Engine - air compressor conversion?

[Hooked_on_HP]

One thing I haven't seen addresed yet is stopping fuel from going to the cylinders used as the compressor.If you don't you are building a BOMB.
You also have to figure out a govenor set up to control the engine .
If this was an easy conversion engine compressors would be cheap and easy to find.
Bill

 

[zmoz]

One thing I haven't seen addresed yet is stopping fuel from going to the cylinders used as the compressor.If you don't you are building a BOMB.

The intake of many different engines can be easily blocked, allowing another hole somewhere else for air intake. I thought that was obvious...the same as redirecting (part of)the exhaust into the air tank.

The more I research the more I see these are actually quite common in industrial compressors. You just don't notice them because they're inside a beat up old trailer.

 

[smiley]

One thing I haven't seen addresed yet is stopping fuel from going to the cylinders used as the compressor.If you don't you are building a BOMB.
You also have to figure out a govenor set up to control the engine .
If this was an easy conversion engine compressors would be cheap and easy to find.
Bill

If you look back at the photo's of the slant 6 manifolds, it's simply a matter of cutting them off and welding up whatever is needed for the conversion. Not quite as easy on V-8's or 6's with integraly cast manifolds but certainly do-able. Just look at headers and early 6/8 carb or fuel injection setups.

 

[dcyrilc]

I have an old Grimmerschmidt compressor which used the ford V8. They still sell parts for them. Worst case senario, buy an intake and head.

 

[Hooked_on_HP]

The intake of many different engines can be easily blocked, allowing another hole somewhere else for air intake. I thought that was obvious...the same as redirecting (part of)the exhaust into the air tank.

The more I research the more I see these are actually quite common in industrial compressors. You just don't notice them because they're inside a beat up old trailer.

Using a chevy 350 as the op wants to how are you going to block off the intake to prevent fuel from entering and still get air in to compress with out building some exotic intake.
Bill

 

[handirifle]

Using a chevy 350 as the op wants to how are you going to block off the intake to prevent fuel from entering and still get air in to compress with out building some exotic intake.
Bill

I would the KISS method. Why try to cut and weld on an aluminum manifold, unless you're skilled with TIG. I would make a sheet metal "plug" by bending some light guage steel to a shape that would fit about 2 or 3" inside the manifold, from the head side. I would bend it so you have a flat baffel, with tabs bent on 4 sides. I would then place it inside the manifold and drill through the top and bottom of that runner and run a sheet metal screw through each hole, into the baffle.

I'd then remove the baffle, and apply a liberal coating of JB Weld on the outer edges.

Once dried, I would then drill out an opening in the top of the runner, BETWEEN the baffle and the surface that contacts the head. Make it large enough to provide sufficient air flow (3/4" or larger) and thread it with a pipe thread to allow fittings to be attached. If you could, it would be better to totally open it, ie. cut it off from the baffle out. The more air in, the more efficient it will be.

Maybe some else has a better method.

Anothe thought might be that if you're using only one bank of the engine, have the manifold cut with a metal cutting bandsaw, to a straight flat, surface, that cuts off all the compressor side ports. Block them off with sheet steel and JB Weld (there's no pressure coming out the manifold) with the JB on the OUTSIDE of the manifold, and make new adapters to attach to the head and routed to your intake air filter.

 

[smiley]

Using a chevy 350 as the op wants to how are you going to block off the intake to prevent fuel from entering and still get air in to compress with out building some exotic intake.
Bill

Or keep it really simple and buy four of these, ( Spark plug "air compressor")
stick them in the spark plug holes and be done with it. If I remember correctly, they have one way valves that allow intake of air on the downstroke and close on compression out the hose. I have one in the barn and will check it today. Then you can close off the manifold any way you want. Even stuffing rags down it--- until they worked through to the valves--which could make for some interesting noises and air output.

 

[PHILIP8N]

Or keep it really simple and buy four of these, ( Spark plug "air compressor")
stick them in the spark plug holes and be done with it. If I remember correctly, they have one way valves that allow intake of air on the downstroke and close on compression out the hose. I have one in the barn and will check it today. Then you can close off the manifold any way you want. Even stuffing rags down it--- until they worked through to the valves--which could make for some interesting noises and air output.

I believe the 'spark plug' compressor inserts only work on the compression stroke, and will still discharge a combustable mixture. Still uses inlet air from the engine intake valve. Think about the discharge area the compressed air can exit thru the spark plug hole, about the size of a pencil. A 1/2 horsepower compressor will flow more air than that! The old monoblock Grimmer-Schmidt 302 and 351 compressors with dedicated head and two way concentric compressor valves make 125 scfm and 175 scfm. They also had automatic variable speed control to control capacity and automatic unload when discharge pressure was reached. How is you homemade machine going to do this? The death of the monoblock compressor for commercial use was Ford obsoleting the 302 and 351 engines and the necesary EPA requirements a new engine/compressor configuration would have to meet. Electronic controls did not help either since you are now using half an engine. To do it right, investment cost would be huge. Cost of the diesel rotary screw compressor was now near equal to the monoblock compressor, so this is all you see on the markert now. Plus, the diesel rotary screw compressor will have a much longer life than the reciprocating monoblock compressor. Philip.

 

[westcliffe01]

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I believe this is one of the companies who started the conversion of VW engines and they still do them, even turnkey compressors on a trailer.

They drive all the valves with a cam, this is much more efficient than incurring pumping losses when working against spring loaded valves.

 

[Mace Canute]

Regarding the "spark plug air compressor"...the engine piston stroke is used to operate a simple diaphragm by the action of suction & compression. The air that goes into the tire is drawn from atmosphere and the unburnt fuel from the cylinder goes out the exhaust pipe.

The "combustion chamber" size also affects the efficiency of an compressor made from an engine and by quite a bit. That's why commercial compressors have a very small volume above the piston @ TDC. The smaller the better actually.