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Log splitter pump size question.....
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Bernoulli
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Hello all!

First, I would like to say how great this forum is. I have spent the last couple hours reading past entries and have learned a lot from it. I found a link to Surplus Center in one of the posts, placed an order, and paid less then half for what I needed!

I recently bought a really old home made log splitter. Its current configuration is a 1965 Kohler 8 hp engine belt driving a Sperry Rand Vickers vane pump (model 2.884.865). It has a Cross detent valve and a 4"x24" Cross cylinder on it.

I am in the process of removing the old Kohler and vane pump and installing a new engine and pump. I have many different size engines laying around to choose from but I am not sure exactly what running a bigger pump would do for me. All the new splitters with this size ram run 5 hp engines with 11 gpm pumps and create 20 to 22 tons of force. I understand that running a bigger pump would not increase the force created, but wouldn't it make the cycle time faster? I have a good running 12 hp electric start Briggs engine that I would love to use for this. It would go with a 16 gpm two stage pump.

The existing reservoir is about 2 gallons. I am sure that, for cooling purposes, reservoir size will need to increase with pump size and I will install a bigger one with the new pump. Any suggestions on size?

Also, there is not a hydraulic fluid filter on the splitter at this time. Should I install one?

Thank you all, in advance, for your time! I am sure some of you get tired of answering simple questions like this, but it really helps us guys that don't have much experience in fluid power. Thanks Again, Jim
 
Posts: 9 | Location: Owenton, KY  | Registered: 09 January 2012Reply With QuoteReport This Post
Pascal
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Posts: 309 | Location: Baltimore | Registered: 25 December 2009Reply With QuoteReport This Post
Pascal
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Force is psi times cylinder area. Cylinder size determines force.
For the wood I split a 4 inch cylinder is quite fine. SPEED is the issue. They are always too slow...


Speed is flow, gpm.
With high flow, and same psi, more hp is required.

With higher flow, you might need larger lines, valve, ports. That might mean you have replaced everything but the frame and cylinder. Is it worth it?

Yes, add a return filter for sure.

Not knowing the bigger picture, but that you have various free engines, I would put about an 8 hp on it, use a two stage 11 gpm pump. The extra hp would allow you to run the unloading pressure fairly high. i.e. it would go to maybe 1000 psi before dropping to the small high pressure/low volume speed. You would gain a bit more speed this way because it would stay on high volume more of the time.

I would use it until I found another one with larger components, ideally with a bad engine. You might get that fairly cheap. Then put one of your bigger engines on the second one and sell the first one. I would be leary of putting too much replacing into an old one, especially if it was homemade.

Also try the gear and wood burning board at www.arboristsite.com You can search there for hours.

kcj
 
Posts: 489 | Location: Minneapolis MN USA | Registered: 02 November 2005Reply With QuoteReport This Post
Bernoulli
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Jim: Thanks for that link, I never figured there was that much to the reservoir!

Kevin J: I totally agree, they ALL go too slow....LOL! I am in the same situation as you, the 20 or so tons that this one creates will split what I need it to split. I would just like to spend less time splitting, that is the reason for the upgrades I am making. The vane pump on it now is being greatly underdriven. The engine has a 2.25 in pulley and the pump has a 7 in pulley. It moves very slow. If I didn't have it tore down, I would measure the time it takes to run a cycle. I can't find any specs on the pump whatsoever, so I am a little scared of direct coupling it to a 3600 rpm engine. And, with the cost of a small two-stage pump being less than 200.00, I figure it would be a time saving, worthwhile upgrade. Thank you for the link to the arborist site, I sure will check it out.

I keep reading that ATF is the fluid that is used in splitters, and that is what I drained out of this one. Why do they use ATF?
 
Posts: 9 | Location: Owenton, KY  | Registered: 09 January 2012Reply With QuoteReport This Post
Pascal
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quote:
Originally posted by Jim E.:
I keep reading that ATF is the fluid that is used in splitters, and that is what I drained out of this one. Why do they use ATF?


Automatic transmission fluid has a higher Viscosity Index than AW hydraulic fluids due to the addition of Viscosity Index improvers.
The higher the Viscosity Index a fluid has, the smaller the variation in viscosity as temperature changes.


someone painted "April Fools" in big black letters on a "Dead End" sign....
 
Posts: 309 | Location: Baltimore | Registered: 25 December 2009Reply With QuoteReport This Post
Bernoulli
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Thanks Jim, that makes sense. Especially with the weather here in KY. Yesterday it was 50 degrees, tomorrow it could be 10 degrees....LOL!
 
Posts: 9 | Location: Owenton, KY  | Registered: 09 January 2012Reply With QuoteReport This Post
Pascal
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yeah, and when it is 10 out and the machine is started and after a bit of running the oil is 150.
ATF was used more often before Multi-Viscosity Hydraulic Oils were on the scene.
 
Posts: 309 | Location: Baltimore | Registered: 25 December 2009Reply With QuoteReport This Post
Bourdon
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Why do you not spend your money on accumulator? The pump is running all the time your ram isn't. A fantastic opportunity to charge. Then when you pull the lever, action will happen. ;-)


It is not untill you realize how little you know about the subject, that you have actually learned anything.
 
Posts: 616 | Location: Singapore | Registered: 05 July 2010Reply With QuoteReport This Post
Bernoulli
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Yes it does Jim. On cold days my son and I will lay our gloved hands on the reservoir of splitter to warm them up. I always thought that was cool how that worked out.
 
Posts: 9 | Location: Owenton, KY  | Registered: 09 January 2012Reply With QuoteReport This Post
Bernoulli
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Smedsgenbo: What is an accumulator? How would adding one make it cycle faster?
 
Posts: 9 | Location: Owenton, KY  | Registered: 09 January 2012Reply With QuoteReport This Post
Pascal
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accumulator:
http://www.hydraulicspneumatic.../Article/True/66530/

this site is a treasure trove:
http://www.hydraulicspneumatic...0/FPE/IndexPage.aspx


someone painted "April Fools" in big black letters on a "Dead End" sign....
 
Posts: 309 | Location: Baltimore | Registered: 25 December 2009Reply With QuoteReport This Post
Pascal
Picture of brettl3
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I totally agree with Jim Rocco, hes right on the money using ATF as a fluid for your splitter. The highest VI index I have been able to find is Super ATF,193..(Unocal) with typical sheardown of about 28%....I do not agree with a well known famous guru on this subject, (using ATF as a hydraulic oil) as I have used the so called multi-vis hydraulic oils with ZDDP added which caused nothing but headaches....(silting,sticktion,etc.. big time) when used as directed....Smiler Brett
 
Posts: 187 | Location: Port Angeles,Wa | Registered: 16 July 2009Reply With QuoteReport This Post
Bernoulli
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Thanks Brett.

Jim Rocco: Thanks for the links. I read the one about the accumulators and I don't think they are right for me.

Taking into thought the comment Kevin made earlier about not knowing the big picture, I will try to explain my situation, maybe it will help all to understand.

I am 38 years old, jack of many trades and master of none. For a living, I drive a truck. I leave home on Monday morning and don't get back home till Friday night, every week. I am married and I have two children a son that is 8 and a daughter that is 7. We live in a 3 bedroom brick ranch that is fairly well insulated and we heat it soley with wood. This was a joint agreement between the wife and I as she likes to be warm and I don't like 300.00 electric bills. We burn about 4 cords of wood a year that I cut myself. Living in the country, I have access to plenty of wood but my time at home to cut is very limited.

I bought this splitter from a friend who no longer used it. I have 200 in this splitter and its very well built and very heavy duty, it also has a brand new cylinder on it. It hadn't been run in a couple years and I was able to get it running by cleaning the carb, however the engine is worn out and smoking pretty good. Its a 1965 Kohler 181 side shaft 8 hp.

I have 6 or 7 other small engines in my shop that all ran well when I pulled them off their original application. I have a 5.5 hp side shaft Honda GX that has very little hours on it that has the 4 bolt holes for direct mounting a pump to. It would be perfect for an 11 gpm pump and that is my backup plan. I also have a 12 hp Briggs, a 16 hp Briggs IC, and an 18 hp Briggs that all ran fine and are just sitting around collecting dust. The splitter in it current configuration is very slow. I would estimate that it takes 30 seconds to complete its 24" stroke, giving it about a 1 minute complete cycle time.

I am having no luck finding information about the pump that is on the splitter now such as the gpm, rpm, and pressure. I thought that it I could speed the splitter up using one of the bigger engines I already have combined with a higher GPM pump. I would love to be at about 8 to 10 seconds full cycle out and back, at 2500 psi, and be able to run it like this for 3 to 4 hours nonstop so that I will actually only have to run the splitter a couple of days in the fall to split my wood for the year. I would very much rather spend my Saturdays with my family than splitting wood.

I have some 1 1/2" galvanized pipe in my shop that I was going to use to plumb my air compressor with. I plan on using some of this inside the I of the main beam, on either side, to make a cooler on the return side. I am not sure of the exact size of the hoses that are on it, but they are much larger than an other I have seen on other splitters. The hose that runs from the pump to the valve is either 3/4" or 1". All of the new ones use 1/2" for this line. I also have a 40 gallon steel tank laying around that could be used as a reservoir. I can get all the ISO 32 oil that I can use free from my companies shop. When I get back home this weekend I will snap a few pics and post them up. I will also reinstall the pump and start her back up and get a actual time on a full cycle so we can get a baseline starting point to measure improvements from.

It was doing the research for this upgrade that lead me here. If it gets too complicated, I will use the Honda motor and a 11 gpm 2 stage pump and make it easy. I am sure that would be massive improvements over how it is set up now.
 
Posts: 9 | Location: Owenton, KY  | Registered: 09 January 2012Reply With QuoteReport This Post
Bernoulli
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When I parked the truck this evening, I did a little math. If I have done it right I think I found the setup that will get close to my goal.

Volume of a cylinder is equal to pie multiplied by radius squared multiplied by the height of the cylinder.

I have a 4"x24" cylinder. The radius of a 4" cylinder is 2", squared would be 4 again so....

V = 3.142x4x24
V = 301.632 cubic inches

1 U.S. Gallon is 231 cubic inches.
301.632/231 = 1.306 gallons to fill the cylinder.

A 22 gpm pump pumps 22 gallons every 60 seconds, or 1 gallon every 2.73 seconds.

2.73 x 1.306 = 3.56 seconds to fill the cylinder provided the pump don't shift into low gear.

A 22 gpm 2-stage pump needs at least 11 hp, so if I couple it to either the 16 or 18 hp engine, I should be able to run the unload pressure fairly high.
 
Posts: 9 | Location: Owenton, KY  | Registered: 09 January 2012Reply With QuoteReport This Post
Bernoulli
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Now, giving that my cylinder has 1/2" ports and the 22 gpm pump has a 1" outlet, even if my valve could handle the flow I can't get it into my cylinder. Not to mention the amount of fluid/reservoir capacity needed to keep it cool.
 
Posts: 9 | Location: Owenton, KY  | Registered: 09 January 2012Reply With QuoteReport This Post
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