converting a old air compressor

[muddstopper]

If you use the pressure switch that is already on the electric compressor, and wire it 12v instead of 110, then you could use a electric mower clutch on your gas engine. Nothing to it. The big problem would be to get the hp and gear ratio correct. Most mowers use a straight shaft, not tapered so finding a horizonal engine should be easy enough. Now the kicker is that the engine is going to continue to run, even when the clutch is not engaged and making air. Probably not a big problem since you would most likely just be using the compressor for a few minutes at a time.

 

[farmall 55a case]

Well here it is should work for what I want it for. I used a old tiller motor that is a 6.5 Briggs, found a twin cylinder pump at a yard sale and ordered a IR pressure kick down bull whip, and mounted it all up! Hardest part was getting it to idle down and rev to the max rpm. It builds up to 120 psi pretty quickly. It will come in handy for fixing flat tires and blowing of balers! No more running back to the shop!! Of course I had to put my farms name on it and a IH logo! All in all I have about 200 dollars in it.

 

[PILOON]

Here is a KISS method for the unloader problem.
It works because I did it with a rig that I set up that was electric.
I placed a check valve between the compressor and the cut off switch.
That way the tank is always under pressure even with no pressure back to the compressor.
Next I caused a slow leak between the check valve and compressor. It was a very tiny hole, just enough to bleed off the remaining pressure but not large enough to slow down the tank fill.*
With a gas engine it would need to run all the time and a pressure switch could be rewired (needing voltage) to control an electric clutch much as they commonly sell for go carts.
If the engine used is of sufficient HP they generally have 12 volt outputs so there is the electrics for the clutch.

*even a loose fitting will prove that method.

Go cart clutches (they fit straight shafts and available in many sizes)

 

[jwmorris]

The go kart clutches I have seen all work from centrifugal force, like a chainsaw.

Any car with an AC compressor on it would have an electric clutch though.

All compressors have check valves in between the compressor and tank. On electric ones they are so there is no head pressure on the compressor to have to over come when it kicks back on (the hissing sound you hear when the compressor shuts off is the bleeding of the line).

On gas compressors they are there to not stall the engine at idle and let compressed air bypas the tank until internal pressure falls enough to throttle up the engine and shutoff the bypass.