Drewster67

I'd say we have about three months left of cool weather.

I would like to start planning converting my a/c system from R12 to 134 and I have a couple of questions.

First, I would like to convert over because of the cost factor - r12@50lb or 134@8lb, plus it's better for our planet.

Will I need a different compressor?. If not, who sells a conversion kit?. Is this a DIY project. (a/c system depleted already). Anything in general I should be aware of?.

Thanks in advance

WallyP

If you have a Costco, BJ's or Sam's warehouse nearby, they currently have R-134a for $60 for a 30 lb. bottle, and $24 for a twelve-can case of 12 oz cans.

No, you don't need a new compressor.

You do need to change all of the O-rings, and the receiver/dryer.

There are mixed feelings about changne the oil in the compressor. You MUST use different oil (POE), the question is whether or not to remove the oil mineral oil from the compressor.

PRO Changing:
If you leave the mineral oil in the compressor, you will have too much oil in the system, which cuts efficiency.
The old mineral oil will eventually collect in the bottom of the evaporator and condensor, lowering efficiency.

PRO Leaving:
The mineral oil is a better lubricant, and will help the compressor (as long as it stay in there).
It makes the job a LOT easier.

Most dealer changeovers now leave the oil in the compressor.

You will need a GOOD vacuum pump, a leak detector and a set of R-134a gauges.

Drewster67

Walley - If I send you my compressor, can your specialists do the conversion for me.

Thanks for the reply

Dozman

Sorry for being long winded...


Drew,
I do believe that what Wally means by o-rings are the orings that are in between the hoses and drier condensor and such, not inside the compressor itself.

Wally,

I have not purchased refrigerants at Costco or places like this. Can you purchase R134A without a refrigerant license from the businesses you listed?

If, someone in the area can drive to the area I live in, I can provide and charge your a/c system considerably less than the cost for what the refrigerants are sold for. Since I work in the commercial/industrial refrigeration field I have ability to purchase the refrigerants far below the rates stated. I have about 150lbs of R134A and about 70 lbs of R12 in my garage. For such personal needs.

I am thinking if I go to Sharks in the mountains, maybe I should bring some refrigerant with me to save other's some cost here. Does anyone think this is a good idea or not?


I can understand the statement converting to R134A due to cost, but not that it's better for the environment.

R-134A better for the planet and for humans. Well this is open for debate. According to the Montreal Protocol you are correct. According to most of the scientific studies you are correct.

With the coincedence to time restraints of patents for the refrigerants expiring and the studies coming out like The Montreal Protocol are the studies tainted? Seems at times the Duponts, Isceons and Refrons (refrigerant manufacturer's) have Billions of dollars to loose after their patents expire. Is R12 really that bad as compared to R134A for the environment? The findings how bad a refrigerant effects the environment are still theoretical. There are no hard facts that the earths ozone does react how the scientists suggest. Too many factors constantly changing, wind, volcanoes, major fires in the world, manufacturing etc... The information taken for study of the whole in the ozone issue was taken from what the last say 60-75 years. Could the contributing factors to the ozone be more from manufacturing, coal burning and such? But taking into account that R-134A will be replaced as well, it is not good for the ozone.

John D

Drewster67

What's so different between R12 and R134a anyway?
Isn't 134a "warmer" than R12?.

Thanks Again

WallyP

As John D said, there is really no conversion to be done on the compressor, with the possible exception of pulling a drain plug and changing the lubricating oil, and changing a couple of O-rings where the lines attach.

Every joint in the system is sealed with 15-20 year old O-rings that are made of an elastomer that isn't really compatible with the POE oil for the R-134a.

The O-rings are leaking now, and will leak more with the new refrigerant. Not much money, but a lot of work - but it is worth it.

It really doesn't make much difference in performance which refrigerant that you use. The actual performance of a 928 system is much more a function of how tight the vacuum system is, and how well the system works, than of which refrigerant is used.

You only need to get the evaporators to 32-34 deg F, and either refrigerant can do that easily. The only real performance hit for R-134a is that it requires a larger condensor than does R-12. Luckily, the condensor on the 928 is a large unit. On a few cars, such as the Chryler minivans, the condensor is so small that R-134a just won't work.

Drewster67

Wally and Dozman -

Thank you for the information - I learned something new today so I guess that makes it a good day!.

If you learn something new each day, your a little closer to learning something else new. The beauty of it all is...you just don't know it.

Greg86andahalf

Drewster,

there is much info on A/C conversions in the archives. I remember posting alot of stuff in the summer.

Go to griffiths.com and read the info on conversions.

There is a DIY way to do the conversion, (system MUST be vacuumed down, which is not the same as evacuating, the corner gas station can do for you)but PLEASE don't buy a conversion kit for $30 at the auto parts store which promises a "solution in a box" They are death kits. Those who will argue that they did the quick conversion, dumping R134 over whatever was in the system and not vacuuming the sytem down, with an over-the-counter R134 kit and have had success, I say give it time. You'll see.

I did a compressor rebuild, replaced drier, expansion valve, installed barrier hoses and o-rings. I kept the system R-12 which I bought for between $14 and $20/lb. on ebay with my 609 license. In one season, I have not lost any freon and have not had to top it off. I am a advocate of keeping a system R-12 and not converting.

Doz,

I have an electronic leak snifter for R12 and R134A, a U/V dye kit, quality vacuum pump and most everything else for automotive A/C except a recovery system. Being that I live in B.F. Egypt, it would be cool to find a central location and a shop with power and do some leak finding and recharging for owners. Dave and Wally could probably sell some parts like diers, o-rings, etc.

There seems to be a need for A/C help, I'd be interested in helping.
Greg

John.

I used an Interdynamics conversion kit on my 81, just added the oil and then blew the gas in to it. I did chenge the Rd and the Exp valve. It works well.

Drewster67

Greg -

Thanks for the info.

I would rather keep the system R12 as well but I have a little problem.

The average temperature during the summer is 111 degrees - give or take a few - and summer lasts roughly six months out of the year.

The A/C vendors have a gold mine of a business and they can charge a mint for services and materials.

Last summer, before I bought my shark, I owned my 87 924s and I needed some a/c work done. First, there was a leak down test - 150.00 - So, after the test,the Remaining freon needed to be evacuated out-75.00 -repair of the line, - 100.00. 350.00 already and the system not even fixed. Then comes the freon - 60.00 a lb and 30.00 oz.required.

By the time it all said and done - roughly 500.00 just to have the system checked, repaired and filled.

Mind you, the evacuation price was unjust as the leak down test.

With each passing summer, R12 prices increase. In order to have my system up and running (and if I take it a shop), I'm looking at half a grand easy.

Even if I do the work myself - Freon will be too expensive.

Question - what did you mean by "death Kits" - Would I be at risk to bodily harm if I used the conversion kit?.

I want to do this the best, economical and most practical way, r134a seems the best bet.

I will definately look into the archives and thank you for the reply!.

Greg86andahalf

Drewster,

Death kits refers to death of your AC system, not death to you.

Reasons include: mixing of incompatable oils (compressor death, moisture retension), mixing of freon types, residual moisture and air left in system (air does not compress in system, moisture can cause acid to eat through system from the inside out), use of R134 in system without changing O-rings to a R134 compatible type (leaks), overcharging of system (no explination needed), the kits don't come with a R134 calibrated low pressure cut-off switch which is recommended when using R134 in a R12 system. I can go on.

The kits sold in stores look tempting, but your system will suffer. Go to aircondition.com and read the webbord. The stories are amazing. Stuff like "used a $30 conversion kit, now my compressor sounds like a jackhammer" Good reading.

There are ways to do a quality R134 conversion, but a $30 kit won't do it.

Here is one good alternative: Go to griffiths.com He has a kit for changing a R12 928 to a R134 using a new compressor, barrier hoses and assorted parts. The price, as I recall was quite reasonable. As an added bonus, I recall Dave at 928 specialists posting that he sells the griffith's kit for a little less money that griffith's does. This is the complete solution. You can do all the work yourself and then have a gas station vacuum the system down (vac for a couple of hours, then a 30 min hold test) then charge R134 into th vacuum. You're gonna spend $800 or so by the time you're done, but you will have a R134 system with alot of new parts and a future. You may never experience quite the same cooling with a R-134 retro on a R-12 system (many debates on that one) but I think you can get it good with a griffiths kit.

BTW, my parts cost was about $500 on my R12 rebuild w/barier hoses, drier, expansion valve, O-rings. My system cools to 36 degrees and does not leak. I have about 15 cans of R-12 on hand. When (and if) that's used up, or if my compressor bites the dust, I'll re-evaluate a conversion. Maybe by that time, there will be a new freon which acts more like R12 in R12 systems.

BTW, there is no good "drop in replacement" for R12. Please don't even bother looking at blends, propane, butane, R22, autofrost, etc. Some of that stuff quite flamable and dangerous and could lead to your death.

Greg

Drewster67

36 degrees is like Heaven in the Desert. Beleive me, when it's 111 outside - It's about 160-170 inside your car with the windows up.

At least have some time before I figure out what I'm going to do. Thanks again for the information -

BTW - Interested in selling 30. oz of Freon?.

Dozman

Greg,

I do have the very high end sniffer, I also have three other sniffers that are on the lower end. Your right with the refrigerants prices being artificially inflated, there is a need for our group to be able to rely on a source for expertise like a/c.

John D