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Help with 240 Air Conditioning

Sinbad the Sailor

Sinbad the Sailor

Master Destructor
Joined
Sep 22, 2003
Location
San Jose, CA
I am looking for input on how to go about getting good AC for my 240. I know that everyone ditches theirs for the performance benefits but I am looking for creature comforts here.

I am planning on pulling the entire AC system from a 91-93 240 with the system already converted to r134, but I am wondering what I could do without pulling? I am going to go with custom AC lines so that I can route them where I want them to go. So does that mean I only need the condenser, receiver/dryer, evaporator, compressor and then measure and have the lines made.

Am I over simplifying here? This doesn't seem that hard to me. Do the lines have to be hard lines or can I have them made at a hose shop?

Any input would be appreciated.

Would I even need to use parts from a 240? Apart from the compressor and evaporator could I just find the right size parts and get the hoses made to fit? Or would it be best to keep the same system?
 
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I'm assuming you have a pre-92 or 91 system, which has the smaller evaporator. FCP sells a retrofit kit with all the seals, r134 evaporator (which is just larger since r134 isn't as efficient) and a new dryer. Check out this site for all the hoses and fittings that you'll need:

http://www.ackits.com/

I did custom lines on my 242 and got everything from them. They also have new compressors for ours, which turn out to be fairly common compressors, so they're not too expensive. Any A/C shop should have the tools to crimp the fittings on the line. Just order the right hose and the right fittings you'll need, cut them to length and mark the fitting orientation. But unless you're changing to a new condensor (which is what I did) then I don't see why you need custom lines. What's wrong with the factory routing?
 
I don't like having that line running over the valve cover and I have some other plans for the engine bay that don't include having it look stock. And I am going to have to find a condenser that will fit where I want it to.

Thanks for the info.

1982 244t BTW.
 
Hydrocarbon refrigerant is the most efficient with a small issue of flammability.

r-12 is second with about 5-10% drop in performance.

r-234a is cheap now but is going up too, about 25-35% drop in performance compared to r-12.

The main goal in any A/C system is keeping the condenser temperature as close to the ambient temperature as possible, the bigger the better and a electric fan helps at idle.

The evaporator should be held below the dew point temperature to remove humidity from the air and be able to remove enough heat to maintain cabin temperature.

Good hoses should not purge refrigerant quickly and seals and oil should be compatible.
 
Moxy, you seem well schooled on AC, as you would be living where you do.

I have searched for AC threads and found that each one may have one or two nuggets of wisdom, but as a newby to AC I have been having a hard time putting the whole picture together. Is there one source- a book, or online resource, that gives an overview of how AC works, how the components each work, and how to make it work right? I am in a similar position to Sinbad- having a 240 with non-functioning OEM AC and wanting to convert it and get the best from it.
 
BabyBlue240 said:
r134 evaporator (which is just larger since r134 isn't as efficient)
Click to expand...

Volvo went to the larger evaporator in 91, two years before they switched to r134a. The evap was changed because the old one wasn't doing the job even with r12. Regardless of what refrigerant you choose I would use the enlarged evap and the later condenser, plus an efan.

I am still in the planning stages of dropping the entire 93 240 AC system into my 242T, but haven't made much progress lately besides gathering all the parts. Too many other things to do. I found the Volvo Climate Control greenbook extremely useful in researching the conversion.
 
Automobile air conditioning is quite simple in principal. It moves heat energy from a low temperature source, evaporator, to a higher temperature point, condenser. The components of the system are very high tolerance though, more than anything else on a car.

The fundamental equation that determines its efficiency is the difference between these two points, evaporator and condenser. The greater the difference of temperature between the two points the less the efficiency. Roughly if you double the temperature difference the efficiency goes down four or more fold. Since the evaporator has to be cold enough to remove heat and moisture from the cabin it must be maintained above freezing, 32F, and not much higher than 45F. That leaves the condenser the only point to modify so the goal here is to keep it as cool as possible.

The whole system must pump enough heat so the compressor has to be large enough to do it.

The cabin heat can be reduced by insulation and as in Phoenix the color of the car makes a huge difference.

The next biggest component to increase efficiency is the refrigerant as mentioned above.

Smaller adjustments can help as in the construction of the system itself but the above are by far the primary factors.
 
Harry Tuttle said:
So, when upgrading an older car, does that larger evaporator fit into the space previously occupied by the earlier one, or does the housing have to be changed?
Click to expand...

Indeed the later evaporator does fit into the same space. Back when fcpgroton had a website that actually worked :grrr:, one could look up the retrofit kit which included the larger evap core. From what I have read in my own planning process, some folks have had success in improving the efficiency from changing either the evap to the later model or changing to a modern parallel flow condenser (see ackits.com as mentioned prior)..

J
 
The newer condensers are more efficient then the copper tube and fin but careful using an old one as they cannot be flushed most of the time. The openings are very small in them and fill with debris that is difficult to remove.
 
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