Help diagnosing log splitter problem

[forgero]

I have had a Performance Built 13-ton log splitter I bought at Lowes for about 5 years now which has overall been pretty good for a small operation. Details on it can be seen here: https://www.cnsuperpower.com/produc...lt-13ton-gasoline-log-splitter-half-beam.html.

I had two problems initially. First, the rod took about 5 seconds to get up to full speed. Second, it did not have splitting power after a few minutes of use.

Things I tried: I replaced the hydraulic fluid and cleaned out the filter, which had rubber bits clogging it. I replaced the cap to the hydraulic tank (the plastic cover was cracked). I also replaced the engine oil, however the engine seems to be operating fine.

These two things did not solve either issue so I took only the cylinder to a hydraulic shop mechanic who took it apart and replaced the seals. this solved the issue with the rod being slow which explains why the rubber bits were in the filter. however, it did not fix the issue with the splitting power lasting only a few minutes.

I contacted the manufacturer who suggested I change the pressure setting, which involved removing a cap on the control valve and turning a nut with an allen wrench. this did not solve the issue.

As the cap was new and I had read some things about a lack of airflow possibly being an issue I opened it up and found a spring with what looked like a sponge on the end. I removed this and replaced the cap, now it will run for about 15-20 minutes before it loses splitting power. this made me wonder if its an issue with air intake or overheating, but I know nothing about hydraulics and have no experience repairing equipment.

Before I spend several hundred more dollars on a repair shop, I am hoping the experts on this site will be able to help me figure out what the issue is so either I can fix it myself or decide if its time to hang it up.

I am just about at my wits end, so any help is very much appreciated.

 

[big_eddy]

What do you mean ”it will lose splitting power” ?
Does the ram stop moving? Or just move slowly?
Does the engine slow down or stall when the ram contacts the block?
Does the ram move forward normally until it contacts the block, and then it stops moving instead of splitting?
When the ram contacts the block, does the sound of the engine change as the load increases?
Does the retract function still behave normally.

Splitters are pretty simple systems. Although following your link it says it has a 16 gpm single stage pump. With a 208cc engine, that’s unlikely to work. And if it’s really a 16 gpm pump, with a 1.5 gal hydraulic reservoir, it won’t work for long before the oil is froth.

 

[forgero]

Thanks for the response

What do you mean ”it will lose splitting power” ?

For 15 ish minutes it will split just about anything, after that time the ram will move but once it hits wood it wont split it.

Does the ram stop moving? Or just move slowly?

The ram moves normally, but it wont split anything that gives even the slightest resistance.

Does the engine slow down or stall when the ram contacts the block?

The engine seems to be fine, I have not noticed any bogging down.

Does the ram move forward normally until it contacts the block, and then it stops moving instead of splitting?

Yes

When the ram contacts the block, does the sound of the engine change as the load increases?

Not that I have noticed

Does the retract function still behave normally.

Yes

Splitters are pretty simple systems. Although following your link it says it has a 16 gpm single stage pump. With a 208cc engine, that’s unlikely to work. And if it’s really a 16 gpm pump, with a 1.5 gal hydraulic reservoir, it won’t work for long before the oil is froth.

Is it possible the pump is shot? if it is, why would it function fine then peter out as time goes on?

One thing I have noticed is a distinct high pitched whining sound when the arm is extending where I did not hear it before.

Thank you for your time and help on this.

 

[big_eddy]

Back up and tell us more about the splitter. I'm certain it doesn't have a 208CC engine and a 16gpm single stage pump on it.
A 208cc engine is probably 6HP +/- . A 6HP pump can pump max about 11GPM at low pressure, 3 GPM at high pressure. No way a 6HP engine can pump 16GPM even at low pressure. So what pump is on it? When it is working, do you notice the cylinder "slow down" when it hits the block and drops into second stage ie. slow with high pressure? Or is it just slow all the time?

If the pump is pumping 10-11GPM and your resevoir is only 1.5gal per the spec sheet (and photo), then the fluid is exchanging 8-10x a min. That's 8-10x the recommended exchange rate and 3-4x what all the cheap box store splitters do. Your fluid is going to get hot very quickly and then start to aerate. Aerated fluid can't be pumped. Next time the splitter stops working, CAREFULLY put your hand on the side of the resevoir. If it's burn your hand hot, then the issue is the resevoir is too small for the pump and your oil is overheating. (And the o-rings in your valve and seals in your cylinder likely won't last long)

If that's the issue, its a design problem and you need to modify the splitter to add a bigger resevoir.

 

[forgero]

The manual says the engine is 6.5hp, I checked the model number and it matches this: https://shop.briggsandstratton.com/products/briggs-stratton-engine-packed-single-carton-12.

the pump is a CBK1-F1.6, couldnt find any details on it or the GPM it can output.

When it is working, do you notice the cylinder "slow down" when it hits the block and drops into second stage ie. slow with high pressure? Or is it just slow all the time?

it typically slows down when it hits wood, until it splits then it speeds up again. if its a particularly knotty piece, it can take quite a few seconds to rip through it.

I will do some splitting with it and see how hot the reservoir gets, but I had not noticed it getting hot previously.

it sounds like investing in a new, better quality splitter might be necessary at this point if I am going to continue with this "hobby".

 

[big_eddy]

The pump actually is a single stage pump rated at 1.66ml/ rev which equates to 1.58 GPM at 3600 rpm normal engine operating speed. So a 1.5 gal tank is not bad And should not overheat or aerate the oil.

Gear pumps CBK1-F0.63

Gear pumps CBK1-F0.63

www.zfhydraulic.com

So now we are down to the relief in the valve as the most likely culprit. Maybe when it gets warm, it opens too soon. This would be the Allen screw under the acorn cap. What did you do before, and did it change anything?

Do you have the ability to tee a pressure gauge into the system? It would tell us a lot.

 

[Al Smith]

I would say if the oil is getting hot chances are it's either bypassing in the control valve or the cylinder or the pump is cavitating .It could depend on the pump style which might have a relief valve or use the relief in the control valve . If it's not bypassing on a single stage pump it should nearly stall a 6.5 HP engine .

 

[forgero]

The pump actually is a single stage pump rated at 1.66ml/ rev which equates to 1.58 GPM at 3600 rpm normal engine operating speed. So a 1.5 gal tank is not bad And should not overheat or aerate the oil.

Gear pumps CBK1-F0.63

Gear pumps CBK1-F0.63

www.zfhydraulic.com

So now we are down to the relief in the valve as the most likely culprit. Maybe when it gets warm, it opens too soon. This would be the Allen screw under the acorn cap. What did you do before, and did it change anything?

Do you have the ability to tee a pressure gauge into the system? It would tell us a lot.

The manufacturer had me follow this diagram



I made a few 1/4 adjustments but it made no difference.

I dont have a pressure gauge but I can look into getting one.

 

[davidwyby]

Pressure gauge

 

[r7000]

The engine seems to be fine, I have not noticed any bogging down.

then the pump is not building pressure, it is not transferring engine power to fluid power. U can youtube a vid of some nut running your exact model, you can hear the engine rpm sputter briefly when splitting, which is normal and what should be observed.

For 15 ish minutes it will split just about anything, after that time the ram will move but once it hits wood it wont split it; The ram moves normally, but it wont split anything that gives even the slightest resistance.

so if it does function well at some point... when cold... then I would say the pump is not shot, nor do you need to adjust a pressure setting. Given after X minutes of operation, the hydr. fluid will heat up. If it gets too hot then viscosity is too low and pump pressure will be reduced but should not be to the point to not splitting anything. Since there seems to be no force available... then a pressure gauge likely won't be of any use it'll be a very low reading. It would not be a bad idea to check fluid temperature to know, get a $10 digital meat thermometer from amazon.

I replaced the hydraulic fluid and cleaned out the filter, which had rubber bits clogging it

I'd bet $1 that debris got into the tank then made its way to the pressure side and it's hanging up something either at the pump pressure relief valve or in the control unit, either clean out or replace each. And as the fluid gets hotter then that leak will become worse.

 

[big_eddy]

The thing we are struggling with is this is not a normal splitter design. The manufacturer has done something funky with a spring return. Just look at how the reservoir is plumbed. And the valve is a rotating valve, not a standard spool valve. So not everything we “know” even applies in this case. It’s more like a hydraulic bottle jack laid on its side. Pump provides pressure to the base to split, open up a base valve to return with spring force.

I’d love to see a parts breakdown of the cylinder and valve. It might answer some questions

I'm now thinking one of the o-rings on the valve core leaks as the temperature increases, not closing the return path from the cylinder base. Just like if you were to try to jack something with a hydraulic jack with the drain valve open. That allows the oil to bypass back to tank. That would explain the no pressure without lugging the engine.

Not really knowing how the valve is designed makes it hard to go much farther.

 

[davidwyby]

Restriction on supply to pump?

 

[forgero]

Thanks for all the replies.

I finally got a chance to do some splitting today, about 20 minutes in it stopped splitting. nothing feels hot to the touch, the fluid in the reservoir is not hot. the pump itself is the only part that feels slightly hot, but not so much I cant hold onto it.

I'd bet $1 that debris got into the tank then made its way to the pressure side and it's hanging up something either at the pump pressure relief valve or in the control unit, either clean out or replace each. And as the fluid gets hotter then that leak will become worse.

would the mechanic that took apart the cylinder and replaced the seals not have cleaned that out?

I'm now thinking one of the o-rings on the valve core leaks as the temperature increases, not closing the return path from the cylinder base. Just like if you were to try to jack something with a hydraulic jack with the drain valve open. That allows the oil to bypass back to tank. That would explain the no pressure without lugging the engine.

Not really knowing how the valve is designed makes it hard to go much farther.

I attached pictures of the control valve. it looked pretty clean inside, im not sure how it would be leaking unless its just poor design?

when I had the mechanic look at it, he told me he could order a brand new cylinder for about $350ish, what is the best guess likelihood that replacing it would fix my problem? $350 would beat buying a whole new splitter.

 

[davidwyby]

The cylinder is not related to the control valves. Cylinders generally either work or don’t.

 

[Al Smith]

I must say that's a very unconventional design .If I am following this thing the ball check valve controls the pressure .If the "seat " for the ball is out of kilter it will not seal correctly as the oil heats up .Face it with this design it's like making a silk purse from a sows ear .
As far as fixing it you might be able to use spacers ahead of the spring and crank the ball tighter down on the seat. . If so designed change the entire valve assembley if it's removable from the cylinder .

 

[Al Smith]

Now then on the other hand if the cylinder is getting noticably hotter as it runs that would indicate the cylinder piston rings/seals are failing .If so designed those might be able to be replaced .

 

[forgero]

The cylinder is not related to the control valves. Cylinders generally either work or don’t.

the control valve is seemingly attached to the cylinder, so it would all come in one piece I believe. I should have been more specific.

I must say that's a very unconventional design .If I am following this thing the ball check valve controls the pressure .If the "seat " for the ball is out of kilter it will not seal correctly as the oil heats up .Face it with this design it's like making a silk purse from a sows ear .
As far as fixing it you might be able to use spacers ahead of the spring and crank the ball tighter down on the seat. . If so designed change the entire valve assembley if it's removable from the cylinder .

it doesnt look like its removable, seems like its welded on.

Now then on the other hand if the cylinder is getting noticably hotter as it runs that would indicate the cylinder piston rings/seals are failing .If so designed those might be able to be replaced .

nothing gets hot to the touch, and the fluid isnt hot either.

maybe its a lost cause at this point and I need to decide if its worth buying a new one or if I should retire.

 

[davidwyby]

I re-read the OP and looked at the link. It's goofy. I bet another piece of rubber is floating around and holding a relief valve open. A pressure gauge on a tee would tell a lot. One after the pump and before the control. That will tell if the pump is working. One after the control valve and before the cylinder....probably can't do that since it looks like the control block feeds straight into the cyl. But if the cyl isn't moving, and the tech rebuilt it right, it's not getting pressure. maybe more junk in the res. With it being on top, the junk is gonna get down into everything else.

 

[davidwyby]

Have you talked to the hyd shop?

 

[Woodpecker]

Have you talked to the hyd shop?

Seems like a good plan to me. It’s reasonable to go back to them and say “hey this is still acting up” See if they will take care of you.