Air/con retrofit; a long story

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alan s
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Air/con retrofit; a long story

Post by alan s » 26 Jan 2005, 03:30

Just thought I'd post this here for a bit of light entertainment.
It's a copy of something I wrote up on a board over here so some things refer to Australia.
I'm sure Tom Sheppherd and David will get a few good laughs out of it; kinda de javu.
<center>******************************************************</center>
We often see postings asking questions about private imports as regards how much they'll cost and what are the pitfalls, but few if any ever mention the air/con side of things.
Many of the cars that would qualify as a Private Import were made in an era when air/con was a rarely taken up option in the Northern Hemisphere whereas in many cases it was looked upon as either standard equipment or a favoured option out here. This is where we come into it.
As most know, my son bought a series one 16V, 1988 model that was a fire damaged car from a public auction. He found that a car with 130K miles on the clock isn't exactly in a suitable condition to be used at the sprints, hence it had to have an engine rebuild. About this time, a second (series 2) came on the market also burnt out, so it was bought predominantly for air/con parts.
First job was to swap over the crankcase as the air/con cars have an alloy sump complete with all the mountings for the compressor etc, whereas the series one, without, has a pressed steel sump, so he killed two birds with the one stone by rebuilding the engine and swapping the sump at the same time. The rest of the air/con was taken out and left lying on the ground, sealed off of course, whilst a variety of jobs were done, when somebody (no, not me) drove around late one afternoon and......drove over the bloody lot of it!!! Result, condensor stuffed, fans mangled. Not impressed. Engine rebuild job was completed and the car used without the air/con. As we live in a very hot part of the countryside where temps far exceed weather bureau figures, mid 30s and 85%+ humidity being the rule more than the exception, and this car is used as a work as well as a pleasure vehicle, the air/con is almost essential; enter a friend with a Trs and we are offered the air/con out of it. After dismantling almost the entire car, we get it all out.
Where to start? Out with the dashboard, completely out of the car. Out with the heater matrix assembly and underbonnet box. Whoops; there are two fans in the air/con car and ducts that lead through the firewall; Whoops again. The series one didn't have either, so out with the duct, sit it in, mark and cut penetrations through the firewall in exactly the same positions as the series two. Another whoops; the bolts to afix these to are also not there, so a case of mark, drill and weld to hold captive. Popped it in; it all fits.....phew!!!
Time to set up the air box near the evaporator/matrix region. Series one box hasn't enough space for an evaporator and series two has been on fire so would give off toxins....bugger! Look at the one from the Trs but (naturally) it was slightly different. A bit of ingenuity and modding and we have ourselves an airbox...................................<font size="1">(to be continued)</font id="size1">
Plans at this stage are to attach the air/con to the MoTeC so that the fan cuts out above 80KPH and the compressor chops off above possibly 5500 rpm so as to have minimal effect on available power when needed (both could have overriding switches if necessary). All the foam sealer has been either destroyed or perished so this is all getting replaced so as to seal out as much non refrigerated air as possible. An engineer friend who was visiting last night, saw the entire system and reckons it's twice as big as the one in his De Tomaso Pantera and reckons it should be capable of freezing everybody to death (something we BX owners already knew) and was more than a bit impressed with the engineering load sizing etc of the entire system.
As a post-script, it was mentioned in passing also, that he may add to it a coolbox in the boot to keep drinks and food cold both on trips and when he's working so I just hope in the process of going overkill he doesn't lose the advantages of the air/con system itself, although it would be quite feasible to isolate the cold box from the rest of the system when not in use.
I have a feeling that sooner or later, someone in the media will suddenly have the penny drop about what he has here; a performance car used as a work hack and shopping trolley during the week and doing up to 700 miles a week that is used some weekends at sprints and hillclimbs and has a programmable EMS fitted, air/con and is a one off in the country to our knowledge, so it putts around at work and one night remapping the ECU, swapping exhausts and a few other odds and sods and it's a track car showing good results for the minimum of work that's been done. It reminds me of Clark Kent and Superman or better still; Jekyll & Hyde.
I'll do another posting when the job is complete.
Alan S

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Post by alan s » 27 Jan 2005, 18:26

....................................(continued)
right, now we get to fitting the "new" condensor that has come from a 16Trs....too big......bugger... it seems that whilst a 16Trs may be only a 1.6 litre motor and a 16V a 1.9 twin cam, the condensor is only a fraction of the size, no doubts the engine revs have some bearing on this and the fact is that on a Trs the radiator & condensor both fit on the engine side of the front under bonnet crossmember so there's more room to play; not so on a 16V with the plenum sitting almost against the radiator and the mounts for the condensor fitted on the outside of it. Thought a Pug Mi16 may fit but no go there either. The 16V is 520 X 280 whilst the Pug goes 580 so it's too long
The fans may be another story as the mounts seem larger and more substantial on the ones from the Trs but we'll cross that hurdle when we come to it. That's possibly in the next "episode."
Alan S

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Post by alan s » 28 Jan 2005, 15:57

Righto, next hurdle to cross.
The 16V condensor is:- 520 X 280 X 21 thick and as we've seen, this is not interchangeable with a Pug Mi16.
It looks as though we've straightened the original one, but in the process, we've enquired about a new one...........A$1200....suggested he bend over & grunt; no way in the World are they worth that; they'll die with it before we'll pay that price, if need be I'll get a custom built one, unless I can find a similar one at a more reasonable price.
Guess what? An early Subaru Leone condensor is 534 X 285 X 22 same connections on the correct (same) side and is A$162 (Subaru Part number CN1196)
Fittings should be no sweat as they are pop rivetted on, so carefully drill out and re-rivet and all is well. Hopefully it won't get to that, but if it does...............$162 I can understand. $1200 is plain bull$#!+ for a tiny little thing like a baby radiator...The Suby one "may" need an e;bow fitting or a hose with a right angled end on it, but hey, I can live with that.
I'll keep you posted and see what the next session brings.
Alan S

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Post by tomsheppard » 29 Jan 2005, 04:19

Deja vu again, or have I already said that? Stick with it Alan, I am reminded of last spring's efforts but they were worth it!

alan s
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Post by alan s » 30 Jan 2005, 03:18

He had an early Sabbath yesterday, so not a real lot of progress, however, one interesting one did come up that nobody probably ever thinks of; he grabbed the front wiring harness off the donor car and ran it in the loom on his.
Now he has two male plugs and no female counterparts. Some wires are in what is obviously a standard loom, whilst others must be exclusively for the air/con oe export models. Judging on the size (as in gauge) of the wire on these plugs, they attach to a sensor of some description so we're still searching.
Another interesting feature too is that in the non air/con car, a hole has to be cut just behind one headlight about 75mm diameter to accomodate the filter dryer.
Compressor fitting was no hassle due to the fact that the alloy sump off the donor car was in place.
After admiring the performance of the BX air/con all these years we think we may have an explanation for its outstanding efficiency; well balanced system fed through a fully insulated ducting (plastic) and massive cfm capacity from the fans both inside and out.
Alan S

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Post by alan s » 31 Jan 2005, 15:58

Right; test time. Evacuate system, get all the air out and find the switch on top of the receiver dryer has been bridged out.....Ohh boy....bloody cowboys!!! The system was short of gas so some hillbilly air/con "specialist" has discovered a way to make it G(O); just hope he hasn't stuffed something in the process.
Time to resort to the "book" for finer details; new "O" rings are to be fitted prior to commissioning. These need to be 'High grade Neoprene' or 'HNBR' "O" rings. New dryer on order from Repco; cost A$65 has to be the type that contains HX9 Desiccant. POE or PAG lubricant to be added to compressor whilst system is under vacuum after compressor has been removed, and old Suniso (R12) lubricant drained out. New 134a ports to be fitted over R-12 (schraeder types).
Basic tests show no power to the solenoid; bugger!! at least now we know why there's a plug running free leading to nowhere. Trace circuits, find the supply of power to the relay to the clutch is piggy backed from the ignition coil.
Waiting for the balance of "O" rings to arrive along with the receiver/dryer. Former associate in the refrigeration field has been invited over in a few days with the request to bring his work van.......loads of booze in the fridge getting cold; keeps 'em happy and occupied while you "raid" the work van for 2 stage vac pump, gas charging station and bottle of 134.
Next step, all going well, is cold air followed by the big road test in approx 40 degree temps; can hardly wait.
Alan S

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Post by tomsheppard » 01 Feb 2005, 01:45

Aircon wiring is a black art as Citroen have lots of different ways of doing it.
If you have a positive side switched engine fan, Instructions on wiring have been posted on this forum, round about last June/July by yours truly. Good luck and keep cool!

alan s
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Post by alan s » 02 Feb 2005, 03:17

Tom,
Is this the one you're referring to?
I remember reading it at the time, but amazing how much more sense it makes when you've actually disembowelled the car isn't it?
http://www.andyspares.com/discussionfor ... complished
Another interesting link that Bernie posted on the air con forum is this;
http://www.sanden.com/support/pdf/sd7servicemanual.pdf
It takes a lot of the myths out of car air con and is a brilliant reference point. I've printed myself a hard copy of that so that I have this and other info here for future reference if anyone needs it.
Another interesting snippet too, is that one of the evaporators we used had a new TX fitted to it and it was shown as an "M 95" so if anyone is looking to replace the TX (which have a habit of leaking from the area near the bellows, the type you need is an
"Eaton block valve" Type N95 (R134a) which should convert to Eaton part number 329-439 or as a generic part number NG00001
Alan S

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Post by tomsheppard » 03 Feb 2005, 03:15

Alan, I found it. topic is 8401 from 26 th July last year entitled Late model BX aircon wiring. Still don't know how to set up the link to the topic as you do so I used the search facility under my name keywords BX aircon Wiring. That'll get ya there.

alan s
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Post by alan s » 03 Feb 2005, 04:46

The Epilogue:
Having the entire system now installed, vacuum drawn on and left overnight, a check of the gauges reveals no leaks nor moisture.
Fridgie mate duly arrives and special type of oil is added to the already drained compressor. The two stage vacuum pump is then connected to the system for a final evacuation. The idea of the pumping besides removing any air or residual gases is to also reduce the boiling point of any moisture and draw it out as vapour (kind of reverse principle to a radiator cap/cooling system where they increase pressure and thereby increase the boiling point).
Remove fancy caps on the charging valves; why are they there? so anyone following you on the job knows it has R134a in it and not R12, and charge system. Runs, and back & high side pressures are acceptable.
Test drive time: Take off and head for the open road. Noticeable reduction in power; not excessive but as compared to the TZi a definite feel of power drop off when the compressor comes into circuit, possibly caused by the fact that for reasons best known to themselves, the area of condensor is markedly less on a 16V than on other models and as we discovered in the conversion, they can't be interchanged due to the physical size of the enginecausing the condensor to be fitted on the opposite side of the upper front crossmember on the 16V; something we "may" have to address in the future, even going as far as getting a custom condensor made up if need be.
Temperature off the coil not as good as was expected possibly due we initially think by the smaller surface area of the condensor. However given a few runs and this seems to be on the improve and this is attributed to the fact that the oil needs to circulate in the system to a degree and due to being exposed, drained and refitted, this may be still sorting itself out or alternatively, there could be a minute particle of moisture that by now may be where it belongs; caught up in the dryer.
Final test finds that the temperature is now acceptable (so more likely than not the moisture angle could be the answer, given the amount of exposure the system has had), so it's now time to refit gloveboxes, rear shelves and anything else that needed to be removed in the process of the installation................but wait; Remember I made the comment about this guy being a bit "overkill"?............here we go:
Instead of just leaving this as a standard unit doing all the things a standard air/con will do, he has to go that one step further, so into his MoTeC he programs a set up whereby at 80% throttle position, the compressor cuts out. This eliminates the load of the compressor from the engine when overtaking or going up steep hills. When he backs off to around 38%, it reactivates the fans and then starts the compressor. The same applies when the thrmostat cuts back in during a normal running cycle. The fans cut in, run for about 2 or 3 seconds and then in comes the compressor so that there's a time lag to allow the fans to remove the initial radiated heat from the condensor and it works well.
I had seen a similar system used years ago by installing a micro switch to the accelerator pedal; this brings the same idea into the 21st Century.
Just a final note on the "O" rings used, which are of the type previously mentioned (ie) High grade neoprene.
To identify them from the norm, they are a grassy green colour. Normal black "O" rings can be used and these must be of a high grade also, but, it seems that the oils used and some of the refrigerants, will attck them, so if you're going to go to this amount of trouble, might as well do it right and hence do it once.
Not an impossible job to do, but not one I'd tackle alone as you need someone else there to watch your every move and to give both of you someone to bounce ideas off.
Anyone intending doing such a project (best description I can come up with) had better be prepared to do the largest percentage of the work themselves and swat up on the basics of refrigeration before you start as it's not the kind of work that allows you to learn by your mistakes. If a tradesman were to be employed to do the job we just did, I'd be surprised if the job could be done for less than A$3000 plus parts (working on these guys charging A$80 an hour). The most practical way is to use the parts from a scrapped car and the best way if possible would be to have the cars side by side so as one part came off the wreck, it could go onto the car and wiring could be traced for refitting. The easiest of these conversions of course would be to be fitting to a car that was originally designed for air/con which may or may not be the case with the series two. This definitely does not apply to the series one where holes had to be cut into firewalls and inner guard panels to fit fans and dryers.
If you decide to give it a try; good luck, be methodical, clean and thorough.
Alan S

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Post by tomsheppard » 03 Feb 2005, 20:43

Or just read this forum. Alan very kindly took me through this stage by stage last year!
I must get the topic numbers off to Jon so that we can archive all this stuff for the inquisitive.

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Post by bernie » 03 Feb 2005, 21:00

Sounds like a piece of cake,[:D] I don't know why you're making so much fuss Alan.[;)][;)]
You can get the same effect by standing next to a fridge with the door open[8D][8D][8D]

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Post by Oscar Too » 03 Feb 2005, 21:45

I don't know how you Aussies stand all that heat. [:)] Christ we had a couple of days over 15 deg Cent here last summer and the train tracks were buckling, people were falling over in the streets, the country pretty well shut down as everyone took shelter in their cellars from the warmwave. [:)]
Give me the rain and wind any day. You can't beat that flop-swish sound from a windscreen wiper that's on its way out, squinting through the rain - headlight dazzle, or the sudden lurch as a gust of wind blows your BX across the road. Then you know it's summer in England and the best possible weather.

alan s
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Post by alan s » 04 Feb 2005, 03:31

Well at present Oscar, there's a lot thinking of emigrating to the Northern Hemisphere I think.
I was e-mailing a friend over your way the other morning at 6am and it was 28 degrees C THEN. Try sleeping in that for a while and I agree, the thoughts of rain (something that's almost a collectors item where I am; place is parched and barren) and cold is quite appealing. Probably something to do with green grass (what's that look like) on the other side of the fence.
<b>For the FINAL final word on this air con job:-</b>
The car hit the road and the air was cold; bloody cold!! This was at the point where it enters the car. High side temp was high around the condensor and there was condensation forming on the return line near the firewall and on it's way back towards the compressor. All the symptoms of overcharging, how could that be? Kept on driving, stopping, checking the system as we went and then the vent switch was turned to "Fresh air intake" which is a big nono on air/con cars in Oz due to the high humidity which can cause them to ice up the evaporator in minutes if not seconds. I notice a roaring noise coming from where the intake of it is and put my hand there; it feels like air coming <b>out</b> of it!
Grab a piece of paper and test; no definitely going in....what tha??
On closer inspection, it seems that when the fans and cowls were out of the car, the bushes were oiled due to a mechanical feeling tightness caused by dry bronze bushes, so to oil, the fans were removed from the shaft (mixed up unbeknowns to us) and when refitted, went in with the blowers back to front. It seems that the rotation of the left hand fan and the right hand one are opposite and the giveaway noise and feeling of blowing instead of sucking was caused by the air getting "messy" rather than following a pattern. Mongrel of a job, but had to be done, so out with both fans and all the gear that needs to come out to access it, swap the fans (they're a barrel type not a prop fan) and reassemble.
Previously, due to the lack of air pattern and hence duct velocity, we ended up with a sensation that was quite weird; we were ice cold from about the chest down whilst from there up, almost as though there was a pencil line drawn across our bodies, it was sweltering hot. Now we all feel much more comfortable and rather than just being a source of cold air blown in the general direction of the cars occupants, we do have air condtioning; the entire car now comes down to a liveable temperature. So far he hasn't embarked on any long trips, but with the heatwave conditions showing no signs of abating for another couple of months, I'm sure it will get plenty of use.
Alan S
PS. Apologies for the long and what may seem over detailed descriptions on this, but as I have pointed out, this is a long, detailed but not impossible job to do and hopefully for anyone who has air/con or intends fitting it, this should be of majr assistance in both installation, commissioning and if need be troubleshooting on completion.

Dave Bamber
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Post by Dave Bamber » 04 Feb 2005, 04:09

No apologies Alan, it's a very informative piece. I'd like to do the same to my new BX as the A/C is what I will miss the most from the Berlingo, but I feel the chances of finding a dead BX over here with A/C are a bit thin.