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I actually was just going to remove the AC altogether and save the weight but I’m getting old so I guess it stays. Looking for info and posts from anyone that has relocated their AC condenser to the front of the car and used the R-12 substitutes such as Hot Shot, Freeze 12, etc., and/or performed the R-134 conversion.

Specifically:
1. On the condenser move to the front, I’m not looking for any debate about which condenser location is better. I have a set of 180s exiting in the stock condenser location so the condenser move is a foregone conclusion. I already have a very nice condenser that will package up nicely up front.
2. Do the R-12 substitutes perform well and with standard AC hardware? Some claim full R-12 compatibility and others say they require evacuation and filter/desiccant change and/or evac.
3. I actually have a working R-12 system but will need to disassemble it in the move. Is anyone still collecting and reissuing R-12?
4. On the R-134 swap, it would certainly be an easy time for me to do it. I have the (new) condenser performance for it, and will already need to move and replace the desiccant and replumb everything (with hard lines where possible). I also have an Sanden rotary compressor, albeit R-12, but at least mounting bracketry and pulley work is done. After all that will already need to be done, it’s not much more work to change the swap compressors (or maybe just seals)and the expansion valve. For those that have made the move to R-134, were you happy with it?

I searched but the forum seemed a little thin on the topic most post were quite old so not much use for the R-12 bits.

Best,
K
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Pantera AC Article I wrote several years ago

When I first bought my Pantera the AC didn't work. The system was completely stock and still had the original York compressor. Since the hoses looked like they were in good shape, (and one of the local Pantera vendors told me I should stick with R12), I decided to just replace the pump with a new style rotary compressor and install a new receiver-dryer.

The new compressor had o-ring type hose connectors so the vendor supplied adapters so I could connect my original compression type hoses to the new compressor. These adapters were the start of my first major problem.

When I connected my original hoses to the new compressor I didn’t notice that one of the adapters had turned sideways. As I tighten the hose it did get tight but not as tight as I would have liked. It felt kind of funny like maybe it was going to strip so I stopped. At this point I should have taken it back off and checked it out but because it was fairly tight I let it go.

I found a local AC shop that sounded like they knew what they were doing so I headed there to have the AC charged. The guy at the front counter said they could do it and took the car around back where the shop doors were. You could not see the shop from the waiting room. I didn't feel comfortable that they knew what they were doing on the Pantera so I walked around back by their doors. When I got there 2 of their technicians were looking over the car with a confused look on their faces. I pointed out where the compressor was as they couldn't seem to find it. As I watched from the door, (outside of the shop) I was told by another employee that I could not watch and that I had to go back to the waiting room. My theory is if they are afraid I might see them do something wrong to my car then I can't trust them with my Pantera. After some words with the management I had the work stopped, (before it was really started) and went on to find another AC shop I could trust.

On my way home I found another AC shop that didn’t mind me watching so I decided to have them evacuate and recharge the system with R12. It charged up fine. They put some dye in as well to help detect any leaks that might be present. It was blowing real cold. Right before I was about to leave I did notice a couple of drips from the hose fitting that I was having trouble with before. The technician said I could simply tighten it up when I get home. I should have done it there incase of a problem but I didn’t.

After paying the $250 bill for labor and 3 pounds of R12 I was on my way home with the AC working great! 34 degree air the whole way home. Once home I jacked up the car to tighten the fitting (still not knowing the adapter had turned sideways).

A couple of turns with the wrench and a slight snap noise and my expensive R12 was leaking out badly. I called the AC shop back up and they said to get back down there as quickly as possible so they could recover as much of the R12 as possible. I raced back down there only to find out it had all leaked out!

Once we removed the hose from the compressor we found the adapter had turned sideways. The snap I felt was when it cracked/crushed when I tried to tighten the hose. Darn, I should have checked it when I knew it didn't feel right. Oh well, live and learn.

I asked the AC technician to put the correct type of ends on my hoses and recharge the AC. Another $250 later I was on my way home with my AC working great again!

The car sat for about 4 months after that since I had other projects I was doing to the car. When I got it on the road again I noticed the AC wasn't blowing cold any longer. I obviously had a leak. I could see it was not empty, but just low as I could see a stream of bubbles in the sight glass. I had a can of R12 from years ago and decided to top off the system after tightening up all the connections. This is when I found that one of the hose ends was leaking where the new crimped end was installed. Apparently they didn't get the hose pushed on all the way before they crimped it.

After fixing the hose end I now have to charge the system again. This is getting ridiculous and very expensive. I decided to try Freeze12 since it is touted to be almost as good as R12 but affordable. I have also heard that it has worked well for some. Did you know that Freeze12 is 80% R134a?

After charging the system with Freeze12 it did work but not nearly as good as the R12. It would get the vent temperature down to about 50 degrees on a 95 degree day but that was about it. I was actually ok with that since it was a lot better than no AC and I had already wasted so much money on R12.

I drove around with the AC on, on a VERY hot day. It was working ok when all of a sudden one of the hoses let loose.

I really considered just leaving it broken since I had wasted so much time and money and was still no better off than day one. My problem is I just can't leave something broken on my Pantera. If it is there it must work. This is when I decided a completely new R134a system is what I needed. No more messing around. EVERYTHING new! And with R134a I can service it myself.

After doing a lot of research on my options I decided to go with a condenser in front of the radiator. I am told a properly designed R134a system will work as good as the 30 year old R12 system the Pantera came with. The key is the condenser. With the new Parallel Cross Flow condensers of today R134a will work quite well in our cars. I could have put the condenser in the back but I wanted it up front in the cool air.

I bought most of my parts from Vintage Air. Their prices are very reasonable and have everything you will need except for the evaporator if you plan on changing that as well.


All the hoses were changed to the newer style barrier type hoses and are much smaller than the older bulkier hoses of 30 years ago.

Since I am going to change everything the old evaporator had to go as well. I sent my old AC/Heater box to Pantera’s by Wilkinson. Steve built me a new heater/evaporator core where he removed one row from the heater core and made me a new evaporator that was one row bigger.

One of the nice things about the new evaporator is it is also a parallel flow unit, much like the condenser. It is basically 4 2 row evaporators stacked together. So with the bigger and more efficient Condenser up front and the bigger evaporator under the dash this system should be blowing out ice cubes (with R134a)!

Parts List:

Vintage Air Parts:

Compressor, Sanden 508 134a 04808-VUA $199.00
5’ #8 Hard Line 12561-VCD $ 19.50
14 x 22 Super Flow Condenser 03262-VUC $149.00
Receiver-Dryer w/pressure cutout switch 07323-VUC $ 59.00

Pantera’s by Wilkinson

Evaporator $550.00
Expansion Valve $ 85.00

All new hoses made by local hose shop $200.00

I am happy to report that the new system works great! I have 36 degree air blowing out on a 95 degree day. I should have just done the right thing from the beginning.

The funny thing is the same vendor that said I should stick with R12 is now telling customers that they should go with R134a. I totally agree at this point. I can now service the system myself and at a reasonable cost.

I have heard of people getting the 509 certification so they can buy R12 and service the system themselves. This is ok but R12 is still going to be expensive. For me, after everything I have been through, R134a is the only answer. It’s the old pay me now or pay me later kind of thing…
Give Ebay a look for R12. Lots of it. Around $20 per 12 oz can.

Seller will ask you for a declaration that you will forward the product to an authorized installer. That's all.

Stock hoses, rotary compressor, new receiver dryer and properly evacuated. Held 29" vacuum for over 24 hours, so I charged her up.

I used 3 12 oz cans and a +/- 6 oz can with an oil charge about 4 years ago. Still blows cold.

Also added a binary switch to protect the system from problems with pressures outside the operating norms. I would use a trinary switch next time for condenser fan control too.
quote:
Originally posted by Panterror:
I actually was just going to remove the AC altogether and save the weight but I’m getting old so I guess it stays. Looking for info and posts from anyone that has relocated their AC condenser to the front of the car and used the R-12 substitutes such as Hot Shot, Freeze 12, etc., and/or performed the R-134 conversion.

Specifically:
    1. On the condenser move to the front, I’m not looking for any debate about which condenser location is better. I have a set of 180s exiting in the stock condenser location so the condenser move is a foregone conclusion. I already have a very nice condenser that will package up nicely up front.
    2. Do the R-12 substitutes perform well and with standard AC hardware? Some claim full R-12 compatibility and others say they require evacuation and filter/desiccant change and/or evac.
    3. I actually have a working R-12 system but will need to disassemble it in the move. Is anyone still collecting and reissuing R-12?
    4. On the R-134 swap, it would certainly be an easy time for me to do it. I have the (new) condenser performance for it, and will already need to move and replace the desiccant and replumb everything (with hard lines where possible). I also have an Sanden rotary compressor, albeit R-12, but at least mounting bracketry and pulley work is done. After all that will already need to be done, it’s not much more work to change the swap compressors (or maybe just seals)and the expansion valve. For those that have made the move to R-134, were you happy with it?

I searched but the forum seemed a little thin on the topic most post were quite old so not much use for the R-12 bits.

Best,
K


I just relocated my condenser to the front of my Pantera and used Redtek, which is a R12/R134 drop in replacement. It works just like R12 and only runs a bit higher on the low side then R12. I have also been using it in one of my pickup trucks for years and it seems to be just as good as R12.

I had used Redtek in the Pantera for a number of years and had good luck with it when the condenser was in the back. What I did find is that after the ambient temperature got above 100 degrees, the air conditioner did not perform very well. At this time I am waiting for some near 100 degree days to test the new system, which I am sure will work as expected.
A few details from when I moved our condenser to the front 10 yrs ago.
First, I used a condenser from a mid-80s Datsun pickup- same length & width but 1/3 the thickness. It fits with a laydown Fluidyne aluminum radiator and cause no water temp increase. The mini-pickup's cabin is close to the size of a Pantera cabin. I also converted to R-134A (which is now illegal in Europe, so dunno how long cheap U.S. availability will continue). When converting to R-134A, the filter screen should be removed from the evaporator valve under the dash for higher flow from the r-134a, which is not as good at refrigeration as R-12. Barrier hoses use o-ring fittings while OEM use 45 degree fittings, so that causes more adaption.

Finally, I use a shorter-but-larger-OD aluminum dryer can from a semi-truck, mounted up front in the angle where the right inner fender and firewall come together. The lid clears without chopping a hole for the can to drop into. That means the dryer window is easily visible when the front trunklid is opened. I also ran Aeroquip lines up to a small panel under the quick-removeable access door in the rear firewall, so freon hookups can be done with all 4 wheels on the ground. Note- Aeroquip says regular stainless-armored teflon lines will leak freon thru the tubing; this application takes special lines.
Thanks for replies thus far. I’m planning on keeping my car until I kick. Since the R-12 legislation was circa mid 1990s and it’s still around, seems like 134a should be around for a good while and though it’s tempting to stay with R-12, I'd probably regret not addressing it while the engine bay and cockpit are empty and all fluids drained.

I have to open the AC system to move the condenser. There’s just no way around it and I don’t have evac capability nor will my car be mobile to deal with the current R-12 charge. It’s ashamed because R-12 is (was) a great refrigerant. I doubt I will be able to get anyone come to me to pump/recover a couple pounds of R-12. If I convert to R-134 now it seems it would reasonably assure good serviceability well into the future.

I originally thought stainless hard lines (routed under car) with short barrier hose between components for strain relief may be the way to go but it probably means more joints/fittings which may be bigger leak culprits than the length of barrier hose I’d save. I spoke with a local distributor and I can buy bulk hose and fittings, cut to length, install fittings and they will crimp for me….common sense says it may be pretty hard to beat that. I just need to settle on the components and routing.

What’s the preferred hose routing from compressor to front condenser? Under car? Through interior tunnel? Through the rocker? Any Pro’s/Con’s? -Thanks for comment on drier position Jack….

I’ll still need to source the expansion valve desiccant/accumulator, Sanden 508 or similar for 134a, bi/tri-nary switch. Any favorite recommended sources other than Vintage Air and Be-Cool? Some of our PCar vendors? I must source and locate components before the lines can be done.

Other than expansion valve swap has everyone found the existing evaporator coil to be adequate in the 134a conversion? I note the remark above, but must say like all my projects, my engine swap has evolved into a full blown upgrade program and I’m not eager to add pulling the dash too....I've already succumbed to the "while I'm at it" syndrome...just cant seem to help myself.

Even though I tried diligently, there’s a bunch of things that did not swap straight across my engine as far as pulleys, accessories, and other seemingly minor but sort of nagging time consuming things. The 180 install will require some additional cosmetic work to rear of the car and some heat shielding and I suspect coolant tanks & line (again). I have new geometry front suspension to install, EPAS, the (new/other) ZF already has M1 CV flanges and I have CV companion flanges to install on the rear uprights. I’ll need to pull the uprights to properly torque the axle nuts. I have an electric vacuum pump and plenum system I’ve put together to install (I won’t have enough manifold vacuum). I also need to take a close look at my alternator and power budget. ……none are big deals by themselves but it all adds up….and I’m looking to turn the corner toward a higher rather than lower state of assembly soon.

Best,
K
Kelly,

You may as well pull your dash and replace the evaporator/heater core while you're at it. Wilkinson sells them with a thinner heater core and thicker evaporator, complete with O-ring (R-134a) fittings (which saves you from using adapters). If I'm not mistaken, the manufacturer sells direct on eBay. Just be sure it comes with the correct fittings if you go the eBay route.

Aeroquip braided SS A/C hose and fittings are reasonably easy to make-up yourself. Not cheap though!

Oh, and while your dash is out, you may as well install a new three-speed blower motor.

Having the dash out makes it MUCH easier to install the EPAS too!

OK, now that your dash is out and you're installing your EPAS, send your speedo to North Hollywood Clock & Speedo to be converted to electric operation. Rather than use a trans driven sending unit, install a GPS sending unit under the dash. Now you can install a dedicated, "much nicer than the one that came with your EPAS", sending unit on your ZF (for the EPAS). There's a gauge shop in Milwaukee that has an electric sending unit that eliminates the ZF's angle drive. I have the info somewhere. The Veglia sending unit from an Si is nice too. Some Alfas use the Si's Veglia sending unit but I'm not sure if the drive pin is the same.

Sorry, I guess I should stop now! You've heard the expression "misery loves company" :-(

David
quote:
Originally posted by David_Nunn:
Kelly,

You may as well pull your dash and replace the evaporator/heater core while you're at it. Wilkinson sells them with a thinner heater core and thicker evaporator, complete with O-ring (R-134a) fittings (which saves you from using adapters). If I'm not mistaken, the manufacturer sells direct on eBay. Just be sure it comes with the correct fittings if you go the eBay route.

Aeroquip braided SS A/C hose and fittings are reasonably easy to make-up yourself. Not cheap though!

Oh, and while your dash is out, you may as well install a new three-speed blower motor.

Having the dash out makes it MUCH easier to install the EPAS too!

OK, now that your dash is out and you're installing your EPAS, send your speedo to North Hollywood Clock & Speedo to be converted to electric operation. Rather than use a trans driven sending unit, install a GPS sending unit under the dash. Now you can install a dedicated, "much nicer than the one that came with your EPAS", sending unit on your ZF (for the EPAS). There's a gauge shop in Milwaukee that has an electric sending unit that eliminates the ZF's angle drive. I have the info somewhere. The Veglia sending unit from an Si is nice too. Some Alfas use the Si's Veglia sending unit but I'm not sure if the drive pin is the same.

Sorry, I guess I should stop now! You've heard the expression "misery loves company" :-(

David


Man…...that's good advice but just plain evil. You’re like the Hannibal Lecter of the PI Board. Being OCD yourself gives you an unfair advantage….but take care or I’ll expose to all that it’s just a ruse and you actually have a bone stock car….and then send a letter to your Dr. advising your meds and therapy are no longer effective.

Jester

Best,
K
quote:
One of the nice things about the new evaporator is it is also a parallel flow unit, much like the condenser. It is basically 4 2 row evaporators stacked together. So with the bigger and more efficient Condenser up front and the bigger evaporator under the dash this system should be blowing out ice cubes (with R134a)!

Hmmm.

I am aware of the upgraded evaporator Wilkinson sells, have one in 2511.

But what I bought, and what is offered on eBay, is NOT a parallel flow style.

It is a tube and fin style, same as OEM.

More freon tubes, less coolant tubes.

Can you provide a photo of the evaporator Steve installed?

Larry

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quote:
Scott,

How is the R-134a expansion valve you bought from Wilkinson different than one you would have bought from Vintage Air?

Why does it feel like I'm asking a dumb question???

David


It cost 3 times as much and I like supporting Pantera Vendors! lol...

At the time I didn't know much about AC and didn't know if there was something Pantera specific about it so since he was making me the Evaporator, I had him through in the expansion valve. In hindsight, I should have purchased from Vintage Air...
Inside the evaporator valve is a sliding plug and a spring; the spring may be different strength than in an OEM valve for R-12. And of course the tiny conical screen filter in the side-leg is usually removed from r-134a installations. That screen catches a lot of powdered debris from ancient dryer cannisters, so maybe with R 134a one should change dryers every so often? Or put the screen back in and see how it affects coolness?
quote:
Originally posted by ZR1 Pantera:
quote:
Scott,

How is the R-134a expansion valve you bought from Wilkinson different than one you would have bought from Vintage Air?

Why does it feel like I'm asking a dumb question???

David


It cost 3 times as much and I like supporting Pantera Vendors! lol...

At the time I didn't know much about AC and didn't know if there was something Pantera specific about it so since he was making me the Evaporator, I had him through in the expansion valve. In hindsight, I should have purchased from Vintage Air...


Scott, is this the Vintage Air Valve?

http://www.summitracing.com/parts/vta-33076-vui

Best,
K
the R-12 substitutes such as Hot Shot, Freeze 12, etc.

Kelly,

One big issue with using the substitutes is any shop still doing R-12 service will likely sniff your system prior to working on it. If they find the substitutes they will not work on your system. That is because the substitutes may clog their machine or contaminate their recovery tank.

Of course, if the system is accidentally vented to the atmosphere prior to a visit to the shop, there isn't that problem.

R-12 is easily found for $20-$30 a can on eBay or Craig's list. I recently bought a virgin, still with the plastic-sealed-valve 30# jug of R-12 for $375.

I have my own Robinair 17700-A recovery/recycling/recharging R-12 machine I bought from the local L-M dealer about 8-10 years ago for $100.

Larry
Larry
quote:
Originally posted by LF - TP 2511:
the R-12 substitutes such as Hot Shot, Freeze 12, etc.

Kelly,

One big issue with using the substitutes is any shop still doing R-12 service will likely sniff your system prior to working on it. If they find the substitutes they will not work on your system. That is because the substitutes may clog their machine or contaminate their recovery tank.

Of course, if the system is accidentally vented to the atmosphere prior to a visit to the shop, there isn't that problem.



The fine for "Accidentally venting" refrigerant to the atmosphere is $50,000.00 for a individual and $1,000,000.00 for a company or business for every instance.

If i found anyone deliberately dumping refrigerant i would report them immediately.

Would you think it was ok to smash up your kids school ? Then why smash up your kids world ?


There is no way available to the average A/C shop for them to tell what gas is in your system. They rely on assumptions based on the age of the system, the types of fittings used, what was known to be used in that type of car, labels on the system itself and word of mouth of the owner.

Any of those assumptions may be wrong, especially in a old car where its A/C history is unknown or vague.

Any one could have put anything in it at any stage.

Shops know this and they are fully able to cope with it.

Any BS they might tell you about unknown refrigerants clogging up their gear is just that, "BS".

It would be just used as an excuse to charge you twice as much (or more). If they tell you they cant handle unknown refrigerants then go some where else.

It is another attempt to keep Air Conditioning/Refrigeration in the realm of a "black art" only to be practiced by "voodoo witch doctors" and the average car owner must pay the high priests a large sum to get their old system worked on, updated, repaired because of all kinds of mythical problems beyond reasonable comprehension.

One of the many old time scams of the car A/C mechanic was to tell owners that the "gas breaks down and goes bad" after a while and you need a yearly recharge.

This is total shibe.

One of the major problems with Dichloro-Diflouro-Methane (R-12) was that it was one of the most stable chemicals ever created by man and thus persisted in the enviroment indefinately causing all kinds of problems. (Ozone depletion)

It didn't break down at all, so why did Mr car A/C mechanic tell you it did ? To play on your ignorance and screw you for more money needlessly.



If you want to play around with your A/C system and do repairs, mods, updates ect, buy a recovery unit.

It will make your life much more pleasant. You will be able to pump out your system, save the gas, work on it, fix leaks, vacuum pump it, recharge it and all at your own leisure, no rush trips to the A/C shop and you'll only need to do that a few of times and it will pay for it self. I've had to pump my system out and recharge it a few times in a day in the effort to seek out a elusive slow leak (the hardest to find) that would have cost me a bundle if i had to do it through a shop.

Shops won't fix slow leaks (leaks that take 2,3 or more months) because they are notoriously hard to find, they often don't leak oil with the gas so there is no tell tail trace to follow.

Hoses often leak refrigerant through the walls of the hose (very very slowly) so there is no trace, but when you go to use your A/C after a 4 or 5 month break it's not cold, the refrigerant has leaked away.

I like to use stainless steel tube for refrigerant lines rather than hoses, especially the compressor discharge line (it gets very hot, bad for any kind of rubber) and the liquid lines. If extra flexibility is needed coil the stainless tube up like a spring, it will act just like that, absorbing any vibration, movement or twisting.

Another source of slow leakage was the sump and head gaskets on the old York compressors. The gaskets cold be sealing perfectly, no oil leaks, but the refrigerant would escape. How ? It would leak through the gasket material itself, not around it but through it !

My advise for compressors is replace the York with the Sanden SD7H15. This is around the same capacity as the York but is a much better compressor capable of much higher speeds. SD508 compressors are a bit small (8 cubic inches).

York's are 9.5 or 10.5 cubic inches. SD7H15 are about 10 cubic inches. Drive the SD7H15 faster than the York was driven.

There is no such thing as a R-12 or R-135a compressor. They are mechanically exactly the same. The only differences may be different types of oil may be inside them and different compound o-rings and seals may be used. But i have used R-12 compressors with R-134a with no problems. Compressors don't care what gas is going through them, i've used a Sanden SD508 as a air compressor !

Does R-134a work in a old R-12 system ? Yes, but it is not as efficient in that system.

How do i modify my old R-12 system to get the best efficiency from R-134a ?

To cut the BS you need more condenser capacity to be able to dump more heat and produce more liquid (refrigerant), you need more liquid storage capacity (larger filter dryer) and more evaporator capacity (larger evaporator) to enable a larger volume of liquid to boil off thus cooling your cars interior. That's why the SD7H15 must run faster than the York,it needs to physically move more R-134a than the York had to move R-12.

You will also need a new thermal expansion valve (TXV) to suit R-134a.



A note on receiver/dryers. Anytime you work on a system they need to be replaced !!!

The most important thing about them is the desiccant they contain. It is there to trap water (vapor/humidity) that gets into the system when it is open to atmosphere (eg: when you are fixing a leak or replacing a component). Water will kill your A/c stone dead !
It doesn't take all that much moisture to overwhelm the desiccant and once that happens water and refrigerant and refrigerant oil are a very bad mix.
quote:
There is no way available to the average A/C shop for them to tell what gas is in your system.

If I can manage to have one of these on my garage shelf, I imagine an average A/C shop could have one.

A standard R/R/R unit has only one recovery tank. No shop will knowingly contaminate that tank with any of the R-12 substitutes on the market.

Yes, the substitutes 'work'. But innocently mention you've added them to your system, and the shop will likely decline to work on it.

Larry

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quote:
If you want to play around with your A/C system and do repairs, mods, updates ect, buy a recovery unit.

It will make your life much more pleasant. You will be able to pump out your system, save the gas, work on it, fix leaks, vacuum pump it, recharge it and all at your own leisure, no rush trips to the A/C shop and you'll only need to do that a few of times and it will pay for it self. I've had to pump my system out and recharge it a few times in a day in the effort to seek out a elusive slow leak (the hardest to find) that would have cost me a bundle if i had to do it through a shop.


The R-12 R/R/R units are now dead weight at most shops. They are regularly seen on eBay and Craig's list.

Shipping expense is a deal killer, but find one locally and negotiate the price down to your comfort zone.

As Aus Ford wrote, they can easily pay for themselves when you have a slow leak or are re-doing your A/C system.

Larry

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quote:
Originally posted by LF - TP 2511:
quote:
There is no way available to the average A/C shop for them to tell what gas is in your system.

If I can manage to have one of these on my garage shelf, I imagine an average A/C shop could have one.

A standard R/R/R unit has only one recovery tank. No shop will knowingly contaminate that tank with any of the R-12 substitutes on the market.

Yes, the substitutes 'work'. But innocently mention you've added them to your system, and the shop will likely decline to work on it.

Larry


I simply would not tell them.

I'd say i don't know what's in the system. Leave it to them to work it out and deal with it appropriately.

They have the means to deal with contaminated R-12, 99% of all systems that came in would be contaminated with something and so would not contain pure R-12.

Contamination is a well known problem and recyclers collect and purify used refrigerants for reuse.

Anyone that refuses to is acting purely for their own self interest and not because of some technical impossibility.

Anyone that expects to recover pure R-12 or any other pure refrigerant from a automotive A/C system is kidding themselves. By design Auto A/C systems are prone to contamination. I would expect to recover contaminated gas from all Auto A/C systems, not expect to recover pure refrigerant. They are kidding themselves.

I most certainly not encourage anyone to deliberately dump refrigerant of any type to atmosphere.
Aus Ford,

Thanks for the great information. I was particularly interested in your suggestion to use the larger Sanden SD7H15 compressor.

It seems that sometimes we Pantera owners use a particular item because it's just what everyone else uses. No one stops to ask "why" and/or "is there something better"? Perhaps the SD508 is such an item.
quote:
use the larger Sanden SD7H15 compressor.

I installed this unit last year, on the recommendation of John Buckman. Same physical mounting as the older Sanden that has been used for years by Pantera vendors.

If you are replacing the York, you'll need the same adapter plate used and sold by the vendors, and numerous eBay sellers.

It comes with o-ring fittings, but if you still have the stock flare fittings under your dash, all you need is the little "acorn" adapters to convert to serviceable flare fittings.

If you use R-134a then the factory supplied oil is fine. If you are still using R-12, you'll need to drain the factory oil and refill with R-12 compatible oil.

This outfit has sold several units to Pantera owners. They will toss in the adapters if you ask, and their pricing is likely as good as you will find.

Larry

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This is not in a Pantera but it is on a Cleveland engine. I'm assuming Pantera's mount the York compressor in the same position.

This is a photo of a SD7H15 (on the right) mounted in the same position as the York was using a adapter on the old York bracket.

The SD7H15 automatically runs faster than the York since the SD7H15 pulley is smaller than the York pulley. So no mods are required to achieve the slightly faster compressor RPM that is desirable.

On the left is a SD508 that is used as a air compressor in this installation (for pumping up tyres) Note the size of the two compressors is the same depite the SD7H15 having 20% more capacity (2 extra cylinders).


The owner of Vintage Air wrote a book on AC systems. I read part of it when I was engineering my sysytem. In it he discusses the how to pick the proper size displacement for your AC pump. He specific points out that the Sanden 7 series is to large for most auto applications. Unfortunately, I do not recall his reasoning. However, his publication is available or a call to Vintage Air would probably suffice. The 5 series was a better solution.

I'm simply addressing the point that someone was making about failure of others to think outside the box and following blindly the decision of others like lemmings. Actually, some past decision were based on research whether accurate or not. Bigger not always better.
JT,

Here's a paragraph that's taken from the Vintage Air catalog:

"Compressor Capacity Is Critical
Capacity is critical in selecting a compressor.
Why? The weak link in most aftermarket
air conditioning systems is the condenser's
ability to handle the demands of the other air
conditioning system components. These
demands are to condense the refrigerant
enough to keep the compressor head pressure
and corresponding refrigerant temperature
within acceptable operating limits (approx.
twice the ambient temperature of the day, plus
fifteen percent) and to supply the evaporator
with adequate refrigerant. Generally speaking,
if a compressor has too much capacity the
result will be excessive high-side pressure and
temperature, compressor damage and excessive
load on the engine. If a compressor has
too little capacity the system will suffer inadequate
evaporator performance. Our basic minimum
given in the condenser part of this article
is larger than most aftermarket systems
are using; however, we will use that as our
standard size condenser. A compressor of 8
or 8.5 cubic inches of displacement per revolution
is ideal for a classic car or truck with
our standard size condenser, and an average
size aftermarket evaporator (approx. 200
cubic inches of coil mass). We would always
lean toward a smaller compressor before
going to a larger one."
quote:
Originally posted by David_Nunn:

A compressor of 8
or 8.5 cubic inches of displacement per revolution
is ideal for a classic car or truck with
our standard size condenser , and an average
size aftermarket evaporator (approx. 200
cubic inches of coil mass).

We would always
lean toward a smaller compressor before
going to a larger one."



If you are replacing a 10.5 cubic inch compressor (York) in a old system you should replace it with another compressor of the same or very similar capacity, not one that is 20% smaller (SD508).

You would have to run the SD508 a lot faster than the York to make up the capacity shortfall and that just unnecessarily introduces more heat to the system from heat of compression and internal compressor friction that must the be dumped by the condenser in addition to the condensers normal load.

If also you intend to change refrigerants from R-12 to R-134a you the place a further requirement on the compressor as you will need to move a greater amount of R-134a through the system than you did R-12 because the properties of the two refrigerants are slightly different.

R-134a boils at a slightly higher temperature than R-12 (so it doesn't get as "cold") for any given evaporator pressure and also R-134a does not transfer the heat as well as R-12, so to move the same amount of heat as a given amount of R-12 more R-134a needs to be moved.

Think of A/C as a conveyor belt for heat.

You put heat on the conveyor in the cabin of your car, the conveyor takes it outside, then the heat is dumped to the passing air. The conveyor belt continues back to the cabin with the heat removed where you can put more heat on it to be moved outside.

If you have a big wide conveyor belt you can fit more heat on it, thus move more heat in any given amount of time, if it is small and narrow only a small amount of heat can fit on it, so you only move a small amount of heat in any given time.

Refrigeration is all about system capacity.

R-12 boils at -29.8 degrees C and R-134a boils at -26.1 degrees C (at 14.7psi absolute pressure), so it looks as if doesn't get as "cold". That's true it doesn't but -26.1 would be "cold" in anyones language so why doesn't it feel as cold in your car ?

Think of it this way, if we could get your car's interior down to 0 degrees C (32F) most people would say "gee wiz it's jolly cold".
A ice cube from your freezer is at 0 degrees C, but putting one ice cube in your car would have no effect on the temperature in your car you could possibly feel. But what about 1000 ice cubes ? Or 2000 ? Or 5000 ?

At some point if you continued to place ice cubes inside your car the interior temperature would fall to 0 degrees C.

This is capacity.

No ice cube is colder than 0 C, one ice cube does nothing to make you feel cool, but 5000 will. The temperature of the refrigerant hasn't changed but the amount of refrigeration has.

I have heard people say they are disappointed with a dashboard vent temperature of 15 degrees C and they want it "colder" say 2 degrees C. The reality is they don't really need it "colder", if all the air in the car could be maintained at 15 C they would feel cold.

Imagine if the A/C in your house or office was set to 15 C you would have to wear a coat or jumper.

What the car A/C needs is capacity.



As the article extract in the previous post said "Compressor Capacity Is Critical", it must be a match for other components in the system. Not too big , not too small. So if your current system has 10.5 cubic inches of compressor capacity replace it with as close to 10.5 cubic inches as you can. Not 20% smaller.

In the article extract they talking about new systems they are building up from scratch.

They have the luxury to choose the refrigerant from the word go, not try to get a refrigerant to work in a system designed for a refrigerant with different properties.

They can also choose condenser and evaporator designs and capacities at will, not be stuck with using what is already in the car or what could be reasonably expected to fit and in those circumstances with the components they use the SD508 may very well be suitable.

They may also have a stockpile of SD508's they want to get rid of.........Don't be fooled, financial incentives are more powerful than engineering ones when it concerns this "black art" of refrigeration. Many many customers have been made to purchase things they don't need or things not up to the task by car A/C mechanics preying on the average customers ignorance.



The Sanden compressors of any capacity run much nicer than the clanky old York. As i have said the small sacrifice of 0.5 cubic inches when replacing a York with a SD7H15 is worth it to get the SD7H15's smoothness.



.
quote:
Originally posted by LF - TP 2511:
Thanks, Scott.

As expected, what you received from Steve is a tube and fin style. That is the same unit I used.

A LOT of folks, sadly vendors included, somehow have gotten the wrong idea of what constitutes a "parallel flow" style.

Larry


Thanks for the replies and valuable discussion. –Very helpful.



The evaporator above looks like re-worked OE unit that borrows the position of one of the heater core coil stacks and uses it to increase the overall AC evaporator coil mass.

Does anyone know the evaporator coil mass of this or the stock OE unit? Alternatively, even just the overall L x W x H dimensions of the entire core would suffice in making a decent estimate for either unit. If anyone has that information a reply post would also be greatly appreciated.

The unit above and the OE unit appear to be slightly different in the configuration of the evaporator expansion circuit and this eBay unit below appears to be the same expansion circuit approach as the OE unit, except with the additional coil mass has been devoted to the evaporator similar the modified unit pictured above. It’s a big price for an evaporator/heater core.

http://www.ebay.com/itm/DeToma...em3ccbe71928&vxp=mtr

The following is just my take on the matter but with proper selection of the rest of the system components, I think sufficient performance can be achieved (at least that of the OE system) from R-134a, sticking with the OE evaporator, and utilizing a higher performing condenser in the much cooler greater airstream at the front of the car. I think the biggest challenge to the performance of the OE Pantera AC system design was the condenser sizing, location, and generally poor condenser fan performance. A better condenser and fan in the OE location would likely significantly improve the OE configuration performance for any refrigerant, but for a given coil mass you’ll never have the potential condenser performance that can be achieved in the front of the car, at least at speed, and probably under all conditions.

In my experience the overall OE Pantera system performance was adequate when it was at full charge (R12) and operating properly. So, I think the OE evaporator coil is probably sufficient if the rest of the system is at least equal the performance of the OE system, which I think can be easily improved. With properly selected components and control scheme I don’t think R12 or R134a is material.

A couple other observations on the compressor sizing discussion earlier in the thread; all of the displacements referenced for the York, and Sandens are the swept volume or displacement per revolution. You can’t properly size the compressor without also considering the compressor operating speed.

The pulley diameter on my old York style recip compressor is about 6” while that on my Sanden 508 is 5”. The York pulley size was evidently selected for the 5 1/2” Pantera (but also std sbf size) crank pulley. So the original compressor was underdriven and concluding that 10.5 cubic inch compressor is required neglects the intended drive speed. Since changing the crank pulley diameter would change the drive speed and performance of everything else it’s driving, common practice is to size the driven pulleys for intended operating speed of the accessories.

It so happens that though an 8.5 cubic inch swept displacement Sanden 508 compressor is 20% less than the York’s, but with the Sanden OE pulley, it will operate at ~20% higher speed than the York and thus have comparable pumping displacement, assuming similar volumetric efficiency, for any given engine speed. I don’t think that’s a coincidence? So yes, you do need to run the Sanden faster but I would contend Sanden’s wobble plate piston compressors are designed to run faster and 20% faster than a York unit is certainly no stretch for them. As near as I can tell, virtually all Sanden wobble plate passenger car compressors come with this a 5” pulley. According to the Sanden manual, all Sanden wobble plate compressors are rated for continuous operation at 4000 RPM and many 6000 RPM. This is compressor speed not engine speed. With a 5.5” sbf crank pulley, a (Sanden) compressor with a 5” pulley will run ~10% slower than engine speed. I will never approach that continuous compressor operating speed and only see excursions to 7krpm or so and when doing so will not likely bring the AC along for that portion of the ride. I have a high speed cut out but usually just turn off the AC for spirited driving.

With a displacement of 155cc/9.5 in3, the Sanden SD7H15 is largest displacement passenger car compressor Sanden offers. Now I certainly note and agree with more cylinders means smoother pulses/operation, and slower operating speed means longer life, but in my view unless you were going to increase the drive pulley diameter to enjoy those benefits, I just can’t imagine why it would be needed in a Pantera. I’d contend the Pantera has more modest overall AC capacity needs than most passenger cars for the following reasons. First, being a two-seater, the passenger compartment in a Pantera is small compared to full size passenger car. It has much less volume and less window area which means less solar load, and at most two people to keep happy. It does have close passenger proximity to the engine compartment firewall, but front engine cars not only have an entire firewall they also typically have the additional heat load from undercar exhaust, transmission, and engine heat passing under the car. In a Pantera, if you insulate the firewall (I have done so) you’ve probably taken care of the majority of the addressable heat load. Next the floor (I just have the factory Jute) and then the doors (I have nothing). Though you could undoubtedly get improvement (both thermally and acoustically) with attention to the latter two, I think very satisfactory results can be achieved without further insulation beyond the firewall.

There are downsides to installing a larger pumping capacity compressor than needed. More capacity means more power to drive it and this can lug engine speed down at idle and cause erratic idle problems. In addition to understanding how the pulley and drive belt scheme affects compressor drive speed, when comparing AC systems and components from one vehicle to another, what will be engine idle and cruise speed. It’s not a trivial matter because the compressor speed is proportional to engine speed, and in almost all cases the biggest challenge to the cooling capacity of any AC system is with the engine at idle and car at rest….it’s the lowest engine speed (refrigerant compression/expansion/flow), lowest air flow across the condenser, and the highest effective ambient temperature due to parasitic short circuiting of cooling air with engine compartment and pavement heat.

In my case, I will pay some price in overall engine cooling capacity for having the condenser in front of the radiator but I have a Ron Davis radiator and it’s just a great piece work. The guy makes a great radiator. Even at twice the OE HP I think I’ll be just fine for my use. If I was running the Silver State and at max power for prolonged periods I may take pause installing the condenser in front of the radiator……but, I’m not. It’s just a street car or it wouldn’t even have AC. -I’ll let you all know how it turns out.
On the subject of relative refrigerant performance and efficiency, here is succinct summary by a notable manufacturer and I’ve found it to be consistent with all the other technical sources. Pay particular attention to sections 1a-d, but especially 1d.

http://www.tecumseh.com/~/medi...ization-of-R134a.pdf

Another useful document for technical information regarding Sanden Compressors:

http://www.sanden.com/objects/...Service%20Manual.pdf

BTW Aus Ford, I really like your use of that SD508 as an onboard air compressor……very clever…..good on ya.

Best,
K
quote:
Originally posted by Panterror:

BTW Aus Ford, I really like your use of that SD508 as an onboard air compressor……very clever…..good on ya.

Best,
K


I used to live in a rural area many miles from a gas station and transport so to have the ability to pump up the tyres any where was a real Godsend.

It's simple to do and works really well.

You just need to set up a simple dry sump lubrication system for it as A/C compressors are lubricated by oil travelling through the system with the refrigerant.

Obviously that doesn't happen with air and you can't fill the sump with oil as SD508 doesn't have one and any level of oil in the compressor would back up against the bottom cylinders go past the single compression ring (no oil scraper) and be pumped out with the compressed air.

We could start a whole thread on this. PM me if you re interested in more detail.
quote:
Originally posted by Bosswrench:
Inside the evaporator valve is a sliding plug and a spring; the spring may be different strength than in an OEM valve for R-12. And of course the tiny conical screen filter in the side-leg is usually removed from r-134a installations. That screen catches a lot of powdered debris from ancient dryer cannisters, so maybe with R 134a one should change dryers every so often? Or put the screen back in and see how it affects coolness?


Does anybody have any photos of the tiny conical screen filter and its location?
Lots of good info .I am looking to move AC condenser to front of car too. the question I have. Is it better to run pipe under car or try to run threw door pan ? Just thinking it may get very hot with radiator pipes and back top heat on it .Has any one tried to run pipe that way. I know under car would be a lot quicker. I returned the condenser 14 x 18 I purchased from summit /vintage air . I ordered the 12 x 20 the 14 x 18 inch will only fit in my car if i move radiator bottom back . think the 12 x 20 will fit better . I was also told to have at lest 1 inch gap from condenser and radiator for better cooling.
quote:
Originally posted by pantera74Bills6976:
Lots of good info .I am looking to move AC condenser to front of car too. the question I have. Is it better to run pipe under car or try to run threw door pan ? Just thinking it may get very hot with radiator pipes and back top heat on it .Has any one tried to run pipe that way. I know under car would be a lot quicker. I returned the condenser 14 x 18 I purchased from summit /vintage air . I ordered the 12 x 20 the 14 x 18 inch will only fit in my car if i move radiator bottom back . think the 12 x 20 will fit better . I was also told to have at lest 1 inch gap from condenser and radiator for better cooling.


Under the car is simple to do with a hardline...

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