larger motor on old splitter

woodman52 · January 20, 2021, 01:21:47 PM

I have an older (@30 years old) 25 ton MTD splitter. The motor is getting tired. I am thinking about replacing it with a new larger motor. The splitter now has an 8 HP motor and a 15 gpm pump (based on replacement pump from MTD) I am thinking about putting a 14 HP B&S motor on it with a 22 gpm 2 stage pump and maybe a new valve. I believe it has a 4" cylinder (based on outer diameter of 4.85") I know this should speed things up a bit but does it make sense and what might the issues be? I know the existing tank might be a bit small but I usually only run it for a couple of hours at a time.

mike_belben · January 20, 2021, 01:40:06 PM

The deciding factor will be the displacement of the low flow gearset in the new pump. The 22gpm is no big deal at 900 psi but when you get to 3000psi and are on the low flow high pressure side we need to know 14hp is enough. Because if it aint you either have to back the pressure off or have the engine stall.

sawguy21 · January 20, 2021, 02:06:41 PM

I upgraded a 5hp to 8hp and cranked down the presure relief valve on a Yardman (MTD) the customer wanted a 4 way splitter. Bent the ram which became the weak link.

hedgerow · January 20, 2021, 03:18:15 PM

I have replaced several of those 8HP 16 GPM two stage motor pump combo's with Harbor Freight 13 HP motors and 22GPM two stage splitter pumps and it worked quiet well. Never up sized the hyd tank but most folks aren't splitting on the hottest days of the summer for eight hours a day. The 22 GPM pumps really speeds up the cycle time. Look a Surplus Center Lincoln Ne for the pump, mounting bracket and love joy coupling.

jmur1 · January 20, 2021, 08:14:23 PM

I ran a 15 HP Honda knockoff on a 22 GPM pump for some time and found it to be a good match. Heat was a problem on hot days. Should work well for you if you work now and again. Try to upsize the hose and fittings. This will help to reduce restrictions that will in turn reduce heat. Increasing tank size is a good thing but not necessarily required.

jmur1

petefrom bearswamp · January 21, 2021, 07:03:20 AM

When the Briggs 8hp on my home built splitter died after 25 years, I replaced it with a Honda 5 hp about 15 yrs ago no appreciable difference in either power or speed, less gas too.

woodworker9 · January 21, 2021, 02:08:28 PM

Several commercial grade manufacturers use this combination with great success, but the plumbing is critical. Either a dump valve or check valve is used, and all the hoses are upgraded to a bigger size than what you'd find on your splitter.

My Wolfe Ridge has a GX390 Honda with 22 gpm 2 stage pump, 5" cylinder, 4" ram, and the cycle time is just over 8 seconds. It has a true rating of 35 tons, and there's nothing it won't split. I can run up to a 12 way wedge on it.

Iwawoodwork · January 21, 2021, 04:25:45 PM

What is the cost of the B&S 15HP/ A new 27 ton splitter is not much more . this summer, June or July, I purchased a new 27t at Costco for $788 and have seen similar sale prices posted at other stores since around here.

woodman52 · January 21, 2021, 10:13:22 PM

I will probably end up spending more for a motor and pump than you paid for the new splitter. But the new ones I looked at are not nearly as heavy built as my old one and won't be nearly as fast as what I will end up with. When I looked around I didn't see any in that power range for under $1000 / 1200. And the ones with 22 GPM pumps were well over $2000. I will check again, I would prefer to buy a new one lf I could find one close to what I want for close to the same price.

sawguy21 · January 21, 2021, 10:36:01 PM

@Iwawoodwork I will just about guarantee for that kind of money yours was built overseas with a knockoff engine, pump and non standard hydraulic fittings. If you are happy with it that is great but good luck finding repair parts, it will break.

Al_Smith · January 22, 2021, 10:19:14 AM

I think a lot of that heat deal is related to flow, cylinder size which relates to pressure .But don't forget how much oil the machines carries plus what type of oil .In my case it's some where between 9 and 10 gallons of Dexron 2 auto tranny fluid with a 5 inch cylinder 16 GPM pump pushed by an 11 HP Briggs IC industrial only running about 2/3 throttle .It doesn't run hot and seldom shifts to high pressure lower volume .
My buddy has a TSC with an 8 HP Briggs running at governed speed with a 4" cylinder and 16 GPM and you could fry an egg on that cylinder .It's little faster but at the end of the day the amount of split wood would not be much different .I think his holds 8 gallons ,again Dexron 2 .I know as I replaced the engine on that thing .

Al_Smith · January 22, 2021, 10:25:41 AM

Most people think they need a faster cycle time like it's a hot lap at the Indy 500 going for the pole position .I don't because at 2/3 throttle it will out run me and I don't have listen to that big single cylinder engine trying to blow my ear drums out .Maybe I'd have different view point if I were 25 years old but I'll be 73 in a few weeks plus I'm retired .Hurry up is no longer in my vocabulary . ;D

woodman52 · January 23, 2021, 06:06:21 PM

Quote from: woodworker9 on January 21, 2021, 02:08:28 PMSeveral commercial grade manufacturers use this combination with great success, but the plumbing is critical. Either a dump valve or check valve is used, and all the hoses are upgraded to a bigger size than what you'd find on your splitter.

Can you explain the use of these valves and how I would plumb them. I am not sure I can do much with the hoses as the new pump and valve call for the same size as what is on the machine now and the cylinder is fixed as to the size it uses (1/2"). I assume that would cause me to need a dump valve even more but I don't know about these things. Always interested in learning new things.

hedgerow · January 24, 2021, 10:48:51 AM

Quote from: woodman52 on January 23, 2021, 06:06:21 PM
Can you explain the use of these valves and how I would plumb them. I am not sure I can do much with the hoses as the new pump and valve call for the same size as what is on the machine now and the cylinder is fixed as to the size it uses (1/2"). I assume that would cause me to need a dump valve even more but I don't know about these things. Always interested in learning new things.

I don't think you will need to up size any hoses or valve with a 22 GPM pump. You could install a dump valve on the retract side of the cylinder but I don't think you will need one. I know were a home built is running with a 28 GPM pump on a four inch cylinder with half inch hoses on the cylinder and no dump valve and this guy only splits in the summer and he has had no issues with that set up in close to twenty years. He only got a ten gallon oil tank on it also.

Bricklayer51 · January 25, 2021, 10:23:49 AM

i have almost the same splitter mine is 32 ton had the cylinder rebulit couple years ago when one of the fittings cracked and was leaking works like new at your age why do you want faster this way when you return the ram you got time for a swallow of beer

jmur1 · January 25, 2021, 10:53:51 AM

I can agree with the idea that most of the recommendations here are for small improvements that will only change your speed a just noticeable amount. Most options are only for small cycle time improvements that a high production outfit would prefer.

What pump were you looking at? The industry generally likes to keep hydraulic fluid (under pressure) moving at 20-25 feet/sec. The 22 GPM pump would fire the fluid through a 1/2" ID line at 36 feet/sec. It would send it through a 5/8" ID line at about 23 feet/sec. If you are in this range your pressure lose per foot of 1/2" tube is shooting up over 10psi/foot which will result in more heat and slower speeds.

But for short lines its not a huge impact. Try out the new pump as is - it may be perfect for you. Just keep one eye on the heat because once it starts to climb it will enter damaging territory quickly. Put your hand on the cylinder after a run. If its too hot to hold on there then let it cool or it could cause pump or seal damage.

jmur1

Nathan4104 · January 26, 2021, 09:34:06 AM

Quote from: woodman52 on January 23, 2021, 06:06:21 PM
Quote from: woodworker9 on January 21, 2021, 02:08:28 PMSeveral commercial grade manufacturers use this combination with great success, but the plumbing is critical. Either a dump valve or check valve is used, and all the hoses are upgraded to a bigger size than what you'd find on your splitter.

Can you explain the use of these valves and how I would plumb them. I am not sure I can do much with the hoses as the new pump and valve call for the same size as what is on the machine now and the cylinder is fixed as to the size it uses (1/2"). I assume that would cause me to need a dump valve even more but I don't know about these things. Always interested in learning new things.

to make use of a dump valve (pilot operated check valve) you have it in the cylinder base end line. A 3rd hose from the rod end 'triggers' the check valve to open during retraction. You'd have it plumbed straight back to the tank. Ideally you could use 3/4 hoses. Think taking your cylinder to a machine shop and having a larger port put in. But, you'll see no real advantage with a stock cylinder. Where you'd see a speed/heat difference is if you upsized them rod. Find an online calculator and play with the numbers. Changing the rod size makes it so it takes way less fluid to retract the rod (it's bigger so less room in cylinder for oil) but the base end has lots so it needs to get out as fast as it can, which could be up to 30-60gpm (in theory). The dump valve will direct it all back to the tank, through a bigger hose (less heat, a bit more speed)
however a normal set up is likely running at near the published number of say 15gpm. The return flow could be 25, which most valves are rated for and 1/2" hose will take. So to add the dump valve to a stock system would help with heat by reducing flow through the whole system (possible extra wear on a valve?,)
I went through this with my processor. Had the cylinder rod upsized, 3/4 port put in, dump valve. I sped up the cycle time by a few seconds (return is faster) which in my case allows me to cut and drop the next block into the splitter a few seconds faster per cut. Makes about 5-7 minutes difference on a cord. Worth the $7-800 it cost me? Likely not but was a learning experience and fun.

woodman52 · January 26, 2021, 12:50:18 PM

Quote from: jmur1 on January 25, 2021, 10:53:51 AMWhat pump were you looking at? The industry generally likes to keep hydraulic fluid (under pressure) moving at 20-25 feet/sec. The 22 GPM pump would fire the fluid through a 1/2" ID line at 36 feet/sec. It would send it through a 5/8" ID line at about 23 feet/sec. If you are in this range your pressure lose per foot of 1/2" tube is shooting up over 10psi/foot which will result in more heat and slower speeds.

I was planning on a Haldex pump. The line from the pump to the valve is 3/4" but from the valve to the cylinder is 1/2 or a little less. About 2' of steel line. I figure if need be I could always run the motor a little slower. Easier on the whole system.

jmur1 · January 26, 2021, 01:11:34 PM

I saw this link on another site last night - a handy chart:

Hydraulic Oil Pumps - Required Horsepower

jmur1

doc henderson · January 26, 2021, 01:39:35 PM

@jmur1 thanks for the chart. it illustrates the exponential nature as the flow increases. It does not reflect a 2 stage setup directly, but most of the 2 stage pumps convert to a 3:1 ratio of high flow low pressure and low flow high pressure. so the flow of a 28 gpm 2 stage pump goes to 7 gpm at the high pressure cut off, and the HP at that pressure is right on that chart. a single stage HP requirement would be high. My 28 gpm pump (2 stage), called for a 16 HP engine, and I went with an 18 HP to be sure. If you look on the splitez website, it lists the HP required for each pump.

doc henderson · January 26, 2021, 01:40:58 PM

a 22 or 28 gpm pump may benefit from a dump valve. the smaller pumps, prob. not so much. and with a larger rod size as well.

jmur1 · January 26, 2021, 03:05:06 PM

@doc henderson It surprizes me that the splitez site does not show the high and low GPM. I guess they choose to show the HP instead. You got it - you have to look at both to figure out if your pump wil stall your engine.

I noticed when I reworked my cylinder to a larger ram a big change with the dump valve. I think I will rework my outlet ports on the next one to allow for even more.

jmur1

doc henderson · January 26, 2021, 04:12:26 PM

yes, if I screw my rod up, I will look into that. My plumbing is so neat and tidy, that I hate to redo it. but if I had a 4 inch ram in a 5 inch cylinder, then the dump valve would be very needed with a 28 gpm pump. I would also consider the 2 lever auto valve, now that my son is 19. course he now thinks he knows everything, so maybe not!... :D :D :D. the high and low rates is from memory, but you are right, they do not come right out and say. it is like 2 separate pumps, and the low pressure is shut of at the set pressure.