compressor

You will need to know the factory electric motor rpm. Then set motor rpm to get your pulley ratio right.

 

It'd take a pretty horsey motor to turn that 4-banger fast enough to do any good.
Then consider that 'good' compression is 120-150 psi. What are you going to get out of a worn out one?
Then, getting the exhaust to hold the pressure is another thing entirely. The way around that, would be to remove the exhaust valvetrain, and put compression tester insterts in the spark plug holes, with check valves.
Suppose you would need some water in the block, to counteract heat from friction/compression?

Basically, it sounds like a lot of work, for something that won't work very well.

 

air pump

All a motor is is an air pump. I don't see a problem with it. What is interesting is what are you going to do with 400 cfm of air?

 

How about running the motor on2 cyls. and use 2 cyls for a compressor? I have seen this done with a air cooled VW,On the web. they were for sale,A long time ago Jerry

 

How about running the motor on2 cyls. and use 2 cyls for a compressor? I have seen this done with a air cooled VW,On the web. they were for sale,A long time ago Jerry

I was wondering about that myself. I didn't know how the Mazda would respond to it.

Something else. You'll have to run it at least idle rpm, or you'll starve the mains, and burn out the bearings. I'm back to the "horsey drive motor" thing, again.

 

It'd take a pretty horsey motor to turn that 4-banger fast enough to do any good.
Then consider that 'good' compression is 120-150 psi. What are you going to get out of a worn out one?
Then, getting the exhaust to hold the pressure is another thing entirely. The way around that, would be to remove the exhaust valvetrain, and put compression tester insterts in the spark plug holes, with check valves.
Suppose you would need some water in the block, to counteract heat from friction/compression?

Basically, it sounds like a lot of work, for something that won't work very well.

A) I'm not sure I understand why the engine would need to spin particularly fast. Seems to me it could spin at the same speed as a normal 4 cylinder compressor - and maybe even a little slower since the Mazda would most likely have more cubic inches than the normal compressor.

B) Couldn't a person operate nearly any air tool or media blaster with 120 psi?

C) I think taking the air off at the spark plug holes is the way to go. Seems the simplest to me. Not sure where to find an air check valve for the application however.

D) Hadn't thought about the heat build up. Air cooled compressors certainly produce a lot of heat so its a question that needs to be dealt with in any experimentation.

How about running the motor on2 cyls. and use 2 cyls for a compressor? I have seen this done with a air cooled VW,On the web. they were for sale,A long time ago Jerry

That's a very interesting idea...although running two cylinders would produce even MORE heat to get rid of, but you then have the option of running the regular water pump and a radiator set up outside the garage. However, I would think over the long (or maybe short) haul the 4 banger wouldn't be too happy firing on just two.

 

I remember reading somewhere it takes something like 11 horsepower to turn a Chevy 350 at 2000 RPM's, the Mazda might get away with a 220 volt 5 horse motor to drive it.

Either way you go there IS a need for cooling and oiling the engine similar to it being used in an automotive application.

 

At a museum in Gunnison, CO, there is a self contained compressor consisting of side-by-side model A motors. One drives the other. Yes it has been done.

 

Several of the commercial companies make these conversions for gas powered compressors. The Ray Greene company made them using a Wisconsin V4, two cylinders run, two compress air. There is also one using a 351 Ford, running on 4 cylinders, and a special head on the other side to compress air. I've also seem old ones made by the Jager company that used a flathead Ford V8 with one special head.

 

enjenjo beat me to one -- running a V-8 on four cylinders and using the other bank as a compressor. Requires a special camshaft and intake manifold, of course.

I've seen articles for converting one cylinder lawn mower engines into compressors. Take carb off and mount a filter for air intake, remove camshaft an install a one-way valve in the exhaust port (similar to a PCV valve). The intake valve spring is removed and a light spring, just enough to overcome the weight of the valve, is used. The intake is sucked open when the one-way valve is sucked shut by cylinder vacuum. Or a second lobe could be welded up opposite the existing exhaust lobe on the camshaft. Don't know if any of the articles are online.

 

I have not seen one in a number of years but a company used to make a special head for a flat head jeep 4 banger. It had regular compressor valves built int two of the cylinders. Pumped a fair amount of air.

 

The Vw modification uses a modified Cam shaft and Runs Off the #2 and 4 Cyl. where 1 and the 3 are used as the Air Pum...

Oh.. and the specs... 100% duty..
56!!!CFM @ 120 PSI...


YEAH 56!!! last time I saw the kit was like 265 or something...

if People are interested..I dig the link back up...

 

At a museum in Gunnison, CO, there is a self contained compressor consisting of side-by-side model A motors. One drives the other. Yes it has been done.

Hehe, I came across one of those at an abandoned mine site just outside of Boulder. It had 2 flathead 4's, with the clutch ends facing each other. I don't know what the motors were, but they were different from each other. The whole thing was mounted to what was left of a truck chassis. It was pretty nifty I'll admit. Definately showed some ingenuity! I should take some pix of it and post it, but it;s suppose to snow like heck tonight.

 

Maybe it would be a little more practical to use a motorcycle engine or a twin lawn tractor engine. These are oil lubricated and air cooled for simplicity. Didn't Firefly's and Geo's come with 3 cyl motors too?

 

The Vw modification uses a modified Cam shaft and Runs Off the #2 and 4 Cyl. where 1 and the 3 are used as the Air Pum...

Oh.. and the specs... 100% duty..
56!!!CFM @ 120 PSI...


YEAH 56!!! last time I saw the kit was like 265 or something...

if People are interested..I dig the link back up...

Yes I am interested. Get that and a good used tank and I would be in business.

 

if you do try taking the air from the plug holes, you might be able to use a check valve and hose from a cheapo compression testerand then hook them into a four into one manifold. interesting idea. not so sure i would be worried about cooling system as you are not causing any combustion , but i think oil would be needed.

 

Just curious....Other than bragging rights, why would you want to put the time and money into building an 'engine' compressor? Why not just shop around and buy a decent compressor? I am not trying to be a downer, just curious as to why.
Later,
WEIMER

 

If you could build an engine compressor for $400 with comparable output to a 2-stage unit with a price tag of $1,000 - who wouldn't?

Obviously the big question is - can the above be done. To me it's at least worth exploring.

Dewey

 

I would think that you would have close to $1'000 in trying to build one out of a car engine...after you buy the engine, the eletrical motor(if you go that route) the tank, all the trial/error parts, etc....I may be way off here also. Also, if you are buying a good 2 stage for $1'000, that seems a little on the low end also, so It may be worth it to try out something new. Thats how new inventions come about right?
Good Luck, and keep us posted:thumbup:
Later,
WEIMER

 

When I was a kid. The guy who painted our barns used a four cylinder engine that ran on two and pumped air with the other two cylinders. He ran the engine at about 1800 RPM. It was enuff to run two spray guns shooting barn paint..

Another thing... We used to carry a tool box on the tractors. In the tool box was a spark plug wrench with a gizmo that Ford marketed. This device was a check valve that went in the spark plug hole and a hose with an air chuck on the other end. If you had a flat, in the field. Remove the s-plug. Insert the check valve thingy and start the tractor. Instant air!! worked good. Tho there were fuel fumes in it.

 

I think it would only be worth it if you already had a spare engine or electric motor to use. I suppose if the engine was any good, you could sell it and use the dough towards a new compressor....Its still neat to see what people can do with a little ingenuity though...Anyone know what size electric motor would be required to run a 4 cyl compressor?

 

No need to reinvent the wheel. Heavy construction companies use "Tagalong" compressors every day. The ones that I have seen and purchased have a Ford 351 where 4 cylinders run the motor and 4 compress the air. The are very common, and I picked one up at auction this summer for $300. You would just have to make the connection between the tagalong and your tank, since they only have a minimal storage tank. Although with the amount of cfm that they put out, storage and running is not really a problem. Whatever way you go you will need good water & oil traps. Check out your local newspaper for heavy equipment auctions, even one that is pretty beat would probably last a hobbyist a lifetime.

 

Toyman,

Is there any special provision for cooling the engine? I assume, since the motor is actually firing, that you have to circulate the engine water through a radiator. And, to your knowledge, does it have the stock oil pump?

 

No need to reinvent the wheel. Heavy construction companies use "Tagalong" compressors every day. The ones that I have seen and purchased have a Ford 351 where 4 cylinders run the motor and 4 compress the air. The are very common, and I picked one up at auction this summer for $300. You would just have to make the connection between the tagalong and your tank, since they only have a minimal storage tank. Although with the amount of cfm that they put out, storage and running is not really a problem. Whatever way you go you will need good water & oil traps. Check out your local newspaper for heavy equipment auctions, even one that is pretty beat would probably last a hobbyist a lifetime.

Sorta like this
http://cgi.govliquidation.com/auction/view?id=503593&convertTo=USD
If one was reasonably close, I would consider something like this, overkill I know, but would be able to run any air tool.

 

Compressor from A/C compressor

Here's a different approach. I'm looking to make a small compressor for the house, mainly for a miniature sandblasting cabinet for the wife's jewellery shop. I've got an old nippondesso A/C compressor that I might try this with. Thinking of using an old propane tank for the receiver. Anyone find any other articles on this subject, please post. http://www.motherearthnews.com/arc/3616/