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Old 02-19-2018, 03:41 PM   #1
RADustin
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Vintage Air in a Crewcab

Looking for people who have the vintage air gen IV units in their crew cabs, and how they like it.

A topic came up on one of the facebook groups about how it doesn't work well, so I was curious what the consensus was here. I live in New Orleans where it is very very humid and hot most of the year, so good AC performance in both cooling and dehumidification is important. Heat and defrost is a solid 3rd and 4th.

I'm currently tossing around ideas of vintage air or using my 2014 donor trucks ac unit. Either way the stock 1976 unit will not work for me as I need a clean firewall.

TIA
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Old 02-19-2018, 05:26 PM   #2
bluex
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Re: Vintage Air in a Crewcab

Which group? are they saying its not so good for a crew cab? I'm about 2 weeks away from ordering a kit for my regular cab so I wouldnt mind reading what they have to say.
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Old 02-19-2018, 05:30 PM   #3
RADustin
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Re: Vintage Air in a Crewcab

called 'squarebody crew cabs'

I wouldn't fret for a reg cab. my brothers vintage air in his '67 c10 will run you out very quickly. It is really good.

My concern is over the added volume/windows/heat input of a crewcab over a regular cab.
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Old 02-19-2018, 05:46 PM   #4
hatzie
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Re: Vintage Air in a Crewcab

The volume in a crew cab isn't much bigger than a fullsize four door sedan cabin. It might be the same volume.
Is the evaporator noticeably smaller than the stock Harrison unit?

Plenty of room for a huge condenser. I read somewhere the stock CK truck condenser was around 1/3 larger than it really needed to be.
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Old 02-19-2018, 06:25 PM   #5
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Re: Vintage Air in a Crewcab

I don't know about the components use with Vintage Air, but there are several choices for everything. Aftermarket, OEM or the bone yard find. One thing you will have to deal with is R134a. It has a smaller molecule that R12 and requires excellent seals and barrier hoses. One item some may not know, is the evolution of GM's A/C condensers over the years. While in the 70's, the tubes on the condenser look like you could roll a ball bearing from one end to the other. This was ok for getting rid of latent heat using R12. R134a actually carries more BTU's of heat energy per pound than R12. It just boils at a slightly higher temperature. This why the amount of R134a is way less in systems that use it. Here is what GM engineering did...they went to extruded aluminum serpentine condensers with small holes. Now in 2000, they went a step further and extrusion process allowed for tiny perfect uniform holes in a row of tubing. This greatly increased the removal of latent heat, making R134a systems even more efficient. Think of two systems, like front and rear, but one condenser. The photos attached below will show why. I cut one apart to get a good shot. This creates an issue; flush or replace? If you experience a compressor failure, you will have to replace the new style. If your in a bone yard hunting, look thru the grill at the condenser rows. If they are thinner than a book of matches, you have the new style.
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Old 02-19-2018, 07:18 PM   #6
ryanv70c10
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Re: Vintage Air in a Crewcab

Quote:
Originally Posted by LH Lead-Foot View Post
I don't know about the components use with Vintage Air, but there are several choices for everything. Aftermarket, OEM or the bone yard find. One thing you will have to deal with is R134a. It has a smaller molecule that R12 and requires excellent seals and barrier hoses. One item some may not know, is the evolution of GM's A/C condensers over the years. While in the 70's, the tubes on the condenser look like you could roll a ball bearing from one end to the other. This was ok for getting rid of latent heat using R12. R134a actually carries more BTU's of heat energy per pound than R12. It just boils at a slightly higher temperature. This why the amount of R134a is way less in systems that use it. Here is what GM engineering did...they went to extruded aluminum serpentine condensers with small holes. Now in 2000, they went a step further and extrusion process allowed for tiny perfect uniform holes in a row of tubing. This greatly increased the removal of latent heat, making R134a systems even more efficient. Think of two systems, like front and rear, but one condenser. The photos attached below will show why. I cut one apart to get a good shot. This creates an issue; flush or replace? If you experience a compressor failure, you will have to replace the new style. If your in a bone yard hunting, look thru the grill at the condenser rows. If they are thinner than a book of matches, you have the new style.
Great information Leadfoot, have you ever heard of anyone using a newer R134a condenser on an older R12 system with success? I don't see a problem with being more efficient...
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Old 02-20-2018, 12:02 PM   #7
RADustin
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Re: Vintage Air in a Crewcab

Quote:
Originally Posted by hatzie View Post
The volume in a crew cab isn't much bigger than a fullsize four door sedan cabin. It might be the same volume.
Is the evaporator noticeably smaller than the stock Harrison unit?

Plenty of room for a huge condenser. I read somewhere the stock CK truck condenser was around 1/3 larger than it really needed to be.
here lies the problem. Many are out there bad mouthing VA for use in crews, but really the performance of the AC system heavily relies on the installation quality and component selection. The condenser VA supplies is basically a stock replacement c10 unit. So it is rather large.

my Dad was a GM certified tech for many years back in the 80s I believe. He seems to remember the stock square body ac being rated around 5 tons. Not sure if anyone can confirm this?

The folks on facebook were claiming to not get vent temps below 50F. I find this hard to believe or installation/charging error. My brothers truck blows in the 30s.

Quote:
Originally Posted by LH Lead-Foot View Post
I don't know about the components use with Vintage Air, but there are several choices for everything.
this is really good info- thanks!
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Old 02-20-2018, 01:54 PM   #8
LH Lead-Foot
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Re: Vintage Air in a Crewcab

For ryanv70C10, to install the newer type condenser in any system would increase it's efficiency, after all you are removing heat from the cabin to the outside. Each adult produces about 600 BTU of heat energy, then add sun loads thru the glass, humidity, ambient air temp...all adds up. The in-line A/C system air delivery systems would be like the Vintage Air systems, making less resistance for the air movement across the evaporator to crate conditions to cause the refrigerant to boil. This type is more efficient. Don't forget to clean the evaporator if you have not had eyes on it for years. Same for cabin air filters. Without heat, air volume, no boiling or little in the evap. Just because a pressure drop occurs, does not mean the refrigerant is cooling as R12 boils @ -21.6F & R143a boils @ 14.9F. Without heat, it just remains liquid with little boiling. This why computer controlled systems deny A/C operation when it's too cold, low system pressure and WOT...to protect compressor guts, plus adds to acceleration.

The question by RADustin about tonnage is a little more difficult as 1 ton of A/C is derived by amount of BTU's to melt 2000 lbs. of ice per day. Thus, 143 BTU melts 1 lb. of ice per hour, 1 ton requires 286,000 BTU per 24 hours. This equals 11,917 BTU per hour or rounded up to 12k BTU. The HP required depends on the efficiency of that system, meaning the type of refrigerant, compressor's capacity at different speeds and the condenser type & air flow. The over all view is 2-3 HP will be required to operate a system of 20,000 BTU. So, almost 2 tons using 2-3 HP. At least the OEM Axial-6 GM compressor, that weighs in at 42 lbs. is the difference of an aluminum block versus a cast iron block engine. I guess sometimes, size does matter. Ha,Ha!
After a nasty donor bone type lumbar fusion in the late 80's, I was placed into the original Universal Technical Institute, in Omaha, for automotive instructor. But I was called upstairs to fill in for an HVAC instructor who was injured. A different world all together when your talking "Wet-Bulb" effects on gauge pressure, convert to BAR, super-heat and sub-cooling for proper charging of systems in HVACR. Paid 12k a year. Wow! I went to the Buick dealer after 11 months of sucky pay.
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Old 02-20-2018, 02:21 PM   #9
RADustin
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Re: Vintage Air in a Crewcab

Quote:
Originally Posted by LH Lead-Foot View Post
A different world all together when your talking "Wet-Bulb" effects on gauge pressure, convert to BAR, super-heat and sub-cooling for proper charging of systems in HVACR.
last year I had to understand the derivation and how to use a psychometric chart to take my PE exam in mechanical engineering. That was difficult..especially separating entergy units to remove heat from energy units to dehumidify.

once known though, the engineer is easy. The dimensions to engineer to are more difficult to attain. The OEMs spend millions to get design forces and values. It would be nice to know what the design specs were for the crew cabs.

Either way I personally feel it's more important to get a large condenser and a high CFM blower than large evaporator and ultra efficient ducting. No doubt the VA unit has a strong blower and the condenser in the squares is fairly large. I still just don't see how the VA unit doesn't work well.
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Old 02-20-2018, 03:15 PM   #10
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Re: Vintage Air in a Crewcab

I guess I have to admit I’m not up on all the numbers jargon of BTUs, tonnage and condensor airflow ratings. What I do know is how to restore/overhaul factory GM Frigidaire and Harrison AC systems while converting to R134A since about 1996 when I was big into building 70-72 Montes at the time. I tend to prefer Smokey Yunicks analogy when it comes to these kinds of debates:

“People spend too much damn time thinking about it and less time doing it”! lol

So after years of doing factory AC overhauls what I’ve found to be critical in older applications is:

-Excellently sealed ducting, firewall enclosure
-Insulated interior cabin-doors, floor and firewall
-Tinted glass
-Electric fans (and not the cheapo aftermarket crap-HD factory 4000+ CFM fan(s))
-Upgraded wiring size all throughout the critical parts-resistor board, switch and blower
-Install ONLY new compressor along with drier amd orifice tube


I wanted to add also-clean out that AC evaporator!! You’d be surprised how much crap gets wedged in there!
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Old 02-20-2018, 10:48 PM   #11
Greenlee
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Re: Vintage Air in a Crewcab

I’ve had VA in my truck (regular cab) for about 5 years. I installed it myself and it works great. I haven’t had any problems with it whatsoever. The AC is ice cold and the heat is hot.

I’m not quite as impressed with the defrost. I’m in Houston where it’s humid. It works, but it only works well with the fan on high. Overall, I’m very happy with the system. I would think it would work just fine in a crew cab.
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Old 02-21-2018, 01:22 AM   #12
hatzie
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Re: Vintage Air in a Crewcab

Quote:
Originally Posted by ryanv70c10 View Post
Great information Leadfoot, have you ever heard of anyone using a newer R134a condenser on an older R12 system with success? I don't see a problem with being more efficient...
Folks use parallel flow condensers. I did. It's not necessary. You can get nearly the same performance with a stock replacement style condenser. They're just massively oversize for the cab volume.

Something to keep in mind. The old open condenser can be flushed when you have a compressor failure that spews trash through the system.
More modern serpentine and even parallel flow condensers with smaller passages generally are just so much scrap when a compressor bites the dust.
The Harrison A6 compressors are massively oversize and eat more fuel than the newer R4 radial compressors but they will freeze you right out of the cab even on R134A.
You just have to make sure the hard parts of the system are clean clean clean, you actually vac it down for long enough to boil all the condensation out of the system, the Ester oil charge is the correct volume, and the soft parts like hoses, o-rings, new dryer, and gaskets are R134A compatible.
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1969 Dodge Polara 500 B383, A833
1972 Ford F250 FE390, NP435/NP205
1976 Chevy K20, 6.5L, NV4500/NP208
1986 M1008 CUCV
2000 GMC C2500, TD6.5L, NV4500
2005.5 VW Jetta BRM PD-TDI, 02J 5 Speed
2009 Impala SS LS4 V8


RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.
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