[Toygeek]

I am considering building a portable (not underhood, just portable) compressor using a gas motor and a york compressor.

I was going to use something simple like this kind of motor:

Of course being the cheapskate that I am, I'd find a used motor. But, how big of a motor do I really need?

Thanks alot

 

[GloNDark]

we are putting one together for my buddy using a starter motor, and some cables to the battery. When all is said and doing it will be in a box with 2 battery terminals, and 2 quick connect fittings.

 

[Toygeek]

That sounds really neat!

I am looking to make it gas powered, so that I can put it on a trailer and have air wherever, not just at my truck. I am also considering making it 110V optional so that I could run it off of 110V at home and use it as a shop compressor, with the trailer in the garage.

But for now I'm happy to have it be gas powered. I just need to know HOW big of a motor I'm gonna need.

EDIT: Oh yeah the other idea was to put an alternator on the belt too, so that I could make a homemade portable welder, like the one shown in the tech section. Possibly even use it as a generator in certain situations, if I wired it up right

 

[4x4 Pete]

Small block Chevy should do it.

 

[JIM3030]

I would say the one you get for cheap or free will be the right HP

 

[Maine Jeepah]

Try a 2 cycle weed wacker motor and tell me how it goes...thats always been my plan in my head...nice and small...would sound pisser all revved up and good on gas.

MJ

 

[coyote]

I've seen them done with 3.5 hp but 5 hp makes it nicer.....

 

[mytzlflick]

this would depend on gearing and how much air volume you need, buy the cheapest engine you can get and then gear it till it works, if its not enough buy bigger.

 

[dieselcruiserhead]

Try a 2 cycle weed wacker motor and tell me how it goes...thats always been my plan in my head...nice and small...would sound pisser all revved up and good on gas.

MJ

PIssah uh? Sounds like a Mainah to me :flipoff2:

 

[toyzilla]

we are putting one together for my buddy using a starter motor, and some cables to the battery. When all is said and doing it will be in a box with 2 battery terminals, and 2 quick connect fittings.

Tell me more about this.

 

[Pazuzu]

we are putting one together for my buddy using a starter motor, and some cables to the battery. When all is said and doing it will be in a box with 2 battery terminals, and 2 quick connect fittings.

Got smoke?
Be sure to get the lifetime warantee and the cheapest starter you can get, and make the mechanical mounts simple, since you're going to be swaping that thing every few trips

 

[Toygeek]

I've seen them done with 3.5 hp but 5 hp makes it nicer.....

That's what I needed to know! Thank you

 

[toy 4 rox]

Got smoke?
Be sure to get the lifetime warantee and the cheapest starter you can get, and make the mechanical mounts simple, since you're going to be swaping that thing every few trips

whys that? i don't think it would burn them up that fast.low drag and with a tank it would not run that much.i have been in the plans to make one for a long time, as soon as pic-n-pull has a 1/2 price day seems to be a good way to go and you could mount it any were.make a cupler to conect the two shafts and mount it.

 

[Pazuzu]

whys that? i don't think it would burn them up that fast.low drag and with a tank it would not run that much.i have been in the plans to make one for a long time, as soon as pic-n-pull has a 1/2 price day seems to be a good way to go and you could mount it any were.make a cupler to conect the two shafts and mount it.

If you gave it enough room to vent, and maybe some cooling fins, you could pull it off, but starter motors are hot mo-fos, and running them that much (minutes at a time, couple of times a day) would eat them up pretty quick.

 

[Tippy]

Keep us posted. I've been contemplating this myself. I snagged a couple of 5 hp B & S inteks from work when we switched everything to Honda's. They were still good so I grabbed a few. I was going to make a small cart and use a air tank from a semi truck.

 

[ChiScouter]

Keep an eye out for handicapped vans. I recently found one in the boneyard with a 12v motor and gear reduction box that cantilevered a platform in and out of the van. I plan on trying out that motor with a small compresser. Also many of them have nice electro/hydraulic pumps and linear actuators

 

[OverThrottle]

If you gave it enough room to vent, and maybe some cooling fins, you could pull it off, but starter motors are hot mo-fos, and running them that much (minutes at a time, couple of times a day) would eat them up pretty quick.

I have some experiance with these. I built a battlebot where the weapon was powered by a standard GM starter motor. We tried various starter motors that we could find that would mesh up with the flywheel we were using (It used a GM flywheel as well) and when ran at 100% dutycylcle we would burn a motor up in anywhere from 5 - 10 minutes !!

They were definitely not designed for continous use of more than a few seconds at a time. The problems are that they draw a huge amount of current, as they use series coils instead of perm. magnets, and they have bushings instead of bearings.

 

[OverThrottle]

I once saw an electric wholesaler that sold two Ford electric fan (radiator) motors that were set facing each and had a shaft coupling them together for $ cheap. It was a kit that was designed to turn a bike into an electric scooter. If I can find a link, that would be perfect for this app. It was compact, had decent torque and very high RPM. Add a belt and pulley of the right ratio and you have a perfectly reliable and powerful drive motor.

EDIT:

I can;t find the setup I was thinking of (I think they stopped selling them), but I imagine you could build the same thing fairly easily with electric fan motors from a pic-n-pull. They are compact, lots of torque, high RPM, and can run all day long. If you use a belt system to reduce the RPM's (you would have to reduce the RPM somehow) you could easily put two motors on the same belt (position your three pulley's in a triangle config) and double your torque.

 

[merv]

They were definitely not designed for continous use of more than a few seconds at a time. The problems are that they draw a huge amount of current, as they use series coils instead of perm. magnets, and they have bushings instead of bearings.

I thought only cheap winch motors had perm magnets, and the good ones were series coils? I guess it's the bushings that do it then?

 

[OverThrottle]

You could be right about the perm. magnet part. Your right some winch motors use series wound magnets.

I imagine the heat comes from both the bushings and the huge amount of current. I don't think starter motors are all that efficient. I imagine since they only need to run a few secs. for thier intended purpose the manufactur's don't waste money improving them.

If they are not efficient, then at the current draw they pull (over 300 Amps initially, and then dependent upon load therafter) they build lot of heat really fast. It doesn't take too long before the heat is enought to melt the enamal on the windings.