air conditioning renew

deQuincey

deQuincey

Quousque tandem...?
Site Donor
Messages
8,877
Reaction score
2,775
Location
BIO - 43°15'46.5"N 2°56'03.7"W
so a new project comes,

as my car was originally sold in paris (1971), but later went to south sunny spain (1974), and odd air conditioning system was fitted somewhere and in some undetermined moment

when going through all the previous jobs in order to reach a driveable satisfactory condition i removed the front condenser and the tubes and the york compressor too

my intention is to refit a reliable system, so no doubts i will fit the more modern bosch compressor, but being my evaporator pretty odd i am considering a complete renovation
 
Last edited:
first a question

i am seriously considering using the complete ac system from an e28 donor car, see it here

to my eye the interior evaporator seems very similar to the original evaporator of the right e9 AC system



a detailed photo of the evaporator:



i will be using this support bracket for the compressor that attaches perfectly to the M30 (I guess)


i wonder if someone has done this before using exactly this system
 
Last edited:
not sure about the evaporator, but definitely get a new parallel flow condensor. It will greatly improve performance over the old inefficient one.
 
DeQ:
If possible where you are, you must get a copy of Rob Siegel's "Memoirs of a Hack Mechanic." It has an indispensable section on AC rehab/installation for E9s, along with a slew of other useful and entertaining stuff about E9s (and 2002s.)
 
deQ - I'm finally getting the AC operable in my car this week after having most of it installed at the time of the resto but not really needing it here in SF. Regarding the E28 system, I'm using a (what else for me?) modified version, but the original compressor that came with my S38, which has got to be the same one from the E28 & E34 run or with small variations, is sitting right where it always say and works fine. I put an in-line evaporator mounted on the passenger fender and bought a modern condenser for improved performance. The worst part of the system now appears to be the hamster wheel fans inside the car, but at least it will likely work acceptably.

The car is at the AC shop for R134 right now but I could take pics when I get it back if you're interested.

-John
 
rb1971 said:
deQ - I'm finally getting the AC operable in my car this week after having most of it installed at the time of the resto but not really needing it here in SF. Regarding the E28 system, I'm using a (what else for me?) modified version, but the original compressor that came with my S38, which has got to be the same one from the E28 & E34 run or with small variations, is sitting right where it always say and works fine. I put an in-line evaporator mounted on the passenger fender and bought a modern condenser for improved performance. The worst part of the system now appears to be the hamster wheel fans inside the car, but at least it will likely work acceptably.

The car is at the AC shop for R134 right now but I could take pics when I get it back if you're interested.

-John
Click to expand...

yes, please john
thanks
 
FYI- dequincey

I rebuilt my system over a year ago.
I had to get a new expansion valve (which you can get online at places Rob mentions) as that is why it wouldn't cool.
Very much a pain to get to but while I had the evaporator out I had it pressure tested. It was ok.
Bought a parallel flow condenser from Nostaglia Air I beleive. I bought one that was close to the correct size and then made some brackets to hold it in place.

I had a Sanden style compressor and it was working but this summer on the way home from Colorado the compressor was making some pretty bad noises. It finally purged after I got home and lost the Freon.

New Sanden compressor using 134a.
So driving today. 80 degrees in Atlanta. 65 mph and the temp at the air output grill was cycling from 42 to 50 as the compressor turned off and on like it is supposed to do. This was measured with a stem type AC thermometer stuck in the grill.
So they will get cold.

I would recommend going to o-ring type connections. I did not and have had leaks I've had to fix.

With all the air output in the center it's not going to get better than this.
Yes, an E28 system might work but basically it the same parts we have in the coupes.
HTH
Gary
 
thank you gary, some questions below
m5bb said:
FYI- dequincey

I rebuilt my system over a year ago.
I had to get a new expansion valve (which you can get online at places Rob mentions) as that is why it wouldn't cool.
Very much a pain to get to but while I had the evaporator out I had it pressure tested. It was ok.

pressure test of evaporator and compressor worries, as the shop said they wouldnt do, and i can guess it is only to test air tightness by using compressed air and puting the evap or compressor in a water basin or similar, right ?

Bought a parallel flow condenser from Nostaglia Air I beleive. I bought one that was close to the correct size and then made some brackets to hold it in place.

I had a Sanden style compressor and it was working but this summer on the way home from Colorado the compressor was making some pretty bad noises. It finally purged after I got home and lost the Freon.

New Sanden compressor using 134a.
how can i tell if a certain compressor is for R12 or for 134a,...

So driving today. 80 degrees in Atlanta. 65 mph and the temp at the air output grill was cycling from 42 to 50 as the compressor turned off and on like it is supposed to do. This was measured with a stem type AC thermometer stuck in the grill.
So they will get cold.

I would recommend going to o-ring type connections. I did not and have had leaks I've had to fix.

With all the air output in the center it's not going to get better than this.
Yes, an E28 system might work but basically it the same parts we have in the coupes.


HTH
Gary
Click to expand...


thanks
 
If reusing old parts/compressors that might have run R12 before and thus might have mineral oil residues, there are two things on can do:

1. Clean out all traces of the old oil with a cleaning agent (brake cleaner might do if no proper other agent is available).

or, alternatively:

2. Drain out old oil as best as possible and then use only synthetic (PAG) A/C oil with the R134.

Reason beeing: the native oil of R12 was mineral. The native oil of R134 is esther. The R134 does not pick up and transport the mineral oil and it can get clunked up and mixed wiht the esther oil hindering propper lubrication. Since PAG works well with R134 and does not mix with the old mineral oil, it´s the best oil to use in old R12 systems that have been converted but never fully cleaned.

Make sure you change an expansion valve for R134 though, otherwise you loose a lot in performance.

Actually A/C is not very comlplicated. Certainly not complicated when compared to, say a Zenith carb. I´ve overhauled the A/C on my Jag and converted it to R134 myself successfully. The only thing that requires tools not normally available to the home mechanic is the final evaporation and filling with R134 (can be done at home as well but getting a good vac pump and gauges and lines and all that is more expensive than having a shop do it (I paid 95€ for the evap and fill up - couldn´t have done it myself for that money)).
 
deQuincey said:
thank you gary, some questions below




thanks
Click to expand...

Hey, I think all they do with the evaporator is put some air pressure in it and stick it in a tub of water.
All you can do with compressors is put them in and see if they work.
Now you might be able to spin the shaft and tell if the bearings were bad.

I think most new compressors are marked for 134. In the US you can't buy a replacement R12 compressor. When I had to get one for the M5 I bought one from BMW $$$ but it was marked for 134 only and that was the only way my AC man at the time would guarantee anything.
Remember the hose connections for putting in Freon are exclusive to the type. R12 hoses only fit R12 couplers. Same for 134. That way they don't get mixed together. Like Steve said different type of oils.
Modern evaporators are better at the transfer of the cool into the air for the system. If we wanted that we would have to have a custom evaporator made.

Most AC systems are designed to get a 25 Degree drop in air temp from outside air temp. Houses as well.
So today I was getting a 38 degree drop which is great.
Earlier in the year my switch that controls the temp was not working and the AC evap would freeze up. Literally have ice all over it.
The temp switch allows the compressor to cycle off and on so it won't freeze up. Had the same problem with the M5 a few years ago.
HTH,
Gary
 
To chime in on some of these questions:

To chime in on some of these questions:

--My understanding is that there aren't "R12 compressors" and "R134a compressors." Any compressor will work with either refrigerant. But you need to use the correct oil for the refrigerant. In the past, this was mineral oil for R12 and Pag oil for R134a. These days, ester oil is commonly used for R12 systems that have been retrofitted for R134a so any trace R12 doesn't react chemically with Pag oil and produce corrosive by-products.

--Historically, for the most part, R12 systems used flare fittings and R134a systems used o-ring fittings, but there's nothing to prevent you from using o-ring fittings on an R12 system. I do it all the time. I use a Sanden-style compressor with o-ring fittings, put mineral oil in it, and charge the system up with R12.

--If you're updating an old system in an E9, it makes sense to use a compressor with o-ring fittings, a receiver/dryer with o-ring fittings, and a parallel flow condenser with o-ring fittings. Use the largest paralle flow condenser you can physically stuff into the nose. Through trial and error, in my opinion, the biggest you can fit is 16x22.

--The only component that must still use flare fittings is the evaporator assembly, as you're stuck with the flares that are on it. I've sometimes used flare to o-ring converters, then made every single hose using o-ring fittings, but there's no getting around the flares on the evap. DeQuincey, are the fittings on the E28 flare or o-ring?

I explain most of this in great and gory detail in the a/c chapter in my book.

I posted a long thread a few months back about the bracket. If you're using either of the original wing-cell compressors, you can/should use their original brackets. If you're using a Sanden-style compressor, you have to look hard to find a new old stock retrofit bracket. They're getting very hard to find.

-Rob
 
You can buy an R12 compressor, I did off eBay, new, oiled up and ready to go. Will frost the family jewels off :p

m5bb said:
I think most new compressors are marked for 134. In the US you can't buy a replacement R12 compressor.
Click to expand...
 
triple core radiator questions

to complete the setup, and in order to improve the engine cooling I am planing a triple core radiator modification, this means to change the core of the radiator by a triple one which thickness excedes in 10mm the old one,

the process is interesting, the old radiator is dissasembled, the two lateral cavities are kept and repaired and the old core (40mm thickness) is replaced by a Brand new Taylor made one (50 mm thickness)

and this creates and issue with the renewed fan in the new visco setup

photo of actual setup before triple core:



schematics:




the old visco with 5 blade fan was replaced long time ago by the new setup from walloth&nexch that inlcuded 9 blade black fan and new visco plus conical adapter

that setup gives you 10 mm gap from fan blades to the old radiator (doublé core)

so now that i am planning to increase radiator thickness in that exact ammount (10mm), fan blades will be in contact with radiator surface, thus i must plan a solution to move the fan 10mm backwards

can anyone help with his experience on this topic ?

exact questions:

will the triple core radiator interfere with the fan setup ?

is there any solution that you know, using other visco, support, or fan ?
 
Last edited:
The newer pump doesn't use the cone, it has a bolt that spins on where the cone was and gives more clearance, recommended by sfdon.
 
HB Chris said:
The newer pump doesn't use the cone, it has a bolt that spins on where the cone was and gives more clearance, recommended by sfdon.
Click to expand...

more on that please, i am using a doublé pulley as my steering pump needs it, the pulley has four holes that coincide with the cone, how can i complete my puzzle with that newer wáter pump ?
 
You must log in or register to reply here.
Back
Top