Build compressor from v8 engine

by Todd
(Iowa)

I would like to convert an old Chevy 305 I have laying around into an air compressor. The theory seems solid and I've seen many compressors that run 4 cylinders on gas and 4 to pump air. I would like to run all 8 cylinders to pump air and utilize an electric motor to spin the "compressor".


Anyone had any experience with something like this or any ideas about the best way to do it.

I am thinking about removing the camshaft and modifying the intake and heads to incorporate reed valves.

Any and all help about materials and sizing greatly appreciated

Comments for Build compressor from v8 engine

Click here to add your own comments

Jan 08, 2018
V8 compressor
by: Doug in s.d.ca.

Todd, that sounds feasible.

The engine has what - at least a 10:1 compression ratio, so the air can be compressed to 145PSI minimum - if the motor can push it that hard.

You might want to just open up the cylinders and see how the motor works just turning it with no load before you do much else. I think I would.
And then, maybe close it back up to see if it can push it with the valve holding back - a la starter operation, with no fuel or spark. If it can, then you'll have no problems, for sure.

Keep us posted - sounds fun...




Jan 08, 2018
V8 compressor
by: Todd

I'm hoping to make 120psi. Should be doable since I think if the rings and cylinders are in good shape it should compression check well over that.

I was kind of thinking I would spin it with a 15hp 3,600RPM electric motor speed reduced through sheaves to around 1,000-1,500RPM.

Air receiver would be a 500gal used propane tank.

Might have to play around with the reed valve thickness. Will use 1095 spring steel. I have seen reeds in a IR compressor that were .010 thick, however I might start with something slightly thicker since I will need to cover much larger ports on the intake and exhaust of the old engine.

Let me know if you think I'm way out to lunch on my "math"

Jan 04, 2018
V8 compressor
by: Doug in s.d.ca.

I forgot to mention that the Smith 100 uses a Ford 302, so it should be comparable.

Jan 04, 2018
V8 compressor
by: Doug in s.d.ca.

I haven't done much math on this, but I'm fairly certain it'll take at least a couple of HP just to turn the engine, nevermind making any pressure.

Aside from that, what pressure are you thinking?
You're gonna have have 4 pistons in a compression/exhaust cycle each rev, so the design is more conducive to a high volume, low pressure compressor, I think.

I'm pretty sure that's why the Smith 100, which is rated 100 CFM at 100 PSI max at 2000 RPM, uses half the engine, or around 150 HP, to drive the other bank.

So, it's gonna be tricky...

Click here to add your own comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Ask A Compressor Question.