, and get the valve working right. Flow might be going somewhere else as 20 seconds seems slow. What size cylinder?


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## Yule log (Mar 14, 2008)

Kevin and others...thanks for all the great information.  

Not sure on the cylinder size.  I will check tomorrow.  As far as the valve goes, it is on its last leg.  The original links that allowed the handle to pivot forward and backward are long gone so I make new ones out of thin flat steel every year.  The thing has lots of play in it.  

One thing I've thought about with the whole pump system is the size of the tank.  It holds just enough to fill the cylinder.  When it gets worked hard, the fluid really gets hot.  I wonder if this induces air into the system and causes the possible cavitation.  

Yes as far as the brass (or maybe bronze) pieces, these are what cradles the beam.  The shim idea sounds like a good one.  

One more question, how important is it to have a hydraulic fluid filter on a small splitter?


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## kevin j (Mar 14, 2008)

Is the valve spool in the bore actually worn, or just the linkage?   Soem valves use roller chain master links for the linkage. If the bore is good, I'd just rebuild linkage with better parts, and maybe a couple o-rings in the body.

Reservoir, bigger is better. 3 to 5 gal is nice for a small pump. The 'rules of thumb' of 1x or 3x pump flow are more for stationary industrial equipment and mobile equipment is way smaller usually.   Tank is for deaerating oil, some settling, and cooling. Fast speed through tank also tends to aerate the oil, or at least not release the dfissolved air very well. 

Filter, essential, put on the return line not on suction. lack of filter causes long term wear frm circulating the micon sized particles that act as grinding or lapping compound. 10 micron particles that cause wear are about the size of red blood cells, so the old 'looks clean to me' is meaningless.
Lackof filter may explain the worn spool bore and worn pump.

k


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## Redox (Mar 15, 2008)

Kevin, you sound like you know about hydraulics.  Maybe you can answer me a question?  What is the differnec between an "open center" and a "closed center" valve?  Which is appropriate for a tractor driven splitter?  I have asked all the tractor gurus I know, and haven't gotten a good answer.

Chris


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## kevin j (Mar 15, 2008)

tks, yes I design them for a living.
I was referred ver to these boards as I am building some splittes, love saws and splters, and tyring to help out with hydr Q's as they seem to the beh weak point for most people. Mechancal is easy to see, the hydr takes some understanding.
  Inprocess of writing a free website (www.buildyourownlogspliltter, with or without dashes, but it's not up yet)    , so much of what I write is either pasted in from that wrk, or written and will be used for the site.

Basically, open center is used with fixed displacement, constant flow pump. Flow must go through the center and back to tank when not used, or it will go across relief.    closed center blocks the flow atneutral and requires a variable pump that destrokes to no flow when not needed.
    Closed center is easier to put valves in parallel and add more funciton slater. Like plugging things into a wall outlet, jsut add more on.

I will try and post a little slide from power point showing eachone. They are in some presentiaions I have at work, related to our railroad machines.   If you don't see them next week PM me a reminder. Moving offices thise weekend so I hope the computers are up oon Monday.


This post below is very good. He is describing a 'load sensing' closed center which is very slightly different than a straight pressure compensated, but is newer and the most commmon on farm tractors and construction equipment.I pasted it into my files from a post on the Ag machinery talk BB. Thats a good site for farm machinery. Also try the machine builders net BB.

kcj


Someone else’s post on Ag Talk board
OPNE CENTER CLOSED CENTER

The main difference between the two is the hydraulic pump. There are a very few exceptions to the rule, but in 99% of today's agricultural hydraulic systems. 

OPEN-CENTER (OC) 1- the pump is usually a gear-type pump with a constant or "fixed" displacement, 
2-the gear pump puts out a constant volume (fixed displacement) of oil for every revolution, 
3-the pumped oil goes through a system of "open" valves that do not internally restrict or divert the flow of oil until the valve is activated, so the hydraulic system stays at a relatively low pressure until a valve is activated. 
5- The pressure rise in the system is caused solely by the resistance of the hydraulic work to be done (i.e., the weight of the disk harrow against the hydraulic cylinder raising it) 
6- when the work is done, the open center valve is returned to neutral, and the oil flow through the valve is unrestricted once again. The pump's flow doesn't change from neutral to full pressure; just the pressure in the system changes. 

CLOSED-CENTER (CC) 1- the pump is an axial-piston pump with a control device (compensator) which can vary the pump’s output from almost nothing to maximum volume. 
2- The pump's output per revolution is variable, depending on the "demand" fed back from the hydraulic system valves to the pump compensator 
3- the pump's output flows to a system of "closed" valves that internally stop all flow through the valve until the valve is activated. 
4- the hydraulic system's flow and operating pressure vary, and is determined by the load at the moment, which can be relatively low or very high 
5- the pressure rise in the system is also chiefly determined by the resistance of the hydraulic work to be done, but this is exactly matched to the system's demand by the compensator, 
6-when the work is done, the closed-center valves return to neutral, oil flow is shut off once again, and the compensator instantly adjusts the pump's output to match current system demands. 

This explanation is over-simplified; I am not trying to get into the physics and engineering of even the oldest open-center hydraulic systems, let alone today's complex variable flow systems. 

In brief you most likely will damage an open-center hydraulic system if you connect the remotes to a closed-center application such as that 455 drill, without getting the special kit to divert OC remote valve flow.


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## Redox (Mar 16, 2008)

Thanks for the info!  Does anyone know if John Deere tractors are different?  Somewhere I read that they use a different valve.


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## Yule log (Mar 17, 2008)

Well, since I managed to harvest a good amount of wood this week, I went ahead and shot off an order to Northern Tool becuase I have a lot of splitting to do.  Thanks to Kevin's advice, I went with the 13.6 gpm pump and new valve.  I also ordered a larger hyd resivrior.  The current one only held about a gallon.  I replaced it with a 2.8 gal tank.  I would have liked to have gone a bit larger but my splitter frame is limited on space.  I also bought a filter and 4-way splitter head.  The bill was more than I wanted to spend but then I realized the amount is probably equal to what one months utility bill would be in the winter if I didn't work my butt off to heat with wood.  Wasn't hard to rationalize the purchase after thinking of it that way.


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## boostnut (Mar 20, 2008)

Yule, I also have a 20+ year old didier that has a junk valve (no auto return). I'd like to hear how your 4 way works out, I'm not sure if mine has the power to push one. Mine spent a little time in the shop this winter. Here are a couple of pics of the "new" didier. No more working on my knees.


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## boostnut (Mar 20, 2008)

here is another.


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## Yule log (Mar 21, 2008)

Boostnut, nice looking conversion.  It's neat to take something like a 20 yr old splitter and make it as good as a newer version.  Is that the original motor?  

At 6'3", I too hate bending over.  For now, I'll put the splitter up on jack stands and the wood will be caught on a table instead of hitting the ground.  I was going to weld up a "catcher" like on some high end models but my uncle, the family mech eng., suggested I take a junk wooden table that he had to see what type of set up I should go with (length/width etc).  I will take a pic tonight.  It has that ultra-custom, redneck engineering look to it.  Once I get all my parts installed (UPS is coming today!) I will let you know how the 4 way works.  I'll be excited to just have a valve that auto cycles back.

Btw-regarding the bronze beam guides, I took them off and barely touched them with my angle grinder.  I took them down a 1/16th to get rid of the grooves.  This seems to have worked.  I don't have any side to side play anymore.


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## boostnut (Mar 21, 2008)

Yep, original 5 hp briggs. Seems like it uses as much oil as it does gas, I dont think its got much life left in it. The pump, beam, wedge, and cylinder are also the originals (although the wedge isn't reckognizable after my modifications). Yours must be a little different than mine as I dont have any bronze guides, just steel on steel. Overall I'm very happy with the changes I've made. I would highly suggest making at least a simple change to get the work height to a comfortable level (especially if you're 6'3"). Good luck!


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## Yule log (Mar 27, 2008)

Well, all the Northern stuff came in last week. I spent part of the day on Saturday slightly modifying and attaching the new tank, adding the new valve, pump and connecting the filter. I had to make a few trips into town to visit Tractor Supply because the valve ports were opposite of the ones on the old valve so the cylinder went in when it was supposed to go out. I split a couple pieces with that configuration. Didn't do it long because it seemed like a good way to lose a finger from the confusion in direction. I ended buying new hyd lines because the originals were metal and thus would not fit the new configuration. 

My learnings...the 13.6 gpm pump is great. My old cycle time was 20 seconds and now it comes in around 10 seconds. I have lots of power all the time now. The large 2.8 gal tank makes a big difference also. Before, the old tank would get very hot. Now I can place my hand on it and it is lukewarm. I figure the extra volume of the filter doesn't hurt either. I've put about 5 hours on the splitter this week and everything works great. The 4 way head works good on round pieces up to 10" or so (it is the 8" type). Anything above that doesn't split as well because the horizontal wedges don't extend out far enough to make a complete split. I am still glad I bought it though. On the midsized stuff, it makes things go that much faster. The splitter has no problem splitting Hickory 4 ways. Actually, the Hickory seems easier than Ash because it splits all the way through. The Ash sometimes needs to be pulled apart after the cycle.


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## jsausville1 (Sep 6, 2008)

I have an old didier logsplitter too.  Its a great little machine and it hardly ever gives me trouble.  However I broke the bracket on the handle control that allows the valve to go in and out.  The part number is 4z4306.  Anyone know where I can find a replacement?


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## Ozarknana (Sep 8, 2008)

We too have an old Didier and are looking for some parts, hopefully someone will come along and let us know where we can get them.  Searching with google has gotten us zero!!

Ours quit pushing and is leaking hydrolic fluid all over the place!

(sorry to of hijacked your thread) :zip: 

Ozark Nana


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## kevin j (Sep 8, 2008)

Most of the parts for any splitter is generic hydraulic industry stuff. Seals and piston seals are typically parker for most US made cylinders. Any good shop can rebuilld them.

what do you need?


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## jsausville1 (Sep 15, 2008)

I found the part by searching for Cross parts and the part number.  The bracket I needed(4z4306) is a standard industry part as Kevin J stated.  There were a number of different companies to choose from who had it.


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