A question for Greg Surfas...

[Edward Kenny]

Greg,

You mentioned in my last posting that I should be sure that the compressor in my '62 has fresh oil in it. I intend to do just that, but I need to know as to how I go about changing the oil in the compressor. I assume that I will be taking the compressor off of the car and emptying the sump by removing the screw on the bottom of said sump, correct? What kind of oil do I need and how much oil will it take? I intend to charge the system with either freon or R414b (per your suggestion).

Thanks in advance for the due diligence,
Ed

["Cadillac Kid" Greg Surfas 15364]

Ed,
You did not say whether or not your system had been opened and/or left open to the atmosphere.  If it has not been opened, and you have no reason to open it there might be no issues with the refrigerant oil  I say might, because some oil is entrained with the refrigerant vapor as it leaks through the compressor seal and replacement would be required.   
If the system has lain dormant for any time, the oil will adsorb moisture from the air and depending upon the length of time will turn to "gunk" that has to be flushed out.  There are commercially available flushing materials in common use in refrigeration systems.
If the system is in need of flushing, the correct way of ensuring you get all the gunk out is to disconnect the refrigerant lines from the evaporator and the condenser, remove the expansion valve, and flush all the components out individually.
Before reassembly (and a new set of refrigerant hoses would be wise) the addition of the proper quantities of refrigerant oil to each component as instructed in the service manual will allow the system to start up with oil in the proper places.
Typically the condenser takes about 1 ounce, the evaporator about 3 ounces, the dryer/receiver about 2 ounces, and the compressor has a full charge of 6 ounces of oil.  A total charge of about 11 ounces.See your service manual to be sure.  The oil recommended with R-12 is 525 viscosity Mineral oil. You can use mineral oil with R-414b as well.  What I have done on several of my cars is switched to Ester oil, and I did it primarily to check the results in performance and compressor longevity.  You can use it but be careful because Ester Oil is highly Hygroscopic which means you have to be quick and close up the system before it adsorbs moisture from the air.  Mineral oil is probably the best, having been proven for over 100 years in R-12 systems.
IF however you are just replacing the compressor or the oil in it, the proper method is to drain the oil, the way you described and measure the amount of oil you capture.  Replacement, should be the same quantity you remove.
Ed I hope that answers your questions.  If not just let us know.
Greg

[Mike Josephic CLC #3877]

Greg:

Just curious as to why you would recommend R414B as a replacement
for R-12.

As I'm sure you know this product is sold under the name "Hot Shot" and
is actually a blended product made up of a mix of R-22, HCFC 142b, HCFC 124 and
isobutane.

There are a number of reasons that blended products are not the best choice to
use as replacements.  There are also reported compatability issues with this product
with the dessicant normally used in R12 systems.

See the attached link:
http://www.aa1car.com/library/tr497.htm

Mike

["Cadillac Kid" Greg Surfas 15364]

Mike,
If there is something better to replace R-12 as a refrigerant in our Automotive AC systems while providing close to identical performance tell me about it.  ICOR the Manufacturer, began manufacturing R-414b under the nickname of Hot Shot about 30 years ago as a replacement for commercial refrigeration systems and mobile systems such as refrigerated trucks, buses, etc.
I have not seen anything published or even spoken regarding a lack of compatability any component of our AC systems, and have used it successfully in my cars and others for over 6 years,
That's why I recommend it.
I did an article in the Self Starter a few years back regarding the reasons that the "replacement of necessity" for R-12, namely R-134a results in a performance decrease of about 20% so I won't go into that here.  Anyone who has changed from R-12 to R-134a and lives anywhere else than Alaska has stories and complaints regarding their system's lack of performance.  I will go into this subject at the Grand Nationals briefly during my AC Seminar.

For conversation's sake the EU (European Union) has banned the new production of Automotive systems using R-134a starting, I believe in 2012.  The reason is the high "Global Warming Potential" of R-134a is no longer acceptable and the only viable alternative CO-2 was at the mercy of equipment who's sole patent holders were the German Manufacturers.They now have a replacement refrigerant that they are building systems around and that is HFO--1234yf.  This chemical known by it's much more rememberable name of Hydrofluoro-olefin.  The Manufacturer, DuPont (of course) believes that when it goes into production they will be able to market it with a resale price of about $45.00 per pound.

In regards to a blend, the only issues for R-414b is the potential for fractionalization. With a well sealed system, operated enough to keep the compressor seal oiled and working, expectations are for a leakage rate of about 5% per year. That's less than 3 ounces a year.

The simple answer is the product works, sells for less than $10.00 per pound, performs identically to R-12, and mainly keeps me cool in the middle of summertime traffic in southern Texas with NO modifications to my systems whatsoever.
Hope I didn't bore anyone with my rant.
Greg

[Misfit]

Education becomes boring only to the ignorant.

Fins

[Mike Josephic CLC #3877]

Greg:

No -- I don't know of a "better" replacement.  The issue of fractionalization of
a mized bag of components is what I was referring to.  As far as incompatability, I
refer you to the article I referenced.  No need to bore everyone with that here.

However, my preference would be to stay with R12 as long as it's available.  Yes,
you can buy it and it's about $20 per pound.  My advice would be to stock up now
while it's still around.  That's what these systems were designed for.  Why use a
substitute and save a few Dollars and risk issues with compatability with the
refrigerant oil, dessicant and loss of cooling effectiveness?

Yes, I also wrote an article in the "Self-Starter" about this subject 10 years ago when
the issue first surfaced.  I'll be glad to send you a copy but the info is a bit dated
now.

If the "Hot-Shot" product works for you that's great.  I put R12 in my cars as
needed and will continue to do so.

No -- didn't mind your "rant" at all -- always interesting to discuss an issue with
a gentleman who knows the subject.

Best,

Mike

["Cadillac Kid" Greg Surfas 15364]

Mike,
I don't believe I ever said that anything is preferable to R-12 for a system in our old cars that was finely honed around that refrigerant.  The entire issue cam up when R-12 started escalating in price and R-134a was selling for "peanuts".  Many people were unlicensed and since they could not get R-12 and they could get R134a without credentials, they did and tried to "convert" their systems to the later.
I use R-12 in three of my cars, and will continue to do so.  The trials with R-414b was and still is an ongoing experiment.  It has proven highly successful so I am passing on information.
Regarding R-12 at $20.00 per pound, the price for legal R-12 is bit over $30.00 per pound when you buy 30 pounds, or $30.00 per 14 ounce can when you buy it in smaller quantities.  Price in my opinion should be no issue for folks that have to pay $60.00+ to fill our gas tanks, or think nothing of spending hundreds of dollars for rare or reproduction parts to complete our cars.
The point is that at some point in time, after it becomes "priceless", R-12 will become extinct and there has to be something to replace it IF we as a hobby intend to continue and keep our cars operating as they were intended.
By the way, I believe that article on dessicant incompatibility referenced R-12 vs R-22.  In the many years I spent as a refrigeration and air conditioning contractor aside from the physical sizes for systems, both refrigerants were used with the same dessicant.

Greg

[Edward Kenny]

Greg,

In answer to your previous question, I have not opened the AC system in my car at all since I bought the car in 2001, and I have only run the compressor for about 1 minute since that time in order to see if the clutch and clutch coil still work. (They still do).

The vacuum actuator on my STV does not hold vacuum, so replacing either the actuator or the STV with a new actuator is a necessity. Is it possible to remove the actuator and not compromise the unopened AC system?

Ed

[Otto Skorzeny]

Greg, I'm aware of the reduction in efficiency when converting a system from R12 to R134a.

What sort of performance efficiency can one expect from systems that were designed to use 134a from the start? 

["Cadillac Kid" Greg Surfas 15364]

Forrest,
When they designed systems to use R-134a they took into consideration all the performance differences between the two refrigerants and modified the design of the components specifically for that refrigerant.  Just like the engineers (of Old) did with R-12.
Specifically, R-134a operates with a higher "compression ratio" (the difference between the suction and the discharge pressures).
In the case of a refrigeration compressor (reciprocating, piston type) the higher the compression ratio, the lower the efficiency (for a given compressor). The manufacturers modified their compressors for the conditions they were intended to see in operation.
One of the factors helping this equation is the fact that the newer cars that were equipped with R-134a systems are typically much smaller and have much more insulation and sound deadening material in them, thus their cooling requirements have decreased.
The simple answer is that the systems designed for R-134a do not loose any efficiency due to it's use.
Greg

["Cadillac Kid" Greg Surfas 15364]

Ed,
If the vacuum actuator is defective, and it has been so for quite a while, I would suspect that even if the Suction throttling valve is isolated from the power head (I am not sure on yours), the valve itself has a good chanve of needing checking.
How much pressure is in the system itself? Has someone put a set of gages on it whil it runs? What are the running pressures?
Greg

[Otto Skorzeny]

Thanks Greg, I sort of figured that but you are the GoTo Guy for AC questions so it made sense to ask you.

["Cadillac Kid" Greg Surfas 15364]

Anytime Forrest.  It keeps the moths out of my brain.
Greg

[Edward Kenny]

Greg,

I have not had the pressure in the system checked, so I don't know the pressure indexes you mentioned. Yes, the valve is separated from the system; I need to raise the front of the car, set it on jackstands, remove the right front wheel and the inside wheelwell cover (this is per the shop manual) in order to remove the valve.

Ed

["Cadillac Kid" Greg Surfas 15364]

Ed,
I can see what you are up against.  The early "packaging" of AC systems really left something to be desired from the perspective of Maintenance and servicing.  I am still in the dark in regards to whether or not your system has worked recently and if there is refrigerant in the system.  Also, if you have to do all that to get to the valve, do you also have to follow the same steps to access the power head on the valve?
At this point I should also ask what is the physical condition of your refrigerant hoses?
We need to verify the integrity of the refrigeration system.  Is it , does it and can it hold the pressures it will see during operation? 
First things first Ed. Let's see how far we are going to need to go to ensure the finished "product" is a working system.
Greg

[Edward Kenny]

Greg,

I can tell you that the AC system has not run in at least the 9 years that I've owned the car, and I'm betting there is no refrigerant in the system because I pressed both release valves on the compressor and all that came out was a tiny whistle of air... almost no pressure and definitely no refrigerant.

Ed

["Cadillac Kid" Greg Surfas 15364]

Ed,
IF this was my car, here is what I would do;
1. Disconnect and remove all the refrigerant hoses and have replacements made using barrier hose.
2. Remove each of the smaller components (TX Valve, Suction throttling Valve, Compressor) and repair or replace them as required.
3. Flush out the condenser and the evaporator with (commercially available at refrigeration wholesalers) flushing agents to remove all traces of  old oil and any dirt or "gunk" in the system.
4.  Re-assemble the system, adding oil in the quantities recommended to each component and installing a new dryer/receiver.
5. Leak check, evacuate (vacuum pump) and recharge the system with what refrigerant you choose (R-12 or R-414b).
start up and check out the operation of your temperature controls and fan speed.
6. Enjoy many trouble free and cool Summers.

Again, that's what I would do and have done for my cars.

Greg

[Edward Kenny]

THANK YOU GREG!!! That list will help me tremendously.

Ed