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1968 Replace A/C / heater box or fan for greater airflow?

tomcwarren

Well-known member
Joined
Apr 9, 2008
Messages
126
Location
Phoenix, AZ (Ahwatukee)
Folks,

I've got factory A/C in my CS (integrated, thru-the-dash, not underdash), with a newer Sanden compressor and R134a. Seems to work OK, but not great in 113 degree Arizona heat. I'd like to drive my CS more in the summer, but it gets unbearable pretty quick. :tongue:

I've had the refrigerant levels, etc. checked and all seems well. One thing I noticed is that the air flow from the dash and lower left/right vents isn't very strong, even on the highest fan setting.

Here's my thought/question - has anyone looked into replacing the A/C / heater box/fan assembly with a more-efficient assembly from Old Air or Classic Air or Vintage Air to improve cooling and airflow? I assume a newer, better-engineered unit ('power pack' according to Old Air's website) would cool and flow better, but I'd like some anecdotal experience first before calling 'em.

If anyone has done the complete install of one of these aftermarket systems, and has an opinion on whether the airflow/cooling is any better than a factory A/C install, that'd be helpful, too.

Thanks,

Tom
 

franklinair

Well-known member
Joined
Mar 1, 2007
Messages
4,741
You did the A/C system a big favor in replacing the old one lung compressor. R134 is OK, but I believe R12 is better- but scarce & expen$ive.
I've removed the underdash unit (not a fun job), made sure all joints were as air tight as possible, to insure optimum air flow.
Then I adjusted the temp sensor on the evaporator to the coldest setting.
All this was done when I lived in FL (95+ temp & humidity) in a Black/Black '68 coupe. In ideal conditions it blew out cold air @ 40 degrees. In stop & go traffic, 50 degrees. (Your house A/C only blows @ 50/55 degrees.)

Neil
 

murf104

Well-known member
Joined
Feb 2, 2003
Messages
274
I feel it compelled to add to this. The 68 at our house is not the best cooling car around. The entire assembly underdash has been removed, resealed, cleaned and a new heater core. All doors are properly adjusted and all vac servos have the "full Stroke" operating. The low side pressure goes well into the mid twenties before the clutch will cycle out, and the clutch cycels in when the pressure gets in the high thirties. Water drains well from the evap housing also. The evap pressure tell me it is just about as cold at that point as it can be without freezing the condensation on the coils. However, the outlet temp is about 40 or so at best, not the finger numbeing 33 or 34 I had assumed would blow out the dash. I have r-12 in the system, did charge it with 134 but the temps in traffic were in the 50 to 55 range- cooled maybe just OK on the road with the r-134, so used the r 12 again and am still not satisfied with the outlet temp. Is this system just that poor? Anyone have any tips to get the outlet temp down to the point of being cool enough to make the car comfortable.?
 

franklinair

Well-known member
Joined
Mar 1, 2007
Messages
4,741
When I set the evap temp sensor to the lowest setting, mine put out air @ 40 degrees at the registers (using R-12, all gage pressures normal).

Neil
 
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tomcwarren

Well-known member
Joined
Apr 9, 2008
Messages
126
Location
Phoenix, AZ (Ahwatukee)
I was looking thru Classic Auto Air's excellent catalog (lots of good general A/C info in there), and noticed that they will rebuild your plenum/evap box and add their 'hi-performance' evaporator. I've requested a quote.

I also noticed that they claim the condensor is the most important factor in achieving a good cooling experience, and they have a 6-row upgraded condensor for sale as a direct replacement.

I'm thinking of doing the evap rebuild/upgrade, plus a new hi-perf condensor, swapping out the filter/dryer for a new one (recommended by CAA when opening the system), and seeing what I get then. Several hundred dollars, but worth it if I get better cooling. :rolleyes:

'Factory' catalog:
http://www.classicautoair.com/Catalog/FactoryCatalog.pdf

Tom
 

murf104

Well-known member
Joined
Feb 2, 2003
Messages
274
The condenser on my car is one from NPD. I think it was called a "6 pass" when it was purchased along with a new dryer. The condenser was missing from the car when I purchased it so have no basis for comparison.
 
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tomcwarren

Well-known member
Joined
Apr 9, 2008
Messages
126
Location
Phoenix, AZ (Ahwatukee)
Can you put a thermometer in the dash/lower dash vents and let us know what temp you see on max A/C?

I'm going to test mine later today to get a baseline before-and-after temp.

Tom
 

franklinair

Well-known member
Joined
Mar 1, 2007
Messages
4,741
That's exactly what I keep in the register in my car, only I place it in the center (dash) outlet just for ease of visibility. The A/C thermometers are a common tool available from auto tool suppliers. It's about 6" long, diameter of a pencil. I think I got mine @ NAPA years ago.

Neil
 
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