OTR A/C compressor

[JohnEd]

Nick and all,

I have a coach AC compressor on an old unit that is a YORK as I used to call them.  I thought that they were outdated and I could get more ci of displacement and less operating power consumption using the wobble plate design found throughout the auto industry today.  Imagine my surprise when I looked into the thermoking unit (Red Dot) and found that it was using what looked like a York.  Long ago I had an aquaintance that did auto AC fo a living.  He got a call to service AC on the giant earth movers working east of San Diego building I-80.  I said long ago!  Any way he replaced a lunched York on one unit.   Next day he got a call for anothe failure.  York R&R fix.  Day later it was two of them and the one he had already replaced.  GHe concluded that the monster diesels had so much shock in their normal operation that the York piston was being slamed around and failing.  Tirned out to be true, he said.  Any way, he converted the entire fleet to those GM typt wobble plates and he only had calls to recharge systems.  Said not one of the ever failed in 6 months that he had the contract and prior to that the Yorks were lasting less than a week.  Now I see where that design is being recommended for large diesel truck engine applications.  So wich is it, wobble or crank and piston.

Thanks

John

[Nick Badame Refrig/ACC]

Hi John,

By "Wobble" do you mean rotory or scroll?

Piston compressors are commonly used in large vehicles "busses, Rail, and Trucks" and rotory compressors are now preasant in most newer cars.

The rotory type are much more efficiant for their duty in cars and suv's.

Thoose old Yorks went out with the 80's. I recently replaced one in a 1985 Coachman Motorhome. My friends at Polar Bear supplied it to me.

Hope this helps
Nick-

[JohnEd]

Nick,

Yes, it does help.  I was under the impression that the rotary was more efficient, as you have confirmed.  Believe it or not I need to convert that system over to 134 and i want to replace the compressor while I have the system open.  That brings up the next question: which compressor to use?  I will not be using a new compressor but will get one out of a scrap yard.  Around 1990 I was told to use a compressor off of a jeep wagon.  It was of Jap mfr and had a part/ model num,ber that indicated that it was displacing 10 cubic inches.  Is that the biggest automotive compressor that is "popular" and "reliable" and inexpensive.  I was surprised that the Jeep unit was larger than the Cadilac but that was his info.  How many thousand BTU's could I get from a 10 cubic incher.

I have friends that rigged the york types to be air compressors.  They worked for years and I was amazed.  Can you also use the rotary compressors to serve as air compressors?  I always liked the thought of having an air compressor that was engine driven and coupled through a magnetic clutch so its parisitic power consumption was held to a min.

Thank you for your expert opine

John

[Barn Owl]

I have also seen old A/C compressors used as air compressors.

[kyle4501]

I've always had the most sucess with the old A6 GM compressor. Never had to replace one. My experience with the R4 compressors includes lots of R&R. (Yes, I replace the oriface tube/ expansion valve & receiver/dryer when ever I open the system & pull a vacuum for several hours after flushing the system before I replace the oil & freon.)

http://www.smp-training.com/Counterman/TCDAC/ACSystems/Pages/ac13.html

That oil sump & oil pump along with the cast iron liners must be part of the longevity.

[tekebird]

GM offered as a retrofit a kit to run one or Two GM Car style compressors instead of the big PTO powered Compressor.  On the last units this retrofit was available from the factory.

both of my Dad's 4108 have this, one with a single and one with a pair.

they work great.

[DavidInWilmNC]

As to A6's and R4's... our old GM cars had A6's and never had problems.  My later GM's, in the '80's, had the R4's.  They sucked.  I believe the A6's are self-lubricating vs. the R4's being lubed by the refrigerant.  I know we just had to replace an R4 on an '95 MB 300D turbodiesel.  I noticed on Carrier's site at http://www.transportaircon.carrier.com/details/0,2806,CLI1_DIV8_ETI268,00.html?SMSESSION=NO the A6 is said to have a capacity of 60K BTU's.  Is this for all A6's or is this model something special?  It sounds like it could be used to make a hell of a driver's (and front living area) system if matched with two evaporators.  One could be located in the dash and the other elsewhere... in a cabinet, a bay, etc.  In fact, I seem to remember seeing pics where one guy used a system similar to this and had the evap. in his dinette bench, but I can't seem to find it.  As my OTR a/c is working currently, I'm not really needing any additional A/C, but one never knows how well this old system will hold up. 

David

[FloridaCliff]

Doug wrote:   GM offered as a retrofit a kit to run one or Two GM Car style compressors instead of the big PTO powered Compressor.  On the last units this retrofit was available from the factory.


Does anyone have a picture of the mount Doug described?

Would like to make one of my own.

Cliff

[JohnEd]

Ya'all,

Thank you one and all.  The York is headed for the scrap heap.  The A6 seems the hot ticket and I will put my request on the line.  The A6 also seems the prime candidate for a compressor, also.

Those links you gave me were very good.  If the A6 can do 60K btu's I won't need two to do the coach for my OTR system. Thanks again

John

[tekebird]

I will take a photo next time I am at one of the buses....Will have to be at my folks place as I can't find my camara's download cable

[FloridaCliff]

Doug,

Many Thanks in advance....

Cliff

[tekebird]

you can make it out a bit here.

not the best pic...but what I have on hand until I see the bus again

[FloridaCliff]

Doug,

I didn't even think about mounting it like that!

Any close ups of mounts, pulleys will be appreciated.

I am NOT to proud to copy a working system.   

Cliff

[tekebird]

will post better pics when I can

[tekebird]

here you  go