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gas powered air compressor

16035 Views 27 Replies 14 Participants Last post by  biscuit
it's funny. the other day i was thinking i would like to build a gas powered air compressor. i figured i could use any electric one with a belt. and low and behold i found one on the side of the road. i figured the elec motor was bad. i brought it home, plugged it in and it works fine. went thru about 4 cycles of filling it with air and using a blow gun to empty it. it's a sears/craftsman 1hp. but i already have an elec one. so i am gonna sacrifice this one to build a gas one. now the search is on for a sideshaft engine. does anyone have any suggestions on what equipment i might find that has one? i live in the northeast. so we have all kinds of equipment kicking around at times.
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Snowblower,tiller,or edger will have a horizontal shaft engine,that will work as long as its 2,5 hp or greater,a 5-8 hp is aware you'll have to re-place the valve that allows the compressor to shut off once it gets to maximum pressure to one that allows the gas engine to "free wheel" instead,and bleeds off compressor head pressure to allow the engine to be started with pressure still in the tank..a "Load Genie" is one such valve,sold by W.W.Grainger ,part #5x709 is one that will work,costs about 40-50 bucks..
I dont know what they cost today,but my 1995 catalog lists the smaller valve like he'd need at $36.95...that'll handle 20 CFM....the BIG one I'd have needed to make my 7.5 HP 3 phase compressor gas powered with a 25 HP Onan,would need the larger one,rated at 125 CFM,that costed $151.50 back then...I bolted the electric motor back on and sold it after seeing the cost!..

Unless you find a blown up gas powered one in a scrapyard you can scrounge the valving off of,I think your better off leaving it electric..I have a 2 cylinder Bendix compressor off a Mack truck engine that ran the air brakes,it has a valve like the one we're talking about..the only reason I am not already using it is the fact the compressor used tp bolt right to the Mack's engine and had pressure fed bearings that were tapped into the oil pump on the truck--so to use it I'd need to invent a base,and some way to pump oil to the bearings..maybe the valve off a compressor like that could be adapted,I'm not much of an expert on plumbing them up though..

I had the Onan on my compressor,it labored a great deal to pump it up to 125 psi,and once it did and the safety pop off opened,it would wind up to 3,000 rpms,then it would just about stall once the pressure fell and it started pumping again..and if I shut it off with any pressure in the tank,even with a check valve between the pump and tank,the starter couldn't turn the engine over,too much plumb it up right would cost 300+ bucks and I didn't need it THAT bad!...
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Why not combine both and have the worlds first snowblower/air compressor that's gas powered,self propelled and completely portable!..then your buddy cant whine about you "wrecking" two perfectly good machines!..

Dont you love it when someone says things like that??..

I get that a lot.."wyd'ya wreck that,it was a nice (whatever) encouraging,aren't they??..
I tell them I got the "donors" free,saved them from a crusher or dump,and why NOT make something else from them,especially if they are "non repairable" to be used as originally intended!..

I once got a mini-bike frame given to me,no motor or wheels,just the "bones" was someones home built "chopper" they gave up on,the front fork was raked too much and you couldn't steer it,cool as it looked,it was a POS and couldn't be ridden,after I got it all assembled and running with parts and an engine I had hanging I decided to carve it up,and make a trike out of it instead..

Just after I'd cut in up with a saws-all,my friend pulls in and says AWW,man..WHY did you do THAT??..that thing was COOL!..why did you WRECK it??..

I told him it sucked,you couldn't drive the stupid thing,so I wanted to make it into a 3 wheeler..and he said "You must be whacked,you coulda sold that thing for 150 bucks I bet,easily"..I said no one I showed it too made an offer over 50 bucks,and I felt the 6 HP engine on it was worth that alone..and it was MINE to do as I pleased with shaddupp!..:D

After a few weeks of tinkering, I assembled the remains into a 3 wheeled trike,using an old craftsman sit down riding mower's rear half of the chassis, chain drive rear axle and its 5 speed tranny,and the mni-bike's front fork and partial frame..welded it all together,now I had a 5 speed with reverse
3 wheeler, I could go 35 mph with in 5th gear,and use 1st gear to climb steep hills at 10 mph wide open..I used the centrifical clutch, and used a jack shaft to speed up the input to the tranny, so it would not crawl like a tractor in all 5 speeds...

I drove it around most of the summer,then someone driving by offered me 200 bucks for it,and I reluctantly sold it to them..been wanting to build another one ever all the parts too,just aint enough hours in a day..
My "friend" was impressed with the 3 wheeler,and couldn't belive I sold it for that much..(he offered me 100 bucks for it after he rode it the first time,but I wouldn't sell it to him! way of saying "bite me" for saying I "wrecked" what I made it out of!..)
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Most air compressors can be plumbed up in such a manner that when the pressure reaches the maximum desired setting,a valve sends some of the compressed air to the
intake valve on the pump and holds it open,allowing the pump tp "frewheel" without producing any pressure,until enough pressure drop occours and the valve closes and allows the pump to "pump" again by letting the intake valve work normally..

I have seen the old car A/C compressors (the "log" style ones,or York & Tecumseh 2 cyl ones),converted to air compressors by using a gas engine to power them,but you'll need a battery & charging system to get power to engauge the 12V clutch to engauge..we had a truck at the junkyard we put a 4 cyl air pump on its 390 Ford engine we got from a compressor that someone scrapped after the tank rotted thru..used all the original plumbing but it had no valving to shut down the air pump when it reached its maximum--we just let it run with the safety blow off valve open--it wasn't too often it "popped" off anyway,with two of us using air impact guns or sandblasting with had a manual idler "clutch" you had to engauge to tighten the belt under the hood to operate the pump..was very crude,but it worked good...
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