18hp 28gpm belt driven pump

[WoodTick007]

I have a horizontal shaft 18hp opposed cylinder B&S gas engine the came off a start-all and would like to use it to drive a two stage 28gpm or 22gpm pump. The engine has a double pulley currently attached to the shaft and I would like to install a double pulley on the pump. I do not know where to locate pulleys for the pump and I would like to have them sized so I can run the 18hp at 1500rpms and end up with the pump running at 3000 RPMs How would I go about measuring the pulleys currently attached to the engine so I can then calculate the size pulley to install on the pump? And, where is the best place to buy the pulley for the pump along with belts?

Thanks for your help and knowledge sharing on this

Greg

 

[WoodTick007]

I really do not want to be running the twin cylinder briggs at 3000 rpms all day long..... the lower RPMs with save wear and tear on the engine and reduce fuel consumption. I have lovejoy couplers on my gx390 honda and 16gpm but very seldom run the engine at higher RPMs. because I need the power, but want the speed of the cycle times. I am looking to get fast cycle times and power with the engine at a lower speed.

 

[brisawyer]

You are gonna have to set it up on a jackshaft with pillow blocks. Most hydraulic pumps are not set up for the side loading from belts. measure the pulley od and get one half the size that will get you close enough to 2x engine rpm for this. You may run short on hp at 1500 rpm with the 28gpm

 

[Phil_Marino]

I really do not want to be running the twin cylinder briggs at 3000 rpms all day long..... the lower RPMs with save wear and tear on the engine and reduce fuel consumption. I have lovejoy couplers on my gx390 honda and 16gpm but very seldom run the engine at higher RPMs. because I need the power, but want the speed of the cycle times. I am looking to get fast cycle times and power with the engine at a lower speed.

There is a reason you get lower fuel consumption at lower engine speed - the engine is producing less power. With the pump running at twice the engine speed, the engine will need to supply twice the torque that the pump needs. It will certainly run and turn the pump, but you may not get as much hydraulic pressure ( and, therefore, ram force) as you would like before the engine stalls.

In other words, there is no free lunch to be had here.

Phil

 

[WoodTick007]

I fully understand that there is "no free lunch" with regards to HP, ENGINE RPM's, Engine Torque, and Displacement..... I have been splitting 30 face cords a year for 20 plus years with my 13hp Honda running at 1500rpms driving a 16gpm barnes two stage pump and have all the torque I need to split "County Trunk Wood" you know the 16-20ft trunks that are anywhere from 2-4ft across and cut to 18 inch rounds. So in the 'real world" i don't think I will run out of power at 1500 rpm and the engine has a govner or device that is designed to keep the engine running at 1500rpms until it runs out of hp and at that point the pump would stall the engine.

 

[kubotakid]

3.

Just for thought,...You are comparing a 13 hp engine,..On a 8hp load,..The 16 gpm pump, only reguires a 8 hp engine,,,, Eric

 

[Phil_Marino]

I fully understand that there is "no free lunch" with regards to HP, ENGINE RPM's, Engine Torque, and Displacement..... I have been splitting 30 face cords a year for 20 plus years with my 13hp Honda running at 1500rpms driving a 16gpm barnes two stage pump and have all the torque I need to split "County Trunk Wood" you know the 16-20 trunks that are anywhere from 2-4ft across and cut to 18 inch rounds. So in the 'real world" i don't think I will run out of power at 1500 rpm and the engine has a govner or device that is designed to keep the engine running at 1500rpms until it runs out of hp and at that point the pump would stall the engine.

Did that splitter have a 2 : 1 pulley system, where the pump was running twice as fast as the engine? I think that is the important issue here, not how fast the engine runs. IF it did have that ratio, and you were happy with it, then you'll probably be happy with 2:1, 18HP, 22 GPM setup. It should give you about the same max pressure.

Another way to think about it is this : if you connect your 18 HP engine 2:1 to a 28 GPM pump, that will give you the same performance ( both flow rate and max pressure) as if you connected it directly to a 56 GPM pump. (regardless of the engine speed). Is that something that you would consider?

Phil

 

[Ambull]

I fully understand that there is "no free lunch" with regards to HP, ENGINE RPM's, Engine Torque, and Displacement..... I have been splitting 30 face cords a year for 20 plus years with my 13hp Honda running at 1500rpms driving a 16gpm barnes two stage pump and have all the torque I need to split "County Trunk Wood" you know the 16-20 trunks that are anywhere from 2-4ft across and cut to 18 inch rounds. So in the 'real world" i don't think I will run out of power at 1500 rpm and the engine has a govner or device that is designed to keep the engine running at 1500rpms until it runs out of hp and at that point the pump would stall the engine.

Interesting philosophy, taking a big motor and slowing it down on a small pump. It is not the way I do things, but hey, to each his own. If you like running slow, why are you doing the new deal with a big motor and a bigger pump? I would second the motion to bag the belts. Belt drive is hard on the bearings, and you may have tensioning issues as well.

Best of luck with your new splitter. Let us know how it turns out.

 

[Ambull]

the lower RPMs with save wear and tear on the engine

Wrong, high RPM's and low torque saves wear and tear on the engine. Lugging the engine is the worst thing for it. Hell, with the numbers you do, the engine will outlive you if properly maintained.

 

[Haywire Haywood]

I have an 18/28 setup on my splitter and it hums along at 3000 rpm all happy, but run the pressure up and it does make it work. I can't see it at half rpm running the pump at full rpm. Better step up to 24hp if you want to do that.

Actually, I think it' a good idea if you had a bigger engine and the pillow block setup to take the side load off the pump. A 24 at 2000 would probably be quieter than an 18 at 3000. You just have to be careful or set the governor so that you don't over rev the pump. They're only rated for 4k.

Another idea would be this. Since the pump is rated at 4k and most small engines run at 3600 (mine is an older model and runs at 3k), get that 24 and do the ratio of pulleys so that it gets the pump closer to it's 4k rating. That would speed things up a little.

Ian

 

[Rookie1]

I really do not want to be running the twin cylinder briggs at 3000 rpms all day long..... the lower RPMs with save wear and tear on the engine and reduce fuel consumption. I have lovejoy couplers on my gx390 honda and 16gpm but very seldom run the engine at higher RPMs. because I need the power, but want the speed of the cycle times. I am looking to get fast cycle times and power with the engine at a lower speed.

When the pump isnt working how much load is on the engine. I would think an engine at full rpm with little or no load wouldnt wear that bad. You have an idea in your head and Im sure youll stick with it no matter what kind of advice we give. That being said I would like to see your idea come to fruition. Pictures of your progress would be appreciated. Im sure we will learn something from this.

 

[triptester]

I have tried belt drive and found that with higher HP belt slippage becomes a problem. Side loading eventually damaged the pump.

For what you want to do I would recommend using sprockets and chain driving a jack-shaft with a coupling to the pump.

 

[jags]

A jack shaft will be a necessary item. The belt tension that will be required to tame that much HP will destroy the pump bearings in no time. They are NOT designed for side load pressure. There really is no other option for most of the 2 stage pumps on the market, that are used in a belt config.

I'm just trying to emphasize a very important point (that was brought up before, but somehow get the feeling that it might have been glossed over).