Question on cylinder size for DIY honda powered splitter

[Northeaster1]

The father-in-law and I are going to build a splitter in the next couple of months. We usually rent one from a friend of his. It may seem small, compared to the talk here, but there is nothing it hasn't been able to split, and the two-stage pump only kicks in if you get into some narly, twisted stuff, or a big knot.

the rental one has a:
- honda 5 hp
- john barnes 2 datge pump (I believe about 11gpm)
- 3.5" cylinder with 1/5" rod, 24" long.

As we already have a 4 hp honday engine we can use, we are planning on just getting the same size pump and cylinder, as the one we have been renting. I realize they say you need 5 - 6hp for an 11gpm pump, but our experience with it says that the 5 hp honda is only running about mid-way (or less) between idle and full throttle, so we figure that the 4hp should be fine, with the engine revving a bit higher.

Any problems with our thinking?

I am sure the cycle time would be faster with a bigger pump, and engine etc but the 4hp is free, and the rental one seems fast enough for us.

We are planning to make it horizontal only (have strong back / weak mind and a wood hauler with lift for the really big stuff) and I like working at waist level, with the side tables.

 

[Jamess67]

I wouldnt go any bigger than a 4x24x2 cylinder. Any more than that with a 11gpm and your looking at long cycle times.

 

[Northeaster1]

Yes, as mentioned I will likely buy the same type / dimensions of cylinder that is on the rental one we have used a few times. It is 3.5 x 24 x 1.5 and seems to split anything we can find. Cycle time on it is acceptable, but like you say, I would not want to go bigger, and slower, unless I went with a bigger pump. (and engine). Where the father-in-law has a honda 4hp just sitting there, and we have been happy with the rental unit's performance, I think this will do us.