Changfa clone?

[rcavictim]

That's a nice looking unit.
What generator head are you planning on driving with it?

Veggie



Thought I would use a Harbor Freight at the start of the project 299.99
.
Now I'm thinking of a Voltmaster* like Veggies or a PM like George's from utterpower.

Any input would be welcome.

I think I want as good and clean power as possible out of this generator.

Also I'd like to have a 12 volt alternator, and air compressor with an electric clutch. I would only use air or electric not both, and probable have separate tank.

Anybody do a compressor, any ideas?

Thanks
Bill

If you could figger out how to keep it lubricated an a/c compressor with built in electric clutch pulley from a automotive application would be a sweet air compressor.  I made a shop compressor many years ago from cast iron twin cylinder refer compressor heads that held oil in their crankcase but due to the lack of oil control rings on the pistons the lube oil would quickly be pumped out with the air being compressed into the receiver tank.  I had to top that thing up constantly.  Pain in the you know where!  Where I was and when I did not have the coin to purchase a real compressor head from Princess Auto.  You do what you can with what you have.

That is a nice looking engine.  It is remarkably similar to my slightly smaller 175A engine.  I wish mine had e-start as does your's.

[WGB]

That's a nice looking unit.
What generator head are you planning on driving with it?

Veggie



Thought I would use a Harbor Freight at the start of the project 299.99
.
Now I'm thinking of a Voltmaster* like Veggies or a PM like George's from utterpower.

Any input would be welcome.

I think I want as good and clean power as possible out of this generator.

Also I'd like to have a 12 volt alternator, and air compressor with an electric clutch. I would only use air or electric not both, and probable have separate tank.

Anybody do a compressor, any ideas?

Thanks
Bill

If you could figger out how to keep it lubricated an a/c compressor with built in electric clutch pulley from a automotive application would be a sweet air compressor.  I made a shop compressor many years ago from cast iron twin cylinder refer compressor heads that held oil in their crankcase but due to the lack of oil control rings on the pistons the lube oil would quickly be pumped out with the air being compressed into the receiver tank.  I had to top that thing up constantly.  Pain in the you know where!  Where I was and when I did not have the coin to purchase a real compressor head from Princess Auto.  You do what you can with what you have.

That is a nice looking engine.  It is remarkably similar to my slightly smaller 175A engine.  I wish mine had e-start as does your's.

I have done the refer compressor thing too, know what you mean with the oil! I'm using an old open drive for a vacuum chamber now, but may change it back to refrigeration duty with the Listeroid.
I was going to just use an electric clutch modified to a standard compressor, didn't think about the real compressors made for that duty like on tire service trucks.
Thanks I'll have to look into that option.

[vdubnut62]

Why not just use a self regulated air compressor from a truck or school bus? The compressor comes with a pulley mounted,
it can and does run constantly, but has what is called a govenor that stops it from building air at usually 100-125 psi.
Mine came from a 85 GMC school bus with a gas engine and air brakes.
Ron

[WGB]

Why not just use a self regulated air compressor from a truck or school bus? The compressor comes with a pulley mounted,
it can and does run constantly, but has what is called a govenor that stops it from building air at usually 100-125 psi.
Mine came from a 85 GMC school bus with a gas engine and air brakes.
Ron

Sounds good, got any pics?

[vdubnut62]

Not any handy, I'll get a few next time I'm up at the farm where the bus is.
Ron

[mobile_bob]

most all of the truck mounted aircompressors that are belt driven and all that are gear driven
have to have pressurized oil from the engine to feed the compressor main and xdrilled crank
to the rod(s) brg(s).

there were a few old mid size chevy's and fords that had self contained compressors, but they likely will
be very rare find these days and likely worn completely out.

if you look for a large capacity york AC compressor as used on ford cars, pickups and most all mid
and heavy trucks up until the last decade or so, they if mounted vertically will maintain their oil pretty well.

climate control is the manufacture of what was once the york compressor and they come in 3 different displacements
so knowing which is the high capacity is a benefit,

with a simple water pressure switch you can control the clutch and by extension the cutin and cutout of the compressor
and set it to cycle between perhaps 120 and 140psi which is within the working pressure of most tanks.

for a tank go to a trailer shop or trailer parts and repair place, they will have a broad selection of new tanks that are DOT
approved and therefore safe for this project, and they are very competitively priced. while there ask them for a pressure
safety relief valve, which is also cheap insurance for your system.

should you find that after you get it running that you would like a faster recovery time:

1. be sure to size your tank to no more than approx 5-7 gallon if you want to use an impact gun, because the cycle time will be
acceptably short.

2. if you want to dramatically cut your cycle time, and if you have a dual pulley clutch, piggyback a smog pump to the compressor
and have it supercharge the compressor inlet port, the smog pump will move many cfm at approx 30psi which in effect turns your system into a 2 stage compressor.

3. with a small solenoid that is triggered by the second set of contacts in the pressure switch, they come with dual contacts and you
are only going to need one for the clutch operation, you can set it up to trigger to engine fast idle when the compressor cuts in, and release to low idle when the compressor cuts out.

i have built several of these systems over the years and can run a 1/2" impact well, and up to a 3/4" impact to take down bud nuts
off of hd truck/trailer wheels with an approx 20 second cycle time between nuts, which is not bad for a compact, cheap and easy to
put together compressor.

as for tire truck compressors, good luck charlie!!
most that are on the secondary market are either (a) used up, (b) no parts available, or (3) insanely expensive
a new compressor for a tire truck runs approx 10 grand for the whole setup, and i suspect the compressor is the majority
of the cost. they also consume more hp than most folks have available to drive them, especially if you want the pressure
and volume they are designed to deliver,, figure minimum of 16hp to drive one.

another option is one of those Vtwin compressors from harbor freight, they are twin cylinder single stage units that look to be able
to provide maybe 12cu/ft/min at 90psi, and are made to pump up to an advertized 140psi but i would not run one past 120.
they are about a hundred bucks when on sale.  you would have to devise a clutching mechanism or an unloader valve system to
open the compressor discharge from the system and reduce the load, personally i would use an idler system and a small air cylinder
as an actuator, or maybe even an electric solenoid to tension the idler. such a system if done right would be very effective in my opinion
and probably better than the york/climate control system.

fwiw, about what you paid for it



bob g

[vdubnut62]

Hey mobile_bob, I have one of those v-twin harbor freight compressors. The ad says aluminum and cast iron, but it is solid cast iron
block, cylinders, heads, valve plates, and a huge double cast iron pulley. The darn thing is HEAVY. I replaced the compressor on an Ingersol Rand with one of the Harbor Freight units, and I was impressed, made more air than stock. I did however, have to change the motor  pulleys, the compressor is rated at only 1200 rpm.  and it does vibrate a little more than the stock one. There was some dirt in the heads, left over sand I think, so I cleaned that out, the crankcase was clean, I did have one reed valve fail, it was replaced under warranty for free, but took a couple of months to get the parts from china.
I recently saw one of these compressors at the local flea market for 50 bucks. The guy gets Harbor Freight returns I guess.
Ron

[BruceM]

My Listeroid 6/1 runs both generator head (ST3) and a two stage Eaton air compressor.  The generator's homemade AVR allows me to shut down the output relay and totally turn off excitation when pumping air, and the Eaton compressor has pneumatic unloaders in each cylinder so that it freewheels when not being used. (A pilot valve and air toggle switch for enabling it is controlled by an RC servo since my controls are remoted.)  If I have a long day of AC or air use only, and I'm being stingy on fuel, I pop a belt.

Not as nice as an electric clutch, but simple.

What kind of CFM will a large auto compressor put out?

Bruce

[WGB]

Thanks for the info!
I ordered a VOLTmaster AB60 today, I'll see it next week.
http://www.voltmasteramerica.com/products/AB.htm

[WGB]

Hey mobile_bob, I have one of those v-twin harbor freight compressors. The ad says aluminum and cast iron, but it is solid cast iron
block, cylinders, heads, valve plates, and a huge double cast iron pulley. The darn thing is HEAVY. I replaced the compressor on an Ingersol Rand with one of the Harbor Freight units, and I was impressed, made more air than stock. I did however, have to change the motor  pulleys, the compressor is rated at only 1200 rpm.  and it does vibrate a little more than the stock one. There was some dirt in the heads, left over sand I think, so I cleaned that out, the crankcase was clean, I did have one reed valve fail, it was replaced under warranty for free, but took a couple of months to get the parts from china.
I recently saw one of these compressors at the local flea market for 50 bucks. The guy gets Harbor Freight returns I guess.
Ron

Maybe an aluminum piston?
I've look at HF's compressor heads myself.

[vdubnut62]

Aluminum construction with cast-iron cylinder sleeve

That is what the HF ad says. Well I got mine and the only aluminum piece that I have
found IS the pistons, everything else is cast iron.
Ron

[mobile_bob]

i took another look yesterday at harbor freight here in tacoma, the Vtwin compressor is all cast iron
at least all i can see, maybe the pistons are aluminum? i don't know and didn't ask if i could take it apart
to find out either.   

119.95 on sale this month, not bad in my opinion
i am thinking of getting one and setting it up to pump air with one cylinder and vacuum with the other

bob g

[NoSpark]

3.5 HP Changfa clone with over 1500 hours. 

http://www.youtube.com/watch?v=25Zk5-5OfFg

[WGB]

VOLTmaster head.

[rcavictim]

VOLTmaster head.

That VoltMaster head looks much like the unit that used to be in the Princess Auto catalog.  I went looking for one last year and learned that Princess no longer offers such a thing.  Bummer.  Someone probably got a good discount deal when they got rid of their remaining stock.  I wanted one to couple to the 6 HP Launtop air cooled diesel I bought from them.