Homemade fire engine

[bcarwell]

I need fire supression for doing burns. $550 for a gas powered pump is a little steep (I figure I need 60-70psi @ maybe 70-100 gpm to feel safe). But I found a belt driven pump without engine (Item 10627) 73psi 7920 gph at Northern Tool for $140 that gets rave reviews, require a 4 - 7 HP @ 3600 rpm.

My question is: can somebody tell me or point me somewhere that shows how you would homebrew connect a garden variety Briggs or Tecumseh to it ? I obviously need some sort of base platform to mount the engine and pump on. And what about clutching and belt tensioning/pulley, etc. ? Seems I could buy alot of stuff for the $550 - $140 = $310 if I already have a spare engine.

Thanks in advance for any suggestions on kludging this together. BTW I have a welder.
What else do I need ?

Bob

 

[studor]

I have two methods of "fire suppression" you might consider. One is a 3"semi trash pump that I think I paid $169 for on a clearout. I have about 20' of suction hose and since a river runs through the middle of my place I can use it a lot of places. It is powered by a 6.5 hp gas engine that is just straight coupled to the pump -- you just make sure there is water in the pump before you start it. In spots on the property where the pump is impractical I use a pto powered pump to fill 45 gallon plastic barrels, then use the tractor to take them to where I will be burning and use the pump to spray the water as required.
Course the absolute best method I have found is to wait until mid winter with three feet of snow, get out the propane roofing torch and fire it up then -- never had one get away from me in those conditions

 

[Iplayfarmer]

I need fire supression for doing burns. $550 for a gas powered pump is a little steep (I figure I need 60-70psi @ maybe 70-100 gpm to feel safe). But I found a belt driven pump without engine (Item 10627) 73psi 7920 gph at Northern Tool for $140 that gets rave reviews, require a 4 - 7 HP @ 3600 rpm.

My question is: can somebody tell me or point me somewhere that shows how you would homebrew connect a garden variety Briggs or Tecumseh to it ? I obviously need some sort of base platform to mount the engine and pump on. And what about clutching and belt tensioning/pulley, etc. ? Seems I could buy alot of stuff for the $550 - $140 = $310 if I already have a spare engine.

Thanks in advance for any suggestions on kludging this together. BTW I have a welder.
What else do I need ?

Bob

I'm sure there are a ton of ways to do this, but the cheapest way (I think) would be to use pulley's and a belt. Be sure to line up your pulleys with each other or your belts will wear pretty fast. You should be able to get whatever you need for pulleys at your local ACE or True Value hardware store.

For the tensioning, cut slots for your engine mounts rather than holes. Tension your belt by sliding the engine along the slots and then tighten down the mounting bolts. You'll have to do like Studor said and be sure there's no water in the pump when you start it.

 

[bcarwell]

Thanks for the replies guys. I didn't consider a trash pump because I didn't think it would get the pressure (60psi) needed to spray a decent volume of water an adequate distance.

If I straight couple pump and engine does a garden variety 6hp gas motor develop 3600 rpm or thereabouts (what the pump requires for rated output) without any gearing ? I'm clueless about what shaft rpms are for small engines. And would I be able to turn over the engine by hand to start it when its connected directly to the pump and thus loaded (e.g. without any "neutral" for starting) ? I know I can start my pressure washer but that's a much smaller pump and even then when its hard to pull the start rope the manual says to pull the trigger on the sprayer to relieve pump pressure and then pull. Sure enough it makes a BIG difference in the amount of force required to pull the starter when there's pressure in the pump.

I have a PTO pump I'd considered using but like a trash pump I didn't think it had the necessary volume delivery (e.g. 70 - 100 gpm) but like the trash pumps was lower volume and pressure.

Does anybody make a PTO - to pulley attachment so I could run off my PTO ?

And I gather you are supposed to make sure there IS water in the pump before starting up, correct ? (I understood that running such water pumps with air in them is hard on the pump and it may not prime.

Thanks again for any information regarding the above...

 

[Travelover]

................. You should be able to get whatever you need for pulleys at your local ACE or True Value hardware store.
.........................

I agree, I'd hook it up direct drive, but I'd advise getting better quality belts and pulleys at an auto parts store or outdoor equipment store. Those fractional horsepower V belts and aluminum pulleys don't last long with a gas engine.

 

[studor]

I went and read the specs on my 6.5 hp -- 3500 rpm @full throttle, 1400 @idle -- probably pretty common. I thought the semi trash would not deliver enough to use in a fire situation but when reduced from 3" down to 1.5" it seems to work fine with a fire nozzle. If I am burning grass I usually bush hog a fire break and dampen it before I start and find the pump very adequate to contain it. If your engine is a side shaft, I would just direct couple it to the pump and forget about pulleys,belts etc. It will start by hand with just the pump to pull over -- the pump really does not need much to turn over torque wise
The PTO pumps don't deliver much volume but usually have good pressure -- mine delivers lots from a garden hose but I don't think it would do much for a fire nozzle. Again when using it I do the firebreak and dampen thing and watch the edges of the fire very carefully.

 

[bobodu]

Whatever you do...check your engine and pump rotation before sinking money into it.

 

[Stimw]

I needed a pump to jet down a water well for my garden. I bought a 6.5hp 2" pump that is rated at 145gpm from Harbor Freight (95977 or 93662) for $199. on sale. It really worked great! I don't know what pressure it is rated at but it will drown you! It will put out a straight 2" stream.
This would be a lot easier as it is complete and self-contained. The engine looks just like a Honda knock-off.

 

[Iplayfarmer]

Whatever you do...check your engine and pump rotation before sinking money into it.

Once again the pulley system can get around rotation issues. Just orient your engine so that the pulley is going the right direction.

Direct coupling is a good option. I know that Surplus Center has some 3 piece type couplers. They're expensive, though, and I saw that the pump in question already has pulleys on it.

You can work up a clutch system to disengage your engine for easy starting. I guess that would also have advantage that you can have the engine on and running before you actually need the pump to be spraying water. All you need is an idler pulley on some kind of arm with a spring to hold tension. Work up a lever on the arm with some kind of latch to hold it in place when disengaging the engine.

 

[bcarwell]

One other possibility: I have a garden variety Sears 2500 psi pressure washer. Only has the flow of a garden hose, not much, but it shoots far and would probably be very good for wetting the circumference around the fire. And since its mobile the water delivery might be adequate to keep down hot spots where needed. I am considering using it out in the pasture for fire burn supression where I just have a 550 gallon tank and no household 24-40 psi water pressure to feed the washer with.

Can I just stick a garden hose from the intake of the washer into the tank or maybe at the bottom where there is at least some pressure from the full tank ? Will it damage the washer that I don't have the household pressure on the intake side ? The instruction manual for the washer says to never run it without water attached which makes sense since it will hurt the pump to run it dry. But it doesn't make it clear whether you have to have <pressurized> water on the intake or will just any old source of water do. Note the tank is level with the pressure washer in the pasture and I'm not drying to draft water from a location lower than the washer.

And if I consider the Harbor Freight trash pump mentioned previously that has 140 gpm delivery with a 2 inch discharge, if I run it with a 1 inch nozzle to get more pressure and distance will that extra backpressure from the smaller nozzle hurt the pump which is probably not designed for much backpressure on the discharge side....

Bob