Slow Cylinder Cycle

[rich5556]

Hi,

I was wondering if anyone had any advice on the problem with my new log splitter. It has a huge cylinder- 45 ton - and an 8hp honda motor. A 18 gpm oil pump. I was wondering if I needed to upgrade the hp on the motor because it takes about 30 seconds to extend and 30 seconds to retract. Any advice would be greatly appreciated.

 

[brenndatomu]

With a cylinder that size you will need to upgrade to a larger GPM pump, that is the only way to decrease cycle time without changing to a smaller diameter cylinder. The problem is that with a larger GPM pump comes the need for more horsepower, quite a bit more.
I'm sure that once people realize that AS finally got ahead of that stupid Linkxxcks attack :mad2:, the resident hydraulic experts will chime in and give you some actual numbers...

 

[513yj]

The cylinder appears to be a little large for those hp and gpm pump numbers to cylce very fast. Might be cheaper to think about downsizing to a 35 ton ram.

 

[rich5556]

The cylinder appears to be a little large for those hp and gpm pump numbers to cylce very fast. Might be cheaper to think about downsizing to a 35 ton ram.

I have a 13hp engine, would attaching it to the same gpm pump increase my cycle time?

 

[Whitespider]

NO.
You need to move more fluid to increase (off load) cycle time, a 13 HP engine won't spin the pump any faster than a 8 HP engine... most all small engines turn at the same 3600 RPM's (give-or-take).

 

[gulity1]

45 ton?? how did you get to this number kinda sounds a little fishy?? your math or the sticker on the splitter I only question this becasue we all know that the manu. are always honest when they print the stickers...Right. Can we see some pictures of the splitter in question, I have a TSC Husky, speedco splitter with a 5"ish cylinder a crapy techemsa engine on it ( hate it) a 12? GPM pump and I get about 20-30 total cylce time maybe and its all I really want for extended periods of time. Measure the outer DIA with a string transfer the string measurement to a tape measure and divide by 3.14 that will give you diameter of the outside of the case most cylinders .25 wall or there abouts so it will give us a close number to work with, from there we can figure out everythiing else I am willing to bet either restiction or bypassing in the cyclinder. My money is on restriction though. Is the cylinder or tank hot and I mean hot, cant touch it hot? No matter what it is we will help get it right and going properly looking forward to this.. Adam

 

[rich5556]

45 ton?? how did you get to this number kinda sounds a little fishy?? your math or the sticker on the splitter I only question this becasue we all know that the manu. are always honest when they print the stickers...Right. Can we see some pictures of the splitter in question, I have a TSC Husky, speedco splitter with a 5"ish cylinder a crapy techemsa engine on it ( hate it) a 12? GPM pump and I get about 20-30 total cylce time maybe and its all I really want for extended periods of time. Measure the outer DIA with a string transfer the string measurement to a tape measure and divide by 3.14 that will give you diameter of the outside of the case most cylinders .25 wall or there abouts so it will give us a close number to work with, from there we can figure out everythiing else I am willing to bet either restiction or bypassing in the cyclinder. My money is on restriction though. Is the cylinder or tank hot and I mean hot, cant touch it hot? No matter what it is we will help get it right and going properly looking forward to this.. Adam

Hi Adam,

Thanks for your response. I measured the circumference and it was 18.5" dividing it by 3.14, the diameter is 5.89". We've never run it for over a couple minutes so the cylinder was not hot to the touch. Thanks for your help.

Richard

 

[wndwlkr]

The pump is your restriction, looks like a 16 gpm & they only have 1/2 " out so your stuck there to start with. looks like a 6" cylinder so you can expect slow cycle times. Just for reference I finished a build today with a 16 gpm pump & a 212cc motor & it works great. All the hype about 8 hp to run 16 gpm is false in this case. It will split wood idleing.

 

[rich5556]

The pump is your restriction, looks like a 16 gpm & they only have 1/2 " out so your stuck there to start with. looks like a 6" cylinder so you can expect slow cycle times. Just for reference I finished a build today with a 16 gpm pump & a 212cc motor & it works great. All the hype about 8 hp to run 16 gpm is false in this case. It will split wood idleing.

Thanks for the response. This is the first log splitter we bought by pieces vs. complete sets so please excuse my lack of knowledge. Would you recommend any particular GPM for a new oil pump that would help us reduce the cycle time?

Thanks again,
Richard

 

[rich5556]

Thanks for the response. This is the first log splitter we bought by pieces vs. complete sets so please excuse my lack of knowledge. Would you recommend any particular GPM for a new oil pump that would help us reduce the cycle time?

Thanks again,
Richard

Also, if anyone had any recommendations for a vendor or a certain brand that had a great value to quality proposition, I would highly appreciate it. Thanks guys, really appreciate all of your help.

 

[triptester]

First ,the tonnage marked on the cylinder is advertizing BS. The O.D. of the cylinder would translate to a 5.5" bore which at 3000 psi would produce 35.6 tons of working pressure.

If the pump is rated at 16 gpm at 3600 rpms, when the rpms are lowered to 1800 the pump will only produce 8 gpm.

Things that can xcause longer cycle times

A stuck open relief in the control valve.
A partially stuck open bypass in the pump.
Low pump rpms.

 

[rich5556]

First ,the tonnage marked on the cylinder is advertizing BS. The O.D. of the cylinder would translate to a 5.5" bore which at 3000 psi would produce 35.6 tons of working pressure.

If the pump is rated at 16 gpm at 3600 rpms, when the rpms are lowered to 1800 the pump will only produce 8 gpm.

Things that can xcause longer cycle times

A stuck open relief in the control valve.
A partially stuck open bypass in the pump.
Low pump rpms.

Thanks Triptester. I checked out your calculations on the working pressure and it looks like you're right.

Would this be the right way to think about cycle time?
Volume of cylinder = pi * radius squared * height

volume = 3.14 * 2.75^2 * 26 = 617.4 cubic inches
1 cubic inch = 0.00432900433 gallons

617.4 * .00432900433 = 2.67 gallons

16 gpm pump @ 1600 rpm = 8 gpm

2.67/8 = .334
.334 minutes = 20 seconds

so complete cycle = 40 seconds

I'm honestly a complete newb when it comes to log splitters but I'm interested in learning. Any tips on how to check out open relief in the control valve or the open bypass in the pump?

Thanks so much guys. I'm learning a lot here and appreciate your help.

 

[rich5556]

Thanks Triptester. I checked out your calculations on the working pressure and it looks like you're right.

Would this be the right way to think about cycle time?
Volume of cylinder = pi * radius squared * height

volume = 3.14 * 2.75^2 * 26 = 617.4 cubic inches
1 cubic inch = 0.00432900433 gallons

617.4 * .00432900433 = 2.67 gallons

16 gpm pump @ 1600 rpm = 8 gpm

2.67/8 = .334
.334 minutes = 20 seconds

so complete cycle = 40 seconds

I'm honestly a complete newb when it comes to log splitters but I'm interested in learning. Any tips on how to check out open relief in the control valve or the open bypass in the pump?

Thanks so much guys. I'm learning a lot here and appreciate your help.

Looks like from the attached picture that there are a lot of pieces in the cylinder that takes up volume even when the piston rod is fully extended.

Dropped height down from 26 inches to 20 inches...
474.925 cubic inches

474.925 * .00432900433 = 2.055 gallons
2.055/8 = .2568 minutes = 15.4 seconds

30.8 seconds cycle time

 

[Oliver1655]

The most economical way to shorten you cycle time is to buy a 4 or 4.5" cylinder to replace the 6" one you have. Before you say "NO WAY!" This is my splitter which has a 4" tie rod cylinder, 16 gpm pump, valve pressure relief set to 2500 psi, & it will split up to 24" diameter by 16 - 24" long rounds all day long. - Cycle time < 9 sec, ~15.7 ton (I have split larger rounds, but rather than wrestle them around on my own, I tend to noodle the larger ones in half.) For really gnarly wood, the 4 way comes off leaving me with an 8" high wedge.



If you have any doubts, it was used all day at the Nixa, MO charity cut a couple of weeks ago so there are several AS members who can bear witness. :msp_thumbup:

 

[darren_nh]

I agree!

The most economical way to shorten you cycle time is to buy a 4 or 4.5" cylinder to replace the 6" one you have. Before you say "NO WAY!" This is my splitter which has a 4" tie rod cylinder, 16 gpm pump, valve pressure relief set to 2500 psi, & it will split up to 24" diameter by 16 - 24" long rounds all day long. - Cycle time < 9 sec, ~15.7 ton (I have split larger rounds, but rather than wrestle them around on my own, I tend to noodle the larger ones in half.) For really gnarly wood, the 4 way comes off leaving me with an 8" high wedge.

View attachment 316439View attachment 316440

If you have any doubts, it was used all day at the Nixa, MO charity cut a couple of weeks ago so there are several AS members who can bear witness. :msp_thumbup:

This is the way to go. Spend a little on a new cylinder ($200) to reduce the cycle time. I have a heavily modified Northstar "22 ton" that is at least 15 years old. I upgraded the 11gpm to 16gpm and added an 8hp gx honda with a 4" cylinder. My results are a full cycle in under 10 secs. Also, this set up has enough power to push just about anything through a four-way wedge.

 

[Wood Doctor]

Splitter Cycle Times

Take a look at this:

 

[rich5556]

Take a look at this:

I'm beginning to think there is something else that's the problem...after replacing the controller, my cycle time dropped from 2 minutes 2 seconds to about 1 minute 15 seconds. Even with the 6" bore, it still doesn't make sense right?

 

[Wood Doctor]

I'm beginning to think there is something else that's the problem...after replacing the controller, my cycle time dropped from 2 minutes 2 seconds to about 1 minute 15 seconds. Even with the 6" bore, it still doesn't make sense right?

No, it does not. I wager that you have to be either leaking hydraulic or picking up air from bad seals somewhere. Such lethargy is unheard of from a properly operating splitter. It's as if you are operating with a toy pump. Or, you should be hearing air leakage somewhere, like a tire losing air. I also would like to hear other members chime in here to help you. This is a bear cat. opcorn:

 

[triptester]

If the cylinder is a used one the seals could be bad causing a lot of internal leakage.

 

[muddstopper]

To get full speed, the engine must be turning 3600rpms. Are you splitting with the engine rev'ed all the way up.

What size hoses are between the control valve and the cylinder. To get max flow you need at least 3/4 hose's. Yea you can flow 16gpm thru a 1/2 hose, but you will not see the benefits of the high flow on the return stroke running small hoses. Your pumping 16 gpm into the rod side for return, but you will have a lot more flowing out of the piston end of that cylinder, 1/2inch hose just slows you down.

Also what is the flow rate on your control valve, if you dont have a 25gpm rated valve, wont do you much good to increase hose size, it will still be restricted at the control valve. You might be able to plumb in a dump valve on the return of the cylinder that lets the oil bypass the control valve and go directly to tank.

To get any real speed out of your cylinder, you probably need a bigger pump, my 5in bore, with 28gpm pump has a cycle time of 12sec. Mute point if your control valve wont handle the flow you already have.

Cheapest fix, besides taking it back where you bought it, would be to downsize cylinder as had already been suggested. I used to split everything with a 4in cylinder and 14gpm pump. I had a 4way adjustable wedge, with a 24in tall blade. Only stuck it once and that was on a 30in dia piece of green white oak that had 4 large knots in it, reversed the round and it split right thru it, 4ways. I have split close to a full cord in about 15min, and worked the ####ens out of 5 people with that setup. I only went with a 5in cyl because I now split 6 ways, with plans for a 10way wedge.