Log splitter will only split at low engine RPM

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I'll take your advice and crack it open tomorrow morning before taking to the shop
My advice would be to clean the pump up good before tearing into it, then clear an area on the bench and lay out a light colored clean towel...a lot harder for any small parts to roll away on a towel...plus it will help soak up the inevitable oil mess. Anytime you take another piece off keep a little tension on it releasing it slowly so to be ready for the surprise spring popping out...a good practice in general when tearing into something for the first time.
There is probably not as many small parts in this unit as you think. Hopefully there is not small parts that used to be big parts! !!!
 
I assume these little pistons should be treated like lifters in a motor, make sure you track clocking and location of each one, so they go back into their respective bores in the same orientation? No experience with these pumps, so this is a question. If my assumptions are correct, get yourself some egg cartons for keeping the parts oriented.
 
I tried to take it apart this morning, but the allen head screws holding on the solenoid-looking-thing are stripped (wasn't me), so somebody with a set of extractors and replacement screws will need to address that. I could always grind the heads off but at this point I don't want to accidentally damage anything else. So off to the shop it goes, probably this afternoon.

When I turn the pump by hand, it actually gets in a bind. I have to turn it in reverse to get it un-stuck and then can turn it a bit more.
 
It almost sounds like it either swallowed something or a bearing came apart. You could try flushing it out with Kerosene and see if anything washes out.There shouldn't any springs that fly when you open it up.

Here is a link that may help give you an idea of what is inside. If you can find a model # that will narrow it down. It seems like there was a tag riveted on the body with the information,
https://www.google.com/search?q=vic....1.69i57j0.28413j0j7&sourceid=chrome&ie=UTF-8

It's been the better part of 30 years since I've been into one so I'm working from memory.We used to run them on the Bucket trucks when I was at the tree company. They were a very reliable well built (and expensive) pump.
 
if it’s a Vickers PV pressure compensated pump series you’ll need to determine whether it’s been running with an open center valve or a close center valve. they typically should be run with the close center valve because they’re quite sensitive to inlet suction condition and to running with no pressure to keep the Pistons against the swash plate. I wouldn’t put any money into fixing it personally. I think that aeration and suction condition was damaging it but you will need to determine if the valve is closed or open center before putting a gear pump on there.
 
case drain always goes out the highest position so that the pump stays full of oil and itself purges air out of the case. The PV Vickers is really sensitive to the difference between case pressure and suction pressure. they tend to rattle their slippers against the swashplate if they’re not under load and if there’s a high suction condition.
 
I agree Kevin, just do an autopsy and see what it died of. Given the age probably not worth fixing. Do some plumbing changes as long as it's down, like pulling the suction off of the bottom of the tank. If you switch to a gear type pump You can use the case drain port on the tank for the vent.
 
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I was never able to get it apart so I dropped it off at Akron Hydraulic yesterday - should hear back from them tomorrow or Friday. The guy said 9 times out of 10 with "older" pumps like these, the customer will just end up replacing it (1970s = old??). Seems like replacement is the consensus here too. But I will let you know the outcome, and will definitely get pictures of the carnage (unless it's something simple that they can repair for a reasonable cost).

So a gear pump is probably the replacement of choice huh. I'd definitely want something that will be able to take full advantage of the big Wisconsin, and wouldn't be as "sensitive" as this one. AND I want to be able to mount it straight to the in/out clutch using the factory flange without any sort of strange rigging. I know that's probably a pretty big ask, as a lot of the homemade splitters I've seen have used Lovejoy connectors.

I think a 5x30 cylinder is what I'd like to get, but that may not be in the cards right now depending on how much the pump repair/replacement costs. I'm not as concerned with "speed" as much as I am with "power". I have a pretty good tolerance for "slow but steady" machinery. I plan to still split the smaller, straight grained pieces with a maul and use this machine for the larger, twisted, wet/stringy, or otherwise difficult pieces.

Also, I finally met one of my neighbors down the street who has a fantastic welding/fab shop. We got to talking and he said we can get together and do any of the plumbing alterations that need welding, cutting, drilling of steel.
 
cultivate than relationship with the neighbor, leads to other good things down the road. Guess you could say I am that same type of neighbor sitting here in my little machine shop full of big boy toys.
 
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Hey, so I had a thought after watching a few YouTube vids. Any chance the 250 on this tag means 250 bar? That would equate 3600+ PSI, and would be in the safe operating range. Yeah, it still says "air", but maybe I'm onto something?
 
Any chance the 250 on this tag means 250 bar?
No, I really doubt it...American made stuff back in the day only used PSI as far as I know...only ever seen bar used on foreign made stuff. And 250 bar air pressure...WOW!
 
Meh

Parker Hannifin is a German company now, and the products on their website are rated in bar. Thought I might have got lucky.

Also cool that Parker was founded in Cleveland, OH.
 
My late dad was a hydraulics design engineer at Vickers until the early 70s and might have designed that pump.

Hope the repairs work out. This has been an engrossing saga
 
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More thoughts:

-Cylinder: 250 is most likely psi. Search on the model number and see what Parker has. It is likely a very old model and probably not on inet. Parker is HUGE in hundreds of markets, not just fluid power.


-Was this a very old machine, running for the previous owner years and years, or something just built recently of old parts? i.e. is it a design issue, or a breakdown issue?


-Did the PO run the engine at partial speed and have satisfactory service?


-The reason all this clicks is that the Vickers PV series piston pumps were rated for 1800 rpm max in the industrial version. In the 80's they came out with an M prefix (say MPVxx) for mobile equipment. Still it was only rated up to about 2200 or 2500 rpm, depending on pump size. (Smaller = faster allowable). M was also heavier cast housing for pressure spiking, but that is not likely relevant here. If you are running the engine at higher than the maximum pump speed, it will cavitate, aerate, and possibly lift the block and suddenly drop to very small flow, and eventually mechanically destroy itself.


RPM limits were determined by two design issues:

1. The fairly restrictive inlet porting in a piston pump compared to gear pump. Flow has to turn 90 degrees, has to be quite small because of area available on the valve plate, and the inlet flow starts and stops with each piston passing the valve plate. All of this means the restriction is high, so speed has to be kept down. As inlet absolute pressure drops, the issue that I brought up earlier with case pressure vs. inlet pressure becomes serious. Hydrostatic pumps have the inlet charged at 300-400 psi to overcome both of these issues.



2. An open loop piston pump has unbalanced forces in the rotating group. That is solved by a big spring in the center of the block. However, as rpm increases, the forces tend to skew the rotating group so the rotating block is not forced perfectly flat against the stationary valve plate. With a very tiny gap, there is leakage, and there is pressure applied to the valve plate in bad places which separates the two surfaces even more, and they lose the seal. It is called 'block lift'. Hydrostatic pumps solve this with the charge pressure system but can still overspeed. Usually, with overspeed and blocklift, there will be a sudden 'bang' noise and the pump output goes down to almost zero. There is massive flow into the case briefly (sometimes milliseconds), case drain gets overwhelmed, the shaft seals can blow or the case can crack. It usually will not reset itself until the pump goes to a very low speed, or maybe shut completely off and restarted. A hydrostatic pump can suddenly lose all engine braking and basically 'freewheel' the machine if it is overrunning down a grade.

Even if they don't lift the block, they can wear oddly on the piston slippers and swash plate and lose sealing efficiency, especially if running with an open center valve and under very light load conditions, (no system pressure holding the pistons and slipper tight together) and no lubrication to the slippers. They really don't like light load conditions, which this might have been if the control valve is open centered.



Does any of this describe what you were seeing?



Open loop gear pumps have a LOT of advantages in simple applications.



-I doubt the pump is feasible to rebuild. Parts will be really old, or probably aftermarket. Eaton/Vickers is way out of the market for those pumps in the industrial world. Newer pump designs are smaller, higher pressures and speeds, faster responses, and way more control options.

The valve plate is not a loose part. The entire cast end of the pump is replaced. Rotating group and front bearing is replaced completely. The swash plate is who knows condition. That only leaves the housing and the shaft.

However, it might be worth sinking more money into it just because of the shaft and mounting issues you'd have to deal with to replace it.



-Mount is likely an SAE A or B, no problem there.



-With the clutch or in & out box, the shaft is probably splined and oil lubricated. Standard SAE splines, likely no problem. However, logsplitter two stage pumps will almost all be keyed straight shafts designed to run directly from an engine via a jaw coupling with no oil bath.



-If you make an adaptor housing of some sort and have a jaw coupling to be able to use keyed shaft pump, you will have to seal the original mounting pad on the pump drive against oil leaking out, and need a stub shaft from spllne to the jaw coupling, and have to control axial movement of that stub shaft, and probably other issues I am missing.



-You could gut the piston pump, put a rear housing on it that has a through drive pad with keyed coupler, and put a log splitter pump on the back. Vickers had rear pad options but somewhat rare in these smaller sized pumps, and I doubt many spare parts are still around in the system without paying hundreds of dollars.



-You could use a two section pump with external unloading and check valves, but I don't think you want to go there.



-Or, you could use a single section, spline shaft pump. Surplus Center will have some selection of these. If you are used to the speed of the old pump single section pump should be fine. That is essentially what you have now. The pump will be at max displacement until it compensates back on pressure. It is not a varying output flow in this application.



-Another alternate, buy a harbor freight engine and pump and sell the other parts. This is probably cheaper than adapting a keyed pump to the existing drive, but more expensive than a single section splined pump to the existing pump drive.

-Either way, you need to verify an open center spool valve, and verify there is a relief valve in the system.



-Overall it is a 'wool sweater project'. Don't pull the loose string hanging out of a hole in a wool sweater. We've all been there with cars, motorcycles, etc. etc. By the time you replace pump, engine, valve, and cylinder, there is not much original left.



-I would get a single section gear with spline drive, put it back in the clutch box, change the suction plumbing, add a return spin on filter, make sure you have an open center spool valve with a relief valve in it, and run it at a very low pressure. With a 6 inch bore you don't need much pressure. The air cylinder may survive, but I am not recommending or condoning it. Get your work done, sell it, and buy a more modern unit with faster two stage pump.
 
Wow, where do I begin!


-Was this a very old machine, running for the previous owner years and years, or something just built recently of old parts? i.e. is it a design issue, or a breakdown issue?

-Did the PO run the engine at partial speed and have satisfactory service?

First, we all know how Craigslist deals go. The guy seemed honest, and this is what he told me, but who knows in all reality. He said it is a very old machine (he actually said 1950s although it's probably 1970s) and that the old man he got it from was the original builder. The guy was getting too old to split his own wood, and traded this machine to my seller for 8 cords of split firewood. I think 8 might be a little inflated, because the going rate for 8 cords of wood round here would be $2000-2500, but maybe.

I believe the pump was originally connected to this engine in whatever industrial machine they came from. They both have the same base color of industrial yellow paint, and then were painted over with a thick green paint. The green paint job is very old (20-30 years by my estimation).

I'd say it was a combination of both - failure due to design and age/wear - and also possibly misuse due to lack of user education!


-The reason all this clicks is that the Vickers PV series piston pumps were rated for 1800 rpm max in the industrial version. In the 80's they came out with an M prefix (say MPVxx) for mobile equipment. Still it was only rated up to about 2200 or 2500 rpm, depending on pump size. (Smaller = faster allowable). M was also heavier cast housing for pressure spiking, but that is not likely relevant here. If you are running the engine at higher than the maximum pump speed, it will cavitate, aerate, and possibly lift the block and suddenly drop to very small flow, and eventually mechanically destroy itself.

Well this lower RPM rating would actually be ideal for this engine. While Wisconsin technically claims the TJD can be run at 3600 RPM, that's a lot for an old twin and I'd never try it. 1800 would be my target RPM, though they only claim 11.7 HP @ 1800. Unfortunately the governor is NOT set to limit the speed to 1800, as it's very easy to accidentally over-rev it when trying to adjust the throttle. As careful as I was (mainly to protect the engine, not even considering the pump), I probably exceeded 1800. And I guarantee the previous owner did it too, because he revved it up a few times during the demonstration. We both likely contributed to the failure of the pump, since there weren't any protections in place.


They really don't like light load conditions, which this might have been if the control valve is open centered.

Yeah, and I did a lot of "idling" while walking back and forth between the wood pile and splitter, and while making cuts with the chainsaw to trim some length off the pieces. Also I had some pieces that cracked right away so the machine hardly had to work at all. Would have never guessed that to be a bad thing.


Does any of this describe what you were seeing?

Yep, sounds about right. Though I never heard any bad noises until the moment of failure.




-Another alternate, buy a harbor freight engine and pump and sell the other parts. This is probably cheaper than adapting a keyed pump to the existing drive, but more expensive than a single section splined pump to the existing pump drive.

Get your work done, sell it, and buy a more modern unit with faster two stage pump.

Nooooo I'll fight to keep this machine as much as I can. If it means modernizing the pump and plumbing, that's fine, but the old industrial engine and overall look of the splitter are basically the only reasons I got it (plus nobody will try to steal it since it looks like "junk").
 
Alright, bit of an update for you guys. Heard back from the hydraulics shop. The pump is completely trashed and needed 6-7 different parts replaced. They can't even identify it so they can't even try to get parts.

So now it comes down to buying a replacement pump.

The tech is going to spec me out a new pump, and needed an answer to the open/closed center question, so he had me test using compressed air. With the control valve in "neutral", air goes straight through into the fluid reservoir. So it's an open center valve.

Now that we know that, I guess we can start discussing pump options. Unfortunately I don't have the old one in front of me yet to be able to tell you whether it's a splined or keyed shaft. Currently, it has a steel coupler mounted to the pump's shaft, which I did not try to remove before taking it to the shop. The clutch itself is in an oil bath, but an output shaft comes out of the clutch through a bearing and the actual connection to the pump is dry. Hope that makes sense.

Here are a couple of pictures of what I have to work with. It looks like the flange bolts are 5 and 3/4 inches on center. The output shaft from the clutch is recessed back in there pretty far, but the coupling (still attached to old pump) takes care of that distance. It also appears the aluminum flange is removable, if necessary, via the 4 Allen head bolts.


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Ideally, I'd want a pump that operates acceptably at 1800 RPM, but could also handle faster speeds if I need the extra horsepower to bust through something knotty.
 
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My late dad was a hydraulics design engineer at Vickers until the early 70s and might have designed that pump.

Hope the repairs work out. This has been an engrossing saga


Hey that's pretty cool. Too bad it's not savable!
 
The new pumps I have seen have an external shaft. That two bolt pattern on the flange is integral with the pump and should be no different than the "independent " mounting brackets that bolt between the engine and pump. The nice thing is the bracket gives bgreater access to your couplers. The pattern should match some new units on the market. Northern tool and hydraulics discounters/surpluses center?

The whole coupling may need replacing a MIGHT be better purchased separately if the SHAFT diameters between trans/pump are different sizes. You will also need a spider(typical) bushing to place between the couplers- order 2 or 3 to have on hand. I do not think this will be a major project.
 
So... going blindly into this, I did a little work trying to spec out a pump for myself, but I'm still a bit confused. Can't seem to find a 2-stage "log splitter" pump that has SAE B and keyed shaft.

One example I found of a single stage gear pump which sounds like it should work, is a Prince SP25A.

So I found these calculators here: http://www.womackmachine.com/engine...and-calculations/hydraulic-pump-calculations/

If I'm shooting for 28 GPM @ 2000 RPM, I need a pump with 3.23 cubic inch displacement (52.93 cc).

1. The SP25A has a displacement option for 52 cc, so that works.
2. Port locations, I'd just have to choose based on how the old pump is.
3. Mounting, SAE B
4. Drive Shaft, 7/8" straight keyed
5. Rotation, Clockwise

Actual model number, SP25A52A9H2-R. That was easy, I thought. Affordable AND made in USA too!



HOWEVER,

The very first calculator on that Womack page is for determining how much HP the engine needs to be to drive a 28 GPM pump to 3000 PSI... it says 58.8 horsepower! I only have 18, and actually a bit less at 2000 RPM. So my 18 HP engine could only build 920 PSI with 28 GPM pump.

I understand this is all theoretical and depends on some other factors - but am I close? How do I approach the horsepower question?

This would work fine with my "Air" cylinder at 280 PSI working pressure, but if I ever upgrade to a real hydraulic cylinder and want to work all the way at 3000 PSI, I don't want to have to change anything else.
 
Also, thinking into the future, I may one day want to have a hydraulic log lift added, so a single stage gear pump is also appropriate for that, right?
 
Changing engine RPM primarily changes pump GPM, and thus ram speed. Splitting force is dependent on engine torque at any given RPM.

As to HP requirements, are these single stage pumps? The requirement you post is roughly double what I see for a two stage pump.
 
Also, thinking into the future, I may one day want to have a hydraulic log lift added, so a single stage gear pump is also appropriate for that, right?
I use the same two stage on mine for the lift.
 
Yeah I was looking at single stage pumps. I didn't come across any two stage pumps with SAE B mounting and 7/8" keyed shaft (just speculating I have keyed shaft instead of splined).

If we're talking about engine torque, the TJD is a torque monster. I'm seeing a spec of 41.3 ft. lbs. at 2000 RPM.
 
Can't seem to find a 2-stage "log splitter" pump that has SAE B and keyed shaft.
Just throwin out ideas here...have a machine/fab shop make an adapter for you.
Might even be able to use the shaft and housing of the old pump as pieces parts to make said adapter...a lil machining and or welding could go a long way to making a common pump bolt up.

I did this when I build my V8 Bronco II. Too cheap to buy the special transfer case adapter housing and output shaft...I cut the shaft off the old trans...and the new...machined a short piece of round stock to fit each shaft (press fit) heated the adapter up red hot, quickly dropped it onto both shafts ("heat shrunk" it on) made sure it was dead on straight, welded 'er up. That was 20 years ago, still going strong today.
For the transfer case adapter housing, I cut the new and the old housing in half, welded a ring (think large 1/4" thick washer...more or less) between the two halves...wah lah...poor mans trans adapter housing! Full disclosure...it worked good...but did have 1 pin hole leak to fix...welding used aluminum parts well enough to be oil tight is tough!