VW aircooled engine = air compressor

[bajacalal]

Yes it's true, with a few simple modifications you can make a VW aircooled engine into a gasoline powered air compressor. One side of the engine provides power, the other pumps the air using the pistons. Yes, it runs on 2 cylinders which is not ideal but you're only spinning the engine to compress air, not move a car. You can get 50-60 CFM which is much more than I would really need.

I've been itching to build one of these for years and I'm slowly accumulating parts (I want this to be free or very cheap).

Dunn-Right makes the kit to build one but I'm thinking of sourcing/making all my parts separately instead of buying the kit. I might pull the lifters on one side, block the pushrod tube holes and replace one cylinder head with aluminum plate, drilled and fitted with one way check valves (2 per cylinder, 1 in 1 out). I might just modify the stock head...

Has anybody here built one of these before?

BTW, I know of a construction company that uses similar compressors built from Ford Windsor V8 engines, one bank provides power, the other side is the compressor.

[Turbinepowered]

Modifying it to use either the 1/3 or the 2/4 pair would probably be better than the 1/2 or 3/4 pairs. You'll get a more balanced running engine that way, at the expense of having to deal with your compressor cylinders on opposite sides now.

[edit] Dude! That company is literally right down the highway from me. 

[drrtybyl]

Use it to fill the carbon fiber air tank in your compressed air-powered bug 

http://www.mdi.lu/english/

[bajacalal]

Thanks but I already thought about using cylinders on opposite sides of the engine. I don't want the increased cost and complexity of doing it that way for a tool that I will use once a month, probably, at the most. For this reason, I don't really care if it runs crappy or only lasts 500 hours before a rebuild.

I've heard about those compressed air vehicles. It just seems like there has to be a better way to achieve a practical, efficient vehicle. Plus it's French engineering which is usually much more complex and weird than it needs to be, though I actually like the French. Ever look under the hood of a Citroen?

Keep in mind that the compression ratio of an air-cooled VW is about 7:1. I'm want the 1300 for simplicity and lower fuel consumption. That means my compressor will only make ~100 PSI with stock cylinder heads. But it should flow a lot of air per minute, on par with expensive 3 phase commercial units. I'm hoping for 150 PSI if I replace the cylinder heads with aluminum plate or otherwise boost the compression.

I forgot to mention this, I plan to run it on propane (LPG). I will convert it from a gasoline carburetor to an Impco propane system. This is to avoid the problems that come with storing gasoline for long periods.