Has anybody here ever built an air compressor from a 3-cylinder engine?  I've been toying with the idea of taking a geo metro engine, sealing off the exhaust ports and threading pipe into the sparkplug ports.  A series of check valves on the pipes threaded into the plug ports will keep the cylinders isolated from each other and also provide a second intake path for what would normally be the power stroke.

I'm thinking I should be able to drive it from a 1 or 2 horse electric motor and end up with a compressor that can keep up with any air tool I throw at it.  I know a lot of you guys have fairly well outfitted shops so thought I'd ask here to see if anybody has tried anything like this before.

Wow thats pretty sick.

Sounds like a cool idea, but I think you may need a more powerful drive motor.

Sounds like a cool idea, but I think you may need a more powerful drive motor.

Yeah, I'm not 100% sure how well a 1 or 2 horse will work but since I've got a couple of 1-horse motors laying around from a couple of family members replacing leaking swimming pool pumps I thought I'd give it a try.  I've heard of people taking 4-cylinder engines, disabling  fuel and spark to two cylinders and rerouting the exhaust to make a nice self-powering air compressor and the engine chugs along pretty good on the two remaining cylinders.

I'm thinking if maybe I use a belt drive and have some RPM reduction between the electric motor and the converted engine I should be OK. 

If you think about it, the typical starter motor couldn't produce more than a couple of horse power and it's being used to drive the flywheel with a pretty good gear reduction, maybe 10:1 or better.  Even driving the engine at a few hundred RPM's will produce a lot of air flow.  Actually twice what the engine would normally consume during operation because I'd be turning the exhaust stroke into a second compression stroke.

I guess the big question is how much torque is required to turn a single cylinder through a compression stroke.

Keep us updated, with pics if you can. Sounds like a great project.

hook the rear wheels of the tracker up to it...that might have enough torque to run it!

Well, the tracker just decided it's not going to start again.  Still can't find the battery drain.  oh, and I got home from work today to find that my washing machine had decided to self destruct and dump water and oil all over my kitchen....  Guess there goes my tax refund....