AC compressor and 134 conversion

[Pittman]

first off, does anyone know the part # for the compressor. Mine has the front seal out. Also any good places to get one.

Next:

I have to get rid of R12. That stuff is damn near (Texas term) the price of silver. My system was discharged and the R12 captured. What should I do to prepare the system for 134? Any words of advice or caution here?


Thanks for any help

 

[nightdiver]

I asked a pro about it and he said that we need a new pump made for 134 and a new style heat exchanger.
Ok, i got the new pump and ithink im gonna give it a try with the old heat exchanger to see if it works

 

[Pittman]

whoa thats a new one. I though you could use all existing components. I dont think 134 cools as much maybe thats the reason for the exchanger swap.

 

[nightdiver]

The 134 needs viton seals everywhere or it wont last.
When i say heat exchanger i mean the one at the front of the truck that cools the system

 

[InvisiBill]

http://syty.net/phpBB2/viewtopic.php?t=21097
http://syty.net/phpBB2/viewtopic.php?t=23029
http://syty.net/phpBB2/viewtopic.php?t=23403

I got that part number from gmpartsdirect.com. They charge the dealer cost (or whatever) $221 for it, then make their money on the standard 10% shipping or whatever. It's still way cheaper than the $442 retail on the part.

The part swapped in perfectly as far as fit goes. The bearings in the old one totally gave out or something. The shaft and pulley or whatever shifted down and crashed into the outside pulley that the belt rides on. The whole thing was siezed up completely, so the belt couldn't turn at all with that compressor there. I didn't want to mess with the orifice tube and all that junk, though I bought those parts too. It wasn't high enough priority to finish getting fixed, so the new compressor is installed and unplugged for now (drivable but no A/C). Can't tell you anything about the switch to R134 (yet). I did lots of reading, and apparently old R12 parts work a lot better on R134 than new R12 parts. The R12 stuff soaks into the hoses and stuff so the smaller R134 particles don't leak out as much. Brand new R12 parts are more permeable and don't have the R12 oils to seal them up. The review I read said that it might not be the most efficient, but that you should basically be able to just swap in the R134 in place of the R12.

Here's a crappy pic of what happened to me...

You can easily see the black metal ring, which is connected to the triangle part via those riveted strips. Between the rivet and the mounting bolt, you can see the edge of the belt pulley part. It's the silverish part between teh rivet and bolt head there. Because of the angle of the camera, it's sort of crescent-shaped, "disappearing" into the compressor at the bottom. Anyway, if you follow that lighter part up around from the bottom, you can see that there's a notch missing from its roundness right there between the bolt head and rivet. That's what I had to grind out just to get enough clearance for the bolt head to get it out. Yes, the flat side of the bolt head just barely cleared it after I ground off that much.

 

[ItsMyTy]

all the old components will work just fine with 134a in our application. just make sure you change the dryer and orifice tube if you're changing the compressor. with 134a you have to use PAG oil, not the old r12 mineral oil. also, make sure you pull a vacuum for at least 20 minutes (longer is better, to boil off the water and r12 still in the system) before charging with 134a. some people like the variable orifice tubes such as this one http://www.acsource.com/subcatmfgprod.asp?0=273&1=274&2=-1 when doing retrofits because the variable orifice makes up for the less effecient refrigerant 134a.

hth

 

[leroy]

I haven't done a conversion for awhile, but I believe POE oil is preferred to PAG oil for a conversion. IIRC, POE is a little more compatible with any mineral oil that may be left over in the system.

I did a propane conversion once for an experiment. It cooled great.

Jim

 

[Pittman]

Thanks guys

I have a pretty good idea now of what needs to be done.

 

[turbodog]

I've done three conversions, and I agree with ItsMyTy on all counts, although I've never tried the variable orifice tube. Sounds like your compressor is still in one piece, but if anyone else reading had their old compressor fail catastophically, then they need to consider replacing the condensor. Fragments will get in it and break free to destroy your new compressor. Also, partial clogs will decrease efficiency, and with 134 it needs all the condensor capacity, and then some. I have had lousy luck with rebuilt compressors. Bite the bullet and get a new one. NAPA sells them cheaper than the stealer. HTH

 

[turbodog]

I've done three conversions, and I agree with ItsMyTy on all counts, although I've never tried the variable orifice tube. Sounds like your compressor is still in one piece, but if anyone else reading had their old compressor fail catastrophically, then they need to consider replacing the condensor. Fragments will get in it and break free to destroy your new compressor. Also, partial clogs will decrease efficiency, and with 134 it needs all the condensor capacity, and then some. I have had lousy luck with rebuilt compressors. Bite the bullet and get a new one. NAPA sells them cheaper than the stealer. HTH

 

[syclonekid43]

i changed mine oever to 134 all i did was change the evaporated and put the 134 in. it works mint. i think it works better now than the r12