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85 TE -A/C + Heater issues


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  • Gold FFM

Thanks @Andyww and @910Esprit

I've now located that diagram (thx) - nowhere near any of the other a/c stuff in my manual 😡

pulley/tensioner missing 😞   

I'll have to get a good look under the front of the engine bay to figure out where all this kit fixes and how to run the pipework through. ....

Also, no idea of where the receiver drier should mount as nothing seems obvious (yet!) Another close inspection required ..

At least I know now that I need a new evaporator as well as hoses/fixings etc. and also a tensioner and pulley  - so that will have to be done with fixing the heater matrix.

Rhetorical question - why does anyone chop the little pipe ends on the side of the evaporator? What a waste of time/effort.

Cheers

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22 hours ago, Andyww said:

Evaporator.

Hi Andy. Is that indeed the evaporator? I've got both my S2 main casing plus one pulled from a '95 S4S wreck, and they are highly similar with the evaporator certainly located within the entry space on the S2. Photo attached for reference.

Is it perhaps instead that the PO fitted a cabin air filter into the boot plenum?   

IMG_2900.JPG

I may have got the wrong end of the stick here, thinking the photo showing cut cooling tubes to be of the condenser.

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16 minutes ago, drdoom said:

 

 

I may have got the wrong end of the stick here, thinking the photo showing cut cooling tubes to be of the condenser.

Thats why I asked where the picture was taken but apparently in the front plenum intake not the front rad tray where the condener would be.

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  • Gold FFM

So if I have this right -  your image shows what I would class as the Evaporator. This is the same part number from S2 Esprit and I believe was also used in S-Esprits too. (S4/S4s)

There are 2 versions - one for RHD and one for LHD. Yours have pipeworks connected - mine has been massacred for some reason.

These appear to be made of Unobtainium - and if found could be circa USD$400-800 a piece

The condenser is at the front of car near the oil cooler/radiator etc.

HTH

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Thats correct.

Lotusbits had several evaporators but thats going back a few years, they might no longer have any. They didnt have any tensioner pulleys.
You might be able to fit an alternative evaporator into the casing.

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receiver drier stands up rather awkwardly behind right hand headlamp pod.   If you look at pictures of Esprit front compartments, you can see it fairly easily (on AC models!).    They are pretty generic.

Do I recall tensioner is a Ford part?  But in the grand scheme of things, should not be too tricky to fabricate.  

 

 

   

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  • 3 weeks later...
  • Gold FFM

I still haven't fully committed myself (sic) to re-installing the AC, however - in doing some research I could do with a few pointers ... these are not in any particular order 

How do I calculate :

  1. Size of a replacement (non-original) compressor for suitability - is this based on capacity or just fittings?
  2. Cooling requirement (capacity, or some other criteria)
  3. Condenser size
  4. Evaporator size

Thanks,

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1.  Assuming you have the original brackets, that determines the style of compressor.   The other most important thing is that it is R134A compatible (assuming that's the gas you plan to use).  That in turn means that it will almost certainly have 'o ring' style fittings.   As you need new hoses, the actual choice of fittings is not crucial.   As the cab on an Esprit is small, a tip is to look for NOS compressors from tractors/plant, these are typically smaller than the original SD508, but have the same bolt spacing and still provide more than enough cooling..   Just make sure it is R134A, 12V and spins in the correct direction.  There's one on Ebay at the moment at £85, which looks a possibility.

2.  Not sure what you mean?   However, as above, an Esprit cabin is small, so a small 5 piston compressor will be fine.  IMHO the original SD508, used in many large American saloon cars! is way overspecced.

3.  R134A is less efficient than R12, so theoretically could need a larger condenser.  However, others on here use R134A with original size compressor and condenser without issue.  However, another reason I used a smaller compressor was to increase the ration of the original condenser to compressor.   I'd just use anything that fits, which is a similar size to original.

4.  Cant advise on that, but I would have thought the constraint would be whatever fits in the heater unit.   

 

   

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This is the condenser I used. Its a parallel-flow unit which is more efficient than the original heavy brass serpentine unit:

Steve is right, the Esprit systems were over-specced. Its true that they had to deal with weather in California for example which places a far higher demand but UK/Europe cars could have used a smaller system. I have an idea that someone at Lotus used a formula based on glass area, the Esprit does have a big screen but does not have much air volume to cool.
Especially crazy is the design on later Esprits which used two condensers connected in parallel with plumbing. No idea why they did that.

I also re-wired my fans with a second fan relay so that when the AC is on, only the two fans which blow over this condenser come on, not all three fans. That also spread the load of the fans over 2 relays.

If you wanted to fit a third-party evaporator you could look through the Delphi or other such suppliers web catalog which has dimensions then find one on Ebay, from another car. It would mean measuring the aperture in the heater casing first.

 

SSP022299.JPG

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Concur with Steve and Andy on points made. It does seem clear Lotus overshot the mark on cooling whilst perhaps leaving room to improve on airflow distribution, thinking of the instruments pod vent known to freeze one's knuckles. It's yet to be tested but I've assembled my system with compact Sanden SD7-B10 equivalent compressor, evaporator from Honda Odyssey aft cabin system, and the largest condensor found to fit in the space allocated ahead of the radiator. The condensor is native to Freightliner long-haul transport trucks common in N. America.

One technical point made clear in my researching the matter is to use the largest condensor that may be fitted. Others' postings in relevant threads on TLF over the years indicate a smaller compressor is entirely viable, as is R134a refrigerant. The smaller compressor should be a rather easy adaptation, given suitably located ports, the alternate condensor as well. Adapting an alternative evaporator will be somewhat more of a chore, but one may relieve the car of some 5 - 10 lbs of weight in going from the vintage copper tube/fin type to a contemporary aluminium plate style.

Cheers

IMG_2900.JPG

54983_ODYSSEY_REAR_10.jpg

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