Automotive Air Conditioning Information Forum (Archives)

Provided by www.ACkits.com

We've updated our forums!
Click here to visit the new forum

Archive Home

Search Auto AC Forum Archives

GM R4 upside down?

CJDave on Tue June 05, 2007 9:59 AM User is offlineView users profile

Year: 1983
Make: Mercedes
Model: 300SD
Engine Size: 3L diese
Refrigerant Type: r134A
Country of Origin: Germany

Ok, So now I have my new R4, but the clocking for the plug is different from the original. Somewhere I read that the R4 has a oil passage to the front bearing and if it was mounted upside down it won't oil the front bearing. I also read that there is a x on the casting where that oil galley was. The old compressor has the x at the top when mounted the new one they sent me has the x at the bottom when mounted. I know for my application the compressor is mounted upside down when compared to the GM applications (hoses come out on the bottom instead of the top).
So Will it work ok? is it going to burn up in the first 3 hours? can I rotate the body somehow? and still have the hoses come out where they need to?

Thanks
-Dave

TRB on Tue June 05, 2007 12:17 PM User is offlineView users profile

Can you supply some images of this compressor mounting? Very odd to have a compressor mounted upside down. Myself I would not run a compressor in that mode. Maybe Mercedes is doing something different here. We don't work on many Mercedes in our shop.

-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

CJDave on Tue June 05, 2007 12:37 PM User is offlineView users profile

Let me see if I can get some pictures. The compressor is mounted down under the power steering, basically under the engine. and the ports are below center. I think Mercedes had them built to work upside down, but all the replacement compressors are setup for GM applications in the standard upright configuration.

Dave

Chick on Tue June 05, 2007 2:29 PM User is offlineView users profile

On some there is an "X" that should be right side up..I checked about five I have here, and the only one with the X is an older R4, I have a couple service compressors, and aluminum with no markings at all. I will post a pic when I get home..I did read somewhere that Mercedes did have a concern that the X be facing up, which on a GM is right behind the coil..But I have done more than a few and used GM R4's and as you said, the lines are to the side not flat accross, and I have never had a problem..So I would just check yours and see if you have the X...I'll post the pic later..

-------------------------
Chick
Email: Chick

---------------------------------------------

Freedoms just another word for nothing left to lose

CJDave on Tue June 05, 2007 3:53 PM User is offlineView users profile

Chick,
Both new and old (as far as i know original) compressors have the X. But the x is on opposite sides on the new one. If I put the new one on the x will be pointing straight down. the old one had the X pointing straight up????

Thanks
Dave

Chick on Tue June 05, 2007 3:59 PM User is offlineView users profile

I have heard that in the past, but never had a problem using a Chev R4 on a Mecedes.. But for those who may be able to shed light on the subject, here's a pic..The "X" is always behind the coil connector..As I said, I have several on the self (used) and only two have the X..So I am really not sure..Perhaps a mercedes message board would help, or Bohica should be by, and he's tops on those cars, and GM tech with GM compressors..Anyway here's the pic..(Should be noted that is has to do with the internal bearing, not the clutch bearing..)

OK, I don't know how the other pic over rid my pic... So here it is again..Must have ad the same name...????


-------------------------
Chick
Email: Chick

---------------------------------------------

Freedoms just another word for nothing left to lose

Edited: Tue June 05, 2007 at 7:04 PM by Chick

jbaj007 on Tue June 05, 2007 4:33 PM User is offlineView users profile

On the R4 there are two oil channels, machined into the inside of the yoke, that originate at the "X" area and feed downward to the front needle bearing and to the shaft seal (which needs oil to seal correctly). To switch it to the bottom (Mercedes top), pull the clutch, to be able to get the four yoke hex head screws out, and rotate the yoke 180º. Reverse to assemble, making sure you set the "clock" of the clutch electrical connector to the correct Mercedes position. That said; supposedly the ACDelco techs say that they haven't heard of failures due to "X" position, but it can't hurt to get oil to the bearing and the seal using gravity rather than just diffusion. FWIW.

ice-n-tropics on Tue June 05, 2007 5:17 PM User is offline

007,
Another thing on the R-4 subject:
Can you shed any light on process to reduce porosity leak through the compressor housing by improved gravity casting process or post machining sealing method? The Humvee occupants in IRAQ need full time A/C from the R-4.
Cordially,
ICE


-------------------------
Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

CJDave on Tue June 05, 2007 5:26 PM User is offlineView users profile

Here is a picture of how the ports are oriented on the Mercedes.


I will get you a pic of the x location on the compressors.


is the yoke easy to rotate? just pull the 4 bolts out and turn it? or do I need to pull it out all the way and put it back in in the correct orientation?

Thanks
Dave

Edited: Tue June 05, 2007 at 5:32 PM by CJDave

CJDave on Tue June 05, 2007 5:39 PM User is offlineView users profile

Here is a front pic of the old compressor


Here is a front pic of the new compressor looking down as if it was mounted in the car.



And here is a pic of the new compressor looking at what would be the bottom if mounted in the car:



-Dave

Edited: Tue June 05, 2007 at 5:43 PM by CJDave

jbaj007 on Tue June 05, 2007 8:16 PM User is offlineView users profile

Ice-in,
I don't have an answer . Seems like a lot of heat, men and material to cool down with an R4. Doesn't seem fair to our troops. The HT6 and clones with either mounting ears or mounting tubes would circumvent gravity cast porosity problems by keeping the mounting bolts OUT of the cast body end plates, unlike the R4 that has the mounting bolts thru/into the casting. I'm sure that the mounting holes directly in the body of the R4 adds to the problem; greater exposure of porosity and all?, distortion from mounting stress and vibration? I wish I knew how to help the problem, but you're way out of my league.

Dave,
I removed the yoke to verify the oil channels, and then installed it where I wanted, but I think it would just rotate to position once the hex head screws are out.

Edited: Tue June 05, 2007 at 9:38 PM by jbaj007

bohica2xo on Tue June 05, 2007 8:25 PM User is offline

Tex:

The big issue with the R4 is this:



Once installed, you remove the above item - and wait for the inevitable.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

ice-n-tropics on Wed June 06, 2007 3:47 PM User is offline

bohica,
The R-4 grenades with very little hesitation. You probably have a story behind that reminder that is pictured.

007
True, the R-4 isn't up to the task. Problem on the Humvee GM diesel is difficulty of mounting anything but a pancake compressor. The up-armor field installed A/C uses the Sanden SD7H15 but the engine dress gets several mods that the OEM doesn't want to do.
Cordially,
ICE-n-TEX

-------------------------
Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

bohica2xo on Thu June 07, 2007 4:07 AM User is offline

Tex:

The York would be a better choice for a combat vehicle than an R4 - heck, the only WORSE choice would be a Tecemseh 980!

There is always plenty of time to put that pin in your pocket if you are "cooking" properly...


B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

ice-n-tropics on Thu June 07, 2007 11:25 AM User is offline

B,
About 58,000 Great Americans gave the ultimate sacrifice over there, while doing their best. None of us is in charge of our time line, we can only be diligent to tweak it in our favor by "cooking" properly.
May God, the Father of Jesus, bless our troops and the Brits too.

My old R-12 HR980 is still cooling with no measurable leak yet.
Cordially,
ICE

-------------------------
Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

bohica2xo on Thu June 07, 2007 12:54 PM User is offline

Ok Tex, you are right as usual - nothing is worse than the R4!

On the other matter, my mentor would pull the pin - and have a casual conversation with you while tucking the pin in his pocket. I never had much of an "arm", so I became a chef - if you are not going to toss it very far it should go off when it gets there...

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

ice-n-tropics on Fri June 08, 2007 2:19 PM User is offline

B,
The HR980 has those steel mounting lugs outside the outer circumference, therefore the R-4's cast through holes are avoided. Tecumseh, who made the HR980, had a better idea than Harrison/Delphi. My daughters R-4 is not enviro friendly and I wipe the oil streak off the inner fender like Tim does with his other compressor.

Best to leave those devices alone if your one of the guys who can't throw very far. Other guys can shoot a long distance target.

Bill, my friend caught up in the present civil war, is the shooter, so he gets the Cat Bird seat in the top of the Humvee when not on sniper duty. Bill's sure ready to get back to his wife and 3 kids on his old job teaching auto mechanics at the Jr. College. His wife gets lots of prepaid calling cards from helpful friends. He doesn't see how we are making any friends.
Cordially,
ICE

-------------------------
Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

Back to Automotive Air Conditioning Forum

We've updated our forums!
Click here to visit the new forum

Archive Home

Copyright © 2016 Arizona Mobile Air Inc.