over road air

[larryh]

On my 4905 with original air removed and stripped out I still have the shaft for the compressor drive. What would be the best compressor to mount on it to drive a smaller auto unit to hook to condenser in front of bus driver area?

Any hints or help would be appreciated or PICS???

I'm not a /c man so I need to learn.

Larry Higuera

[kyle4501]

The AC Delco A-6 compressor was a reliable unit & can be had inexpensively (~$110)  for a rebuilt unit. Early 70's chevrolets used 'em.
OR, you could find a Suburban with rear air (& the good compressor) in the junk yard & buy the condenser, both evaporators, compressor & etc. Then you would have an easier time telling the parts guy what you need when it comes time to service the system. 

Just make sure you spin the compressor in the right direction as you have a left hand motor.

FWIW, Most car compressors are in the 3 ton range.

[uncle ned]

try vintageair.com

[uncle ned]

also try classicautoair.com  in tampa fl

[luvrbus]

Larry, when you get back to Quartzsite Arizona Mobile Air can fix you up with any part you need and they are on the west side of Phoenix  www.ackits.com   goood luck and enjoy your cool weather

[HighTechRedneck]

Larry, when you get back to Quartzsite Arizona Mobile Air can fix you up with any part you need and they are on the west side of Phoenix  www.ackits.com   goood luck and enjoy your cool weather

I got one of their complete kits for my Toyota pickup 11 years ago.  It was well packaged, had good instructions and is still going without a leak.

[JohnEd]

I looked into this, only slightly, many years ago.  I learned that the compressors are sized by their internal displacement....in inches at the time no less.  The best and biggest one that was common was the Hitachi( or some Jap name) with a model that had a 10 in the front of it.  That meant it had a 10 cubic inch displacement.  Another number in the Model number was a "6".  That meant that it had six cylinders so there were actually 12 compressions per revolution.  A six is smoother and requires less torque that a five.  I thought I wanted a compressor from a Caddy Sedan De Ville but my AC guy said NO!  NO way.  You want the XXXXXX off of a Jeep.  That was the Jap one....go figure.  but it was the most plentiful and cheap and he said it was the most reliable and larger than the Caddy .

The name's must have changed by now as this was long ago but I think the method of selection and other "lessons learned" might be helpful to you.  Make sure you get a unit that is designed for 134 stock.  Three to sounds about right.  36,000BTU...holy cow.  That's three roof units.

I think you might want to take a belt off of that drive system you have.  Belts cost you MPG and many belts cost mucho.  Also, you don't need those BIG BEEFY belts that are hard and spendy to run.  Get a car belt calibre.

If you are truly handy you could use the climate control from a Lex.  Get everything from the car you need as it has so many sensors and actually anticipates the heat load by the angle of the sun coming in the front.  It seems to have everything in one assembly under the dash plus the sensors are spread out.  Heat and cooling in one unit and it will mix the two for humidity control and that is a big concern in a coach that is sealed worth a darn.  Mine had rivers of water run off of the window alu in the winter so a heater with a dehumidifier would be great while underway.  There were two of us plus two dogs that absolutely insisted on breathing.  All of us were peculiar in that respect, actually.

Good luck bro Knut,

John

[busnut104]

I installed a Welsh unit, The compressor mounts above the blower gear box.

[larryh]

I guess I should of explained my drive is a shaft drive my 8V71 has no belts no place nNADA. I know I will probably make a jack shaft coming off the shaft drive or turn a flange on the lathe and make my own mount. The 4905 has a condenser up front in the heater compartment I want to make both usable as long as feeding these ponies may as well load the camel.

Does it make a difference which way the compressor turns?
thanks for the links will be checking further.

Larry Higuera

[tekebird]

note the location of the two truck style compressors just rt of the fan.

this is a factory OEM retrofit on the late model buffs

[kyle4501]

Does it make a difference which way the compressor turns?
thanks for the links will be checking further.

Larry Higuera

Depends on the compressor:
The porting,
The valving,
How it oils itself,
Placement of the pressure relief valve,
Etc.

[kingfa39]

Larryh, check out this website and find my a/c set up, i dont even need anything else going down the road, has been a excellent system, my son and i put it on the bus in 1.5 days, the jap compresser works really well
Frank
http://www.cruiser-magazine.com/

Fixed Link. Richard

[kyle4501]

http://www.cruiser-magazine.com/franks_dash_air.html

[Bob Belter]

Ahoy, Larry,

I am using two (2) of the old GM A-6 compressors as found on any of the old GM cars of the ~~70's.  I re-sealed them and use R-22 refrigerant.  VERY powerfull--  My down the road cooling in my -01 Eagle is just fine.  They are easily available, and low priced.  They have a little lube pump inside, and must turn the c\same direction as in a car.  An A/C professional told me that these are the most reliable of any units.

Enjoy  /s/  Bob

[TomC]

Because of the expansion valve on automotive A/C's, there is no such thing as too big of a compressor with proper sensor setup.  With a too big compressor, first the expansion valve will cycle to get the proper pressure, and if the compressor creates too much pressure, the high pressure sensor will just turn it off until pressure comes back down again.
Compare that to a too small compressor that will be running continuously, quite possibly not creating enough pressure at the expansion valve to make sufficient cooling power.
The bottom line is that you need to have a large enough compressor to first pump the freon from the rear to the front of the bus (typically) and then enough pressure left over to pressurize the expansion valve.  The mentioned A-6 GM type compressor is powerful, but there are compressors by Sanden and others (especially scroll compressors rather than piston) that will put out as much or more CFM with less horsepower input.  Always have an air conditining expert balance the parts-there is nothing more frustrating than to try to get a powerful system going reliably.  Good Luck, TomC