Originally Posted by discontinuuity
I just came across this build. I know you're quite far along, but I've heard that some kinds of automotive air conditioning compressors can be adapted into steam engines. You can only use the older piston-type compressors and not the newer wankel-type. But they have the valves already built in.
Thanks for the input.
First of all, let me say the reason people wanting to run steam try to convert air compressors and 2-strokes in the first place is cost. Mike Brown makes some really nice steam engines in the USA, but 1 hp is $1200 and 3 hp is $2400. You can buy a 2 hp steam engine from India for $650, but it's a big clunky industrial thing unsuitable for installation in a bike frame.
In the process of a researching this project I checked out the possibility of converting a compressor to steam. One of the challenges is that there is so much conflicting information as to what is the best way to go. I even half-disassembled a compressor I have to see if I could use it. I gave up on that approach when it became obvious there are real issues with handling spent steam. There is no crankcase on an air compressor as the crank is out in the open. Exhaust comes out the bottom of the cylinder. I would have had to make a crankcase. A 2-stroke works with a bash valve approach similar to what you would use on an air compressor but it has an exhaust port and a crankcase that can be converted as I did mine. Additionally, the air compressor "ring" (actually a plastic cup) is rated only to 175 F, far short of what I need (I'm figuring 300 F), so I would expect premature failure there. The real problem is, I haven't found any information from anyone who goes beyond just experimenting with these converted machines. How well any of them perform long-term is anyone's guess. The big difference with the one I built is the wet crank. I've not seen anyone take that approach. Will it solve the lubrication problems? I don't know, but I'll give it a try. There's a guy trying to sell heads to convert air compressors to steam for $850 - I wonder if he knows you can buy an honest-to-goodness factory made 2hp steam engine for $650?
If I had a lathe, I'd machine my own engine in the size I want, but I'm a backyard mechanic with limited tools.