Outer Limits 4x4 Board

bought an air cond compressor to rig up as an air compressor. unfortunatly the space i had in mind wasnt big enough-bummer.
got me thinking though-why not use a 12v motor to turn the compressor? a friend had an old starter motor lying around, so i grabbed it, bored the front out to take a bearing to support the main shaft. then turned up a pulley for the shaft and got a belt to fit and mounted the starter motor piggy back fashion.
gave it a thourough test tonight pumping into my air receiver. well it works ! but the starter gets mighty hot and starts smoking abit when the pressure gets to about 80psi. had it up to 110psi but very hot ! so unfortunatly will have to put it on the
'well thats a good idea' pile.
any body got any other ideas how to drive the compressor????
cookie monster

Some starter motors will handle that kind of continuous load better than others. I have known of guys using starter motors to run the winch on flat bed tow trucks... however, I've no idea which models you should be looking out for.

Also, did you consider varying the size of the two pulleys so that the starter motor doesn't have to work as hard? ie smaller wheel on the motor, bigger wheel on the compressor?

Failing that, surely there's somewhere you can fit it so it'll run off the engine belts?

yeh, the pulley on the motor is probabley 1/2 the size of the compressor pulley.
i think the main problem is the load. running free the starter is probably doing 2000rpm, under load it must be down to 600 and pulling heaps of amps. jumper lead cable getting warm!!
there is a space in the engine bay, above the alternator, but the compressor is a bit too long. the turbo inlet is in the way.
maybe have to look for a shorter compressor?
cookie monster

How about using a Hydraulic motor (or Hydraulic pump in reverse) and taking an output of the power steering pump.? Gear it up a bit to improve speed as the power steering pump dosent have a huge flow rate. This combo MIGHT be easier to mount?

Nick

you need at a 2.5hp winch motor, but at what cost $$$$$$$$$$$$$$$$$
I tried with one off a 6000lb winch and burnt it out
Bazzle

starter motors are not designed to run continously at high rpm.

they are designed for brief torquey bursts...

they draw a shite load of current and will flatten a battery in no time..

maybe try one of these motors.. dont know if they will have enough power for what you are after.

http://www.oatleyelectronics.com/bcorner.html#SC300

look at the 300 watt model...

You need about 2000watts to drive comp at 100psi

Bazzle

When i installed my first engine driven compressor on my GQ (pre-endless air days) I cut the front end off a SANDEN 508, then made up a short driveshaft to attach to the remaining input shaft of the 508. I then used a truck airbrake compressor mounted at the back of the engine bay driven by the short driveshaft......it worked pretty well. The other thing i've seen (on a GQ) is the aircompressor driven by a mechanical PTO...

Nick

WENT TO 'U PULL IT' THE OTHER DAY AND HAD A WONDER ROUND WITH THE TAPE MEASURE (SHOULD HAVE DONE THAT IN THE FIRST PLACE!!). THE SMALLEST AIR CON COMPRESSOR I FOUND WAS ON AN 87 BARINA. APPROX 165 LONG.
GOING TO FIND ONE 'ON THE SHELF' AND SEE IF WILL FIT ABOVE THE ALTERNATOR. THE ONE I ALREADY HAVE IS APPROX 220 LONG.
KEEP YOU ALL POSTED.
COOKIE MONSTER

Have a look around on some early Range Rovers if you are looking for a small compressor. Some run a very small rotary style pump. Allthough a lot also have the York piston compressors.