Let's talk about Dash air- 76 Birch - it's hot where i live

[dave silva]

I have not tested the coach AC. It had leaked down in 7 years but it did hold vacuum pretty well so I'm optimistic

But i have heard the dash air is not great to begin with. The coach came with all the usual upgrades but this is the one thing i would spend some
additional time and money on. Even in winter my car AC gets used at least one day a month.

So, can the stock AC adequately cool the whole coach when cruising? Or, can it cool the front half with a curtain across the back?

it was converted to R134 for but i would recharge it with Duracool (it has Jim Bounds fire suppression installed)

Are there any common A upgrades out there?
--
Dave & Ellen Silva
Hertford, NC

74 Birchaven, 1-ton and other stuff

 

[Ken H.]

Dave,

My '76 X-Birchaven's cockpit, isolated with a clear shower curtain behind
the seats (using the OEM track), was cooled quite well by the OEM a/c, even
here in GA. That was after incorporating the recirculating air mod,
cleaning the evaporator, replacing the seals on the hot/cold air door, and
converting to Duracool. It worked well enough that SHE usually had a
blanket over her knees.

Those mods are covered here:
http://gmcws.org/Tech/air_conditioning/air_conditing.html
and
http://www.gmcmhphotos.com/photos/g4637-type-ii-dash-air-condition-modification.html

This was helpful with some of the troubleshooting of the OEM a/c:
http://www.gmcmhphotos.com/photos/g4858-color-hvac-troubleshooting-charts.html

Eventually, however, I went a little further:
http://www.gmcmhphotos.com/photos/g5280-dash-air-conditioning-redesign.html

Ken H.

On Mon, Dec 28, 2020 at 7:58 AM dave silva via Gmclist <

> I have not tested the coach AC. It had leaked down in 7 years but it did
> hold vacuum pretty well so I'm optimistic
>
> But i have heard the dash air is not great to begin with. The coach came
> with all the usual upgrades but this is the one thing i would spend some
> additional time and money on. Even in winter my car AC gets used at least
> one day a month.
>
> So, can the stock AC adequately cool the whole coach when cruising? Or,
> can it cool the front half with a curtain across the back?
>
> it was converted to R134 for but i would recharge it with Duracool (it has
> Jim Bounds fire suppression installed)
>
> Are there any common A upgrades out there?
> --
> Dave & Ellen Silva
> Hertford, NC
>
> 74 Birchaven, 1-ton and other stuff
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[bd5av8r]

>
> You can always fire up the generator and run the roof AC in the event you
> need to cool the coach if the dash ac isn’t working.

Either Jim can help with the dash AC too

Sammy

> --

*Major Sammy "Ghost" Williams, CAP*

Coastal Charleston Composite Squadron

U.S. Air Force Auxiliary
gocivilairpatrol.com

 

[LQQKatJon]

Dave,

my experience with my dash air in 26' 1975 model, is it just never blew any volume of air that actually did any cooling to inside temps. I always
had it working, but I normally left it off, because temps would climb, and I would always end up running roof air, or opening up windows.

my friend has a 77, his will blow a larger volume of cool air. I don't think it would cool his 26' eleganza, but just driving in the front cockpit
area, it was tolerable. I would bet with a curtain it would be plenty cool.

your 76 birch, I guess I am not positive if it blows like the 77 or not like my 75.

the r-134, duracool, really does not make much difference, the issue is all in air flow vs heat gain.

I have been struggling with keeping my coach cool for years... I am finally optimistic that this summer is the summer. I am a believer in a good
generator and dash air. if one does not work, you have the other. or if you have my luck, you still cook in the coach.


--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/

 

[LQQKatJon]

Are there any common A upgrades out there? [/quote]


Vintage air is most common dash A/C upgrade. That tied with a newer Sanden compressor. get the biggest evaporator you can...


the old compressor is plenty up to the task, but some have experienced issues with rebuild units.

The newer sanden compressor has benefits of it's mounting bracket is simpler and allows for access to the valve cover on passenger side. It is
also very low load- 455 does not really know it is spinning it. the original compressor there is noticeable load on the engine.


I am running a sanden compressor now, have disconnected the OEM dash evaporator and am using a china copy under dash evaporator. The evaporator is
loud, and in the way, but it blows lots of cold air, but not enough for a hot day. I made the mistake of buying a 13,000 BTU evaporator. it was
cheap, but that is not enough BTU's. I will be replacing it with a different evaporator that is more like 26,000 btu. There are some 18000 Btu as
well. the normal one people install is the vintage air slim-line. I am not sure what BTU rating that one has.


--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/

 

[dave silva]

> the r-134, duracool, really does not make much difference, the issue is all in air flow vs heat gain.

Is there consensus on that? My understanding is that R134 does not cool as well as R12 and Duracool behaves a lot more like R12. Old vehicles with
the smaller components do not work as well after conversion to R134.

I have a 91 F150 - when i got the AC worked perfectly, but not as cold as i liked. It had been converted to R134. I dumped it and replaced with
Duracool and now it's freezing.

--
Dave & Ellen Silva
Hertford, NC

76 Birchaven, 1-ton and other stuff

Currently planning the Great american Road Trip Summer 2021

It's gonna take a lot of Adderall to get this thing right.

 

[adolph santorine]

I prefer Duracool on any vehicle that was originally designed for R-12

It’s easier on the compressors as well.

Take the heat/AC box apart, and CLEAN IT.

I use an aerosol coil cleaning product from the local HVAC shop, and a coil comb.

You’ll be amazed and disgusted by home much gunk you get out of the evaporator coil the first time you clean it.

Stay cool!

Dolph

DE AD0LF

Wheeling, West Virginia

1977 26’ ex-PalmBeach
Howell EFI & EBL, Reaction Arms, Manny Transmission

“The Aluminum and Fiberglass Mistress”

|[ ]~~~[][ ][] \
"--OO--[]---O-"

>

>> the r-134, duracool, really does not make much difference, the issue is all in air flow vs heat gain.
>
>
> Is there consensus on that? My understanding is that R134 does not cool as well as R12 and Duracool behaves a lot more like R12. Old vehicles with
> the smaller components do not work as well after conversion to R134.
>
> I have a 91 F150 - when i got the AC worked perfectly, but not as cold as i liked. It had been converted to R134. I dumped it and replaced with
> Duracool and now it's freezing.
>
>
>
> --
> Dave & Ellen Silva
> Hertford, NC
>
> 76 Birchaven, 1-ton and other stuff
>
> Currently planning the Great american Road Trip Summer 2021
>
> It's gonna take a lot of Adderall to get this thing right.
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[Jim Hupy]

One thing that often comes up in A/C conversations is air volume.
Frequently people equate fan speed/air volume with cooling effect. If "a
person" is overheated then they want to move air as forcefully as possible
(high fan speed) over their face and arms and other parts to cool down
quickly.
But, air moving at high fan speeds frequently does not exchange btu's
quickly enough (it doesn't cool down before it loses contact with the heat
exchanger) and travels through ductwork to blow forcefully out the vents
and over skin.
In a bunch of cases, a medium fan speed will produce colder air when
it reaches skin.
But human nature is what it is, and impatience rears it's ugly head.
"I am too hot, and I want cooled off right now!!!) becomes the quote of the
day.
No mechanical device can ever remedy that, no matter how efficient it
is. Just saying.
Jim Hupy
Salem, Oregon

On Mon, Dec 28, 2020, 8:32 AM dave silva via Gmclist <

> > the r-134, duracool, really does not make much difference, the issue
> is all in air flow vs heat gain.
>
>
> Is there consensus on that? My understanding is that R134 does not cool
> as well as R12 and Duracool behaves a lot more like R12. Old vehicles with
> the smaller components do not work as well after conversion to R134.
>
> I have a 91 F150 - when i got the AC worked perfectly, but not as cold as
> i liked. It had been converted to R134. I dumped it and replaced with
> Duracool and now it's freezing.
>
>
>
> --
> Dave & Ellen Silva
> Hertford, NC
>
> 76 Birchaven, 1-ton and other stuff
>
> Currently planning the Great american Road Trip Summer 2021
>
> It's gonna take a lot of Adderall to get this thing right.
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[mark sawyer]

IMO, R134a conversions are a complete waste of time. The people you hear who say they work, are generally in northern states where it just does not
get hot enough to notice the drop in performance. In a southern state with higher temps, I would look into one of the HC substitutes such as
Duracool, or, if you are concerned with the idea of running an HC in your AC system, R12 is available on Ebay or even Craigslist in many cases. It
generally runs between 20 and 30 bucks a can. So around 100 bucks or so for a full charge.... Expensive for sure, but not crazy expensive when you
consider a healthy system can maintain an adequate charge for years....
--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX

 

[Ken H.]

Neither I nor anyone else has mentioned an essential "clean it" location:
The firewall side of the evaporator. On the driver's side of the
under-hood HVAC box, there's a small gray plastic device with a 5(?) wire
connector plugged onto it. That's the resistor pack used by the dash
blower switch to set the fan speed. Two hex head sheet metal screws hold
it in place. Removing that provides (very) limited access to the air duct
formed by the evaporator and the firewall enroute to the large opening
through the firewall. A small diameter "nozzle" on a good vacuum cleaner
can be inserted into the resistor pack hole to clean out that duct -- I
found it full of all sorts of debris, including residue from a bird's
nest. You can't clean the evaporator well, but you may gain the incentive
to undertake the much more difficult task of removing the evaporator and
cleaning it properly.

By the way, if, like many of us, you don't like the a/c blower running ALL
the time, while you've got the resistor pack unplugged, disconnect the
Yellow wire (one way is to bend the pin it plugs onto over so it's not
connected). That will eliminate the OFF blower without affecting the other
blower settings. That yellow wire can also be used to supply voltage for
AUX-powered add-ons.

Ken H.

On Mon, Dec 28, 2020 at 11:51 AM Dolph Santorine via Gmclist <

> I prefer Duracool on any vehicle that was originally designed for R-12
>
> It’s easier on the compressors as well.
>
> Take the heat/AC box apart, and CLEAN IT.
>
> I use an aerosol coil cleaning product from the local HVAC shop, and a
> coil comb.
>
> You’ll be amazed and disgusted by home much gunk you get out of the
> evaporator coil the first time you clean it.
>
> Stay cool!
>
> Dolph
>
> DE AD0LF
>
> Wheeling, West Virginia
>
> 1977 26’ ex-PalmBeach
> Howell EFI & EBL, Reaction Arms, Manny Transmission
>
> “The Aluminum and Fiberglass Mistress”
>
> |[ ]~~~[][ ][] \
> "--OO--[]---O-"
>
> > On Dec 28, 2020, at 11:32 AM, dave silva via Gmclist <

> >

> >> the r-134, duracool, really does not make much difference, the issue
> is all in air flow vs heat gain.
> >
> >
> > Is there consensus on that? My understanding is that R134 does not
> cool as well as R12 and Duracool behaves a lot more like R12. Old vehicles
> with
> > the smaller components do not work as well after conversion to R134.
> >
> > I have a 91 F150 - when i got the AC worked perfectly, but not as cold
> as i liked. It had been converted to R134. I dumped it and replaced with
> > Duracool and now it's freezing.
> >
> >
> >
> > --
> > Dave & Ellen Silva
> > Hertford, NC
> >
> > 76 Birchaven, 1-ton and other stuff
> >
> > Currently planning the Great american Road Trip Summer 2021
> >
> > It's gonna take a lot of Adderall to get this thing right.
> >
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[LQQKatJon]

My thoughts and experience, is r-12 is nice but expensive.

Duracool is best and is what I run and use.

But.... if r134 conversion is done. They usually cool fine. And not worth trouble to pop open a working 134 system to change to duracool. It is
all about who charged it.

Theoretically r134 will not cool as well as duracool with the design of our condensors. But i have and know many people running r134 with systems
that blow cold.

If i tore apart a system i would go to duracool. But again duracool is a diy. If you ever plan on paying someone to work on your ac. Stick with
134. Shops do not like duracool at all.
--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/