I have a compressor I purchased before I moved that was electric (220) and don't have enough power in my current garage to use it so I want to convert it to run on a gas engine, I'm figuring like a lawn mower engine or something like it. Anyone have any insight or experience with this conversion and what is needed?

 

a blowoff valve and high idle circuit.
other than that, it is just a matter of matching pulley sizes

 

I'm guessing the high idle circuit would kick the idle down when you get to top pressure....

 

Compressor heads that are designed to be run by a gas engine have unloaders that open the intake valves once the tank is full, at the same time the engine idles down. This prevents them from increasing the pressure in the tank once it's reached the set limit. Some use a centrifugal clutch on the engine to stop a standard compressor head once the engine idles down, but that isn't as common and getting the proper sized pulley for the engine can be a bit of a challenge.
To get the proper sized pulley, you will need to know the pulley size and maximum and minimum operating RPM for your compressor head, and the rated max RPM of the gas engine. This will help you calculate the pulley size for your engine. Do not go over the compressor's max rpm.

 

You can get whats called a "discharge unloader" to control the compressors capacity. When the pilot valve signals the compressor to unload, it opens the discharge line to atmosphere and sends an air signal to the engine slow down device to slow the engine. A check valve keeps the compressed air in the tank and will not allow it to vent out the open discharge line.

When the pressure falls in the tank, the pilot valve closes, the engine speeds up and the discharge line is shunted back to the tank and the tank is pumped up again.

Now, the engine size can be approximated by doubling the horsepower of the electric motor. If you had a 5 horsepower electric motor then you will need at least a 10 horsepower gas engine.

Now you need to know what speed your compressor is turning. Dia. of motor pulley times motor RPM divided by compressor pulley dia will give you the compressor speed. ( d times comp. RPM devided by D where d=small pulley and D=large pulley.

Next you need to find out at what speed your engine will produce 10 horsepower. Using the above formula and changing it around a bit we come up with: D times Comp. RPM divided by eng RPM will give you the pulley size for the engine.

Hope it all makes sense to you. I can provide the parts if you need. I have attached some info you may find useful.

 

Thanks guys, it does get way confusing. What do the parts run for doing this?

 

Control devices should run you less than $75. Sheave & belts around $100.

 

There was a compressor shop on Auburn Blvd. ( I don't remember the name of the place though) in Sacramento California, that new their S$*t. They helped me set up my on-baord on on my Jeep, and I haven't had a lick of trouble with it since they helped me.

 

You'd probably be best off getting a gas-powered wheelbarrow compressor and using your as an extra storage tank inline until you have the power to run it. That or sell it and replace with one that's already set up.
I got a wheelbarrow compressor off Craigslist with a 5.5hp Honda and three cylinder compressor head for $325. Those sort of deals are not that common to come across, but they are out there.

 

IMO easier & cheaper to run wires for a 220v hook up.... ymmv.

 

My garage is about 100 feet from the house and it will cost about $1000.00 to run it. I can buy a gas compressor for that.

 

How is it wired now, just 120v? No breaker box?

 

Its not wired here, I had it hooked up at my old home with 220v......

 

I meant the garage.... However, if you have 120v to the garage, you might be able to fit a 120v motor to the compressor. Reduced performance, but you retain the pressure switch and automatic on-off functions.

 

How big is your compressor? I have an older Sears compressor (30 years old) that is currently wired for 220. A few wires can be switched around under the access plate and have it rewired for 120 volts. Of course it will draw double the amps at 120 than 220 volts. Do you know if yours can be rewired?

Fran