convert air compressor to IC engine

What you need is a setup where your motor and pump spin continuously, but the pump would actually pump air only when needed (and when the motor comes up to speed).

A Quincy dealer will get you started. You likely need a different unloader, not electric. Quincys use a special pneumatic unloader that may be hard to find except at a Quincy dealer.

Your pump may have the right kind of unloader already, but most likely it does not.

You may be able to find specific controlls for your compressor, but Grainger has unloaders for gas powered compressors. All they do is bypass the discharge to atmosphere.

Check almost any tractor-trailer truck, or air brake, shop. They will know all about it and have the parts.

But, if memory hasn't failed me, the unloader simply unloads the compressor when system pressure reaches the "set" value.

Regards,

J.B.

I believe that Quincy unloaders need a control valve that does the opposite of what this one does. I may very well be mistaken about it, but I went through this when setting up my Quincy compressor.

I had a small Speedaire compresser with a 4 hp Briggs and Stratton engine. It had only a pressure relief valve that was set for 90-100 psi. The engine ran continuously at constant RPM. When the pressure in the tank reached 100 psi, the relief valve would vent and release excess pressure. I imagine that if you were to make up such a setup that you would want to make sure that the relief valve would be properly sized so that the compressor pump could not overtake it.

On Nov 28, 5:11=A0pm, "Greg O" wrote: ...

That's a lot more complex than the Load Genie I've had on my homebrew electric compressor since the late 70's. It has a sliding valve operated by the pressure difference between the head and the tank. Soon after the electric compressor stops the valve slides to seal off the tank and bleed the line to the head. When the motor starts it bleeds air briefly, then slides to close the bleed vent and open up to the tank. Side loading from the plumbing can jam it.

My little Campbell-Hausfeld tankless compressor has an adjustable blow- off calibrated in pressure. It won't start with much back pressure so I have to turn it on before connecting an external storage tank. It's fine for inflating tires out back where I have electricity but not piped air, but very inefficient for prolonged intermittent use with a tank.

You could rig up a temporary equivalent from a water-heater relief valve and separate manual bleed and tank inlet valves.

I watched a gas compressor on a logger's truck recently. It ran at full speed to fill the tank and then dropped to idle and vented the compressor head. After he had drawn the tank down a ways the engine kicked back to full speed. The engine was a Honda. I didn't see a name on the rest of it, which was mounted too high to examine closely.

jsw

When I first read that subject line I envisioned someone adding fuel injection and a spark plug to an air compressor and trying to run it as an IC engine. Yikes!!!

Some clever mechanics in the Air Corps ordnance company my father commanded in the Phillipines did the reverse; they turned a Jeep engine into a refrigeration compressor to make ice for the club. My father contributed by loading his Jeep onto a cargo plane, flying to Manila, loading up a barrel of whiskey and one of brandy at a brewery, then driving & flying back.

From what I've heard and read the Fifth Air Force was a free-for-all from the General on down, though an -extremely- effective one.

jsw

The subject had me thinking of those V8's where 4 cylinders were the engine; the other 4 were the compressor, courtesy of a way different head.

On Sat, 28 Nov 2009 11:29:39 -0600, the infamous "Karl Townsend" scrawled the following:

I'm sure "they" do. You'll need a vacuum solenoid which can kick it into higher revs for pumping, and drop it down to idle when the pressure switch tells it to. And a pulley the right size.

Talked to Grainger or McMaster yet? Or Orchard Supply?

-- Some days, it's not even worth chewing through the restraints.

Ive got several external tanks..and I simply put a decent check valve on each outboard tank

Gunner

"Aren't cats Libertarian? They just want to be left alone. I think our dog is a Democrat, as he is always looking for a handout" Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls. Keyton

How bout having the diesel turn a generator head, to drive the compressor motor ? If the diesel itself is electric start, you could rig it up so that when the pressure switch calls for air, it starts the diesel, so the diesel doesn't have to run all the time.

This is about the worst use of a diesel engine that you can think.

Plus, the starting diesel would have troubles starting the compressor.

I have one small tank set up with a ball valve and male disconnect that will deliver a BIG blast of air to seat a tire bead etc. Otherwise, check valves.

jsw

Why? Then how bout a gas driven generator head?

Keep in mind that almost all diesel locomotives use the diesel to drive a generator, which drives electric traction motors -- thousands of hp worth.

Well, mebbe some kind of timed clutch? Or delayed unloader valve?

Or, since jthe OP was going to leave the direct-drive diesel on all the time, just leave the generator on all the time, and let the compressor kick on/off normally. I was just thinking of ways to save energy/fuel.

Wayback in the 70s, I had a small 2HP electric air compressor that I wanted to convert to gas engine power. This pump was nothing like a Quincy, just a 2-cylinder, single stage pump (reed valves in the head).

The parts were available from Campbell Hausfeld, consisting of 2 pneumatic control valves, and I believe they were referred to as an unloader, and a governor (no connection to the engine throttle). I got a new Techumseh 5HP engine (Small Engine Distributors, in the midwest USA) to replace the 2HP electric.

I don't think the idea was to vent the pump's full displacement air to atmosphere, but it did prevent the tank pressure from increasing until the tank pressure dropped to a point where it needed to be increased. It made a lot of hissing noise out of two small (maybe 1/8" ports), so maybe it was venting the pump air.

A Quincy distributor/parts dealer should be able to provide the correct parts to ensure that the setup is safe and operates efficiently.

An air starter would be good in this application :-)

Mark Rand RTFM

(...)

"There's a hole in the bucket, dear Liza."

--Winston

Far too much conversion loss, and way too RUbe Goldberg. (NOT That there's necessarily anything wrong with that...) You turn gasoline or diesel fuel into rotational energy at a loss (thermal mostly), then convert the rotational energy into electricity at a loss, then the electricty BACK into rotational energy at a loss, just to turn the compresor head.

If you have the engine running, you turn the compressor head direct to the engine and cut out all the other conversion losses - the only reason to be running an electric compressor is when you don't want to run the prime mover yourself, you buy the energy off the grid.

The smart way is to get the Constant Run Unloader assembly from Quincy, which will involve a special head with pistons to hold the intake valves open to eliminate pumping losses. And a second air cylinder that drops the engine back to idle when the head is unloaded.

And if there is ever a call for electricity out in the field, say to run a Sawzall for pruning, or flood lights for that 2 AM repair work, you get a small belt-drive alternator head (1 KW to 5 KW) and belt it in parallel with the compressor. (And delete or bypass the idle control when you want power and air at the same time.)

They sell these commercially, search for "air and power" combo.

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