crazy idea, home-made air compressor?

[don4331]

Couple items of note:

Welding up your own air tanks is high risk - if it fails, it is a bomb.

Simpler solution is to use propane cylinders. Pull the propane paraphernalia out, mount them upside down so no moisture accumulates and you have easy/low cost storage solution. Air coming out has...interesting...smell from the chemical they use to make leaking propane noticeable (And its been >35 years since we hung them). 100lb cylinders = 24 gals.

V-6 engine/compressor would be more challenging than what we did as the cam operates valve on both banks.

We have a Dodge slant 6 connected our compressor, which is a Chev Iron Duke. The cam gears in the 4 banger were replaced with a 1:1 drive, the exhaust drive train removed. As has been suggested, the spark plugs have been replaced with one way check valves piped into the air lines. A truck air brake valve prevents over pressure.

Clutch on the slant 6 engine allows starting the Dodge without the load of the compressor.

Even at idle, it compresses air at an impressive rate; little noisier than electric system though.

 

[adsm08]

Yes, that would work but you would have to have the two valves on the spark plug hole or there would be no "air" in the cylinder on exhaust stroke.

Intake valve only opens on the one Intake stroke sucking air in, then pushes air out spark plug hole on compression stroke
If air couldn't get back in on Power Stroke then there would be no pressure to push out on exhaust stroke.

And with the two valves on the spark plug hole you could disable both cylinder valves intake and exhaust, lol

Right, good point. Better to do a check valve and have cam custom ground to open both valves at the same time on the cylinders being used for pressurized air.

 

[Curious Hound]

I thought the idea would be to use a V8 and have 4 cylinders operate as an engine and 4 as a compressor. Need some safety to prevent fuel/air mix from being ingested in the compressor cylinders.

This message composed solely of recycled electrons. Go green!

 

[pjtoledo]

You would need a good check valve though if using a tank, or else you will end up pulling your air back into the cylinder each time a piston goes down.

I thought about that. also separating the intake runners so the MAF sensor only measures the air that powers the engine.

 

[pjtoledo]

Couple items of note:

Welding up your own air tanks is high risk - if it fails, it is a bomb.


.

I'm not that crazy yet, give me a few months and I'll see what I can do.


many years ago when I was an apparatus service technician I spent some time in the DeVillbis factory. I have seen tanks being welded and tested.


about that "bomb" scenario,,, out in the garage I have an 80 gallon tank that was manufactured in 1945. I'm hard of hearing so I don't know if it's ticking or not.

 

[pjtoledo]

I thought the idea would be to use a V8 and have 4 cylinders operate as an engine and 4 as a compressor. Need some safety to prevent fuel/air mix from being ingested in the compressor cylinders.

This message composed solely of recycled electrons. Go green!

an afterburner in a sandblaster,,,should be real efficient at blowing paint off

 

[pjtoledo]

you guys have some great ideas, how's this one:

for the compressor cylinders, remove the rockers so valves stay closed all the time.
attach a T to the spark plug hole. opposite facing check valves on each side of the T. piston goes down left T opens for intake, piston goes up right T opens to tank. I can see where this would work better on an old engine with the big 13/16" spark plugs. most likely very restrictive with 16mm plugs.

I have 2 different 3.0 engines, an 87 and a 99, each with PCM and wiring.
it's hard to even give a 3.0 away, may as well have some fun with 'em.
the roller cam in the 99 should be easy to weld on??? add lobes, eliminate overlap, add check valve on exhaust only, separate the manifolds.

what could possibly go wrong?

 

[Shran]

There were, maybe still are, companies around that built exactly what you're wanting from factory engines. The one I saw recently was mounted on a trailer and built around a Ford 302 - the distributor was modified and the passenger side bank of cylinders ran on gas and the driver's side was the compressor. I believe it may have even had something other than a factory cylinder head on that side but I may be wrong about that.

I'd like to see gwaii's setup - I seem to remember reading about him using a huge propane tank for air supply.

I sure would like to build something like this but realistically I do have a 60 gallon 220v compressor already... so...

 

[scotts90ranger]

I have one of those 302 air compressors in my driveway, it's set up to run on propane with an air governor that adjusts the throttle based on air pressure... I don't remember what it is either 75 or 100cfm at 90psi, I know the 302 was one and the 460 was the other (but could have been 100cfm and 150cfm).

Anyway, one cylinder head is replaced with a reed valve assembly which has it's own intake and exhaust and blocks off the intake ports in the stock intake manifold, the distributor simply has 4 spark plug wires spliced together in a ring terminal and grounded, could do the same with a V6.

We recently worked on a project at work that did this with an 8L engine compressing natural gas to 3600psi, they made the compressor side a 4 stage compressor with all sorts of fancy check valves and solenoids. I was just in charge of getting the engine to run on and certified on CNG fuel, the engine made about 40% of the power as it would as a V8 due to the pumping losses. In all honesty, it really surprised us how smooth the setup runs...

I haven't ran the 302 compressor that I have, just couldn't pass it up for $50... it'll be used on my brothers farm eventually on a trailer to blow off the combine and so forth...

 

[alwaysFlOoReD]

That is what gets me going is the huge cfm numbers. I could really get a lot of blasting done with that.

 

[don4331]

you guys have some great ideas, how's this one:

for the compressor cylinders, remove the rockers so valves stay closed all the time.
attach a T to the spark plug hole. opposite facing check valves on each side of the T. piston goes down left T opens for intake, piston goes up right T opens to tank. I can see where this would work better on an old engine with the big 13/16" spark plugs. most likely very restrictive with 16mm plugs.

I have 2 different 3.0 engines, an 87 and a 99, each with PCM and wiring.
it's hard to even give a 3.0 away, may as well have some fun with 'em.
the roller cam in the 99 should be easy to weld on??? add lobes, eliminate overlap, add check valve on exhaust only, separate the manifolds.

what could possibly go wrong?

Even 13/16" spark plugs would be restrictive - remember, the exhaust valve is 36mm (1.4") and intakes were larger...

As you have both 2.9 and 3.0; use them together like my old man's shop. Change the cam sprocket on the 3.0 to be same size as crank and you have a 2 cycle. Disable the exhaust valve and put check valves in the spark plugs.

With the 2.9 driving the 3.0, you would get lots of air.

We looked at a large propane cylinder what it sound like Gwaii's set up uses but it was simpler to just use the smaller tanks. (Saskatchewan did rural natural gas project and all the farm replaced their propane setup in late 80s, so there were lot of cylinder being disposed of).

 

[pjtoledo]

Even 13/16" spark plugs would be restrictive - remember, the exhaust valve is 36mm (1.4") and intakes were larger...

As you have both 2.9 and 3.0; use them together like my old man's shop. Change the cam sprocket on the 3.0 to be same size as crank and you have a 2 cycle. Disable the exhaust valve and put check valves in the spark plugs.

With the 2.9 driving the 3.0, you would get lots of air.

We looked at a large propane cylinder what it sound like Gwaii's set up uses but it was simpler to just use the smaller tanks. (Saskatchewan did rural natural gas project and all the farm replaced their propane setup in late 80s, so there were lot of cylinder being disposed of).

no, I have 2 3.0L engines. I'll take a guess that you think the 87 engine was from a Ranger, thus should be a 2.9. It's from a Taurus and is indeed a 3.0. the 99 is a Ranger 3.0.