I'm building a splitter. Ive got a 8 HP engine that will be used. I also have access to a free 5" x 30" (new) cylinder. 4"x24" is most popular but a new one runs about $300. Anyone know what GPM 2 stage pump will deliver a reasonable cycle time?
DIY splitter
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brenndatomu
Minister of Fire
8hp will pull a 16gpm pump at full pressure...a 5x30 cyl will have a 18 second round trip with that pump.
You might could pull a 19gpm pump if you reduce the relief pressure a lil bit...that takes the full cycle time down to just under 15 seconds...but both those times assume you let it go full stroke.
A 5" cyl is WAY overkill IMO...
You might could pull a 19gpm pump if you reduce the relief pressure a lil bit...that takes the full cycle time down to just under 15 seconds...but both those times assume you let it go full stroke.
A 5" cyl is WAY overkill IMO...
brenndatomu
Minister of Fire
Well, the general rule of thumb is to have double the gpm of the pump...but only the best of the commercial grade splitters actually have that...most big box/farm store splitters have about half of their gpm and seem to do ok for most people...the main thing is to not let the oil get much over 140* for too long...that quickly reduces the oil life.
brenndatomu
Minister of Fire
No problem...here is a good place to learn and experiment with their calculators. https://logsplitterplans.com/calculators/hydraulic-cycle-calculator.htm
That 8 HP engine with a 16 GPM two stage pump on a five inch cylinder is going to be slow. I find my 28 GPM two stage pump on my four inch is a little slow at times. I run a 25 gallon reservoir on it and split in the summer with no issues.
brenndatomu
Minister of Fire
If that cylinder has a 1.75" rod, and a 24" stroke, a 28gpm pump should put you in the 5 second range, full cycle...2.8 seconds out, 2.3 back!
That's slow!?
If you have 1/2" ports and hoses, then it won't be quite that fast...too much line restriction...
JRHAWK9
Minister of Fire
When I was out splitting last weekend I was trying to pay close attention to the pressure gauge during splitting. I have a 5 1/8" cylinder. Even when shearing the wood through gnarly pieces, I'm seeing under 300psi on the gauge. I have yet to even see close to 500psi. Crazy. So, yeah, a large cylinder is nice if you want to maintain very low system pressures, but it's definitely way overkill. LOL
If fast cycle times are desired, consider a dump valve on the return port. The more GPM the better for cycle time on the power stroke.
The harder and especially faster a cylinder is worked, the more oil capacity is desirable. You can never have to much. It'll help the cylinder run cooler.
The harder and especially faster a cylinder is worked, the more oil capacity is desirable. You can never have to much. It'll help the cylinder run cooler.
I like my 5 inch cylinder. Just saying. The percent of rounds needing full stroke is small. I deal with a lot of VERY large rounds. The ability to know when I pull the lever and something is going to crack in half beats out the reduction in cycle time.
brenndatomu
Minister of Fire
I get a lot of the same kind of stuff, and they generally pop easily with a partial stroke using a 4" cylinder too...although that big crotch round in the pic there might take a lil strategic splitting...
JRHAWK9
Minister of Fire
My 40T splitter with the 5"+ cylinder is somewhat quick for a hydraulic (9.5 sec). It's the only reason I ended up with it. Being a 40T is just a "bonus"........although I'll never need anywhere near the 40 tons. I installed a pressure gauge on it when I first got it and confirmed it does put out the full 40 tons, or very close to it. I have since backed off the relief to ~3,200psi, so it's now ~33 ton. The pump has never shifted from high flow/low pressure to low flow/high pressure yet.
My older 28 ton Speeco would shift all the time, I think the crossover was set pretty low.
Rod is 2.5" and I welded in 3/4" ports actually three ports as I run a dump valve. It is quick can't say I have ever timed it. But when you have a guy feeding the splitter and one guy in the trailer stacking then yes sometimes it seems a little slow. Then I work on some ones TSC special with a 4 inch cylinder , 5-6 HP engine and a 11 GPM two stage pump and then I see what slow really is. LOL
If that cylinder has a 1.75" rod, and a 24" stroke, a 28gpm pump should put you in the 5 second range, full cycle...2.8 seconds out, 2.3 back!
That's slow!?
If you have 1/2" ports and hoses, then it won't be quite that fast...too much line restriction...
JRHAWK9
Minister of Fire
yeah, that's one quick hydraulic with a 2.5" rod on a 4" cylinder with a 28GPM pump!
brenndatomu
Minister of Fire
So that calculates out to a theoretical 4.5 seconds full stroke round trip, plus whatever time the dump valve knocks off!
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