Using a multicylinder engine as a compressor

[Screwdriver]

You reallyndon't understand this do you. A compressor is not an engine, you don't need or want a space above the piston - that said I accept your statement about scavenging - to a degree.

I really do and your comment above is effectively agreeing with my observation.

Either put up with the inefficiency or make radical changes to the valve timing or the valves themselves. That is what I said...

It would be a fun project especially if you wanted high cfm and hang the expense. As @hotponyshoes suggests though, there is a law of diminishing returns to any modification and you can either do a quick easy hack for some low efficiency high cfm or bite the bullet and use an actual compressor.

 

[minimutly]

Yep, just buy a site hydrovane...

 

[DAPPH]

or any cheap compressor & fit it to the working engine ...be interesting in a few years when we get scrapped electric vehicles complete with the battery pack to play with .

 

[Farside]

...be interesting in a few years when we get scrapped electric vehicles complete with the battery pack to play with .

They're already being snapped up for old banger conversions.
www.londonelectriccars.com

 

[Ianb]

Sorry if I have missed it and its been mentioned, youtube has quite a few videos of converting engines to work as compressors, some seem to use plates and reed valves in place of the engine original head. There is loads on there, but tend to be Russian/Eastern Europe.

This guy has a lot of interesting videos on how to make cool things, really talented imo.

 

[Screwdriver]

Sorry if I have missed it and its been mentioned, youtube has quite a few videos of converting engines to work as compressors, some seem to use plates and reed valves in place of the engine original head. There is loads on there, but tend to be Russian/Eastern Europe.

I think the premise for this thread is to be able to run half an engine to drive the other half as a compressor.

 

[sako243]

I still think there are easier/better ways of making an engine driven compressor if yoynwant one fitted in a running vehicle.
An aircon pump looks ideal to me. Maybe fit 2 of them (might find a 2nd bracket from a lhd car?) Set one on a high ratio pulley for quick tank fill and the other on a low ratio to build up higher pressure. Switch the existing 12v clutches with a tank pressure switch.

Having got one of these setup on the Land Rover I can say you almost don't need a tank. I haven't tested it but doing a bit of research when I built it I think the little compressor I have is capable of in the region of 8-12cfm. The key point is it's delivering that at pressure not free air!

I had an oiler and trap setup for lubrication but the trap kept shattering (cheap ebay job) so doesn't run with one anymore. Whole thing was lashed together quickly one evening and haven't had a chance to sort it out neatly since. There's a dinky P38 air reservoir tucked up behind the rear wheel.

I've run my plasma cutter off it quite happily and that eats air. In fact at tick over the compressor delivers so much I could hear the engine coming on and off load as it was being used because it was refilling the tank so quickly.