I gots cold air, cool he he

sammyg2 · 08-17-2003, 11:18 AM

I just finished driving my 911 SC with a/c for the frist time since I bought it.
The rear condensor had a hole in it so I replaced it with a used one from e-bay (I got lucky). Then I evacuated the system with my harbor freight venturi vacuum pump ($9.95) and then installed the R132A fittings and charged it with oil and refrigerant, then pulled the little plastic vent thingie behind the center console.
It blows cold. Not as cold as my truck but cold enough. I was very conservatice with the amount of refrigerant I added because my gauges aren't here yet (on order). When htey get here I'll try to optimize the system. I need a thermometer to measure the vent temperature but right now i'd guess it's in the high 40's.
Much better than driving around on 95 degree heat with both windows rolled down.
I'm sure I did several things wrong but it works. I'm a happy camper.

MY83SC · 08-17-2003, 02:35 PM

Just a quick ??? Where did you buy your HF VV pump from??? For that price...I'd like to get one and do the A/C job on my car also...Thanks in advance!!!

JeremyD · JeremyD's Garage

Quote:

Then I evacuated the system with my harbor freight venturi vacuum pump ($9.95)

MY83SC · 03:10 PM

OK...Did a search....I found a local HF outlet a few miles from the house.....I didnt realize they were a store front....Thought it was just a brand name...TY

sammyg2 · 08-17-2003, 04:06 PM

The harbor freight website advertises them for $13.99 but I went into the store and paid $9.99.
BTW this is the same vacuum pump being sold on e-bay left and right for anywhere between $16 and $25.

ruf-porsche · ruf-porsche's Garage

eBay always a sucker willing to part with his money.

PeteT · 08-17-2003, 05:22 PM

Sammy,
What type of hose did you use on the HF vacuum pump to the compressor? I have one but haven't taken the time to figure out the fitting. BTW good job on getting the SC blowing at least somewhat cold air!!!
Thanks
Pete

jmohn · jmohn's Garage

Quote:

Originally posted by sammyg2
......SNIP......conservatice with the amount of refrigerant I added because my gauges aren't here yet (on order). When htey get here I'll try to optimize the system. I need a thermometer to measure the vent temperature but right now i'd guess it's in the high 40's.
.......SNIP.....

Just a tip, forget the gauges (or just use them for informational purposes), they're really only good for getting the charge "close" to the right amount. If you're really getting vent temp's in the upper forties your already close (DO check with a thermeter). Add a little more 134a and check vent temps (allow system to stabalize after adding 134a, takes about 10-20 minutes), then add again and re-check. When the temp at the vent stops dropping you're at optimal charge. This really is the most accurate method. Optimal charge amounts vary from system to system and 134a is much less forgiving of over\under charging than R12 was.

Good luck,

Jerry M
'78 SC

turbo6bar · 08-17-2003, 06:26 PM

Hey, Sammy. I got yer cold air right here. The past two days, A/C in the SC has been so cold, the vents literally drip with condensation. Also, I had to turn the vents upwards to keep my hands from freezing to the steering wheel. What the 911 A/C really needs is more vents in a better position. The air coming out of the vents is so cold, but it is all focused in one area. Hmmm, I have an idea...

Can one use the center tunnel as an A/C vent? I recall the tunnel is sealed on both ends, but it's been a while since crawling under a 911.

Good job with the A/C. A 911 with A/C is great. Temps here are 95 with high humidity. Today, I saw another 911 with the windows down. His ride was quick, but I bet the driver was sweaty as a hog in Texas.

Jurgen

sammyg2 · 08-17-2003, 07:45 PM

On the air vac vacuum pump I took an old hose from one of those screw-onto-the-can recharge things and cut off the end that attaches to the can. then I replaced the fitting on the vacuum pump with an 1/8" NPT fitting with standard hose barb on hte other. One hose clamp and it was ready to go.

the biggest PITA was the fact that my compressor was too close to the sheet metal to get the lower hose on the fitting. I had to loosen up the compressor and slide it towards the fan in order to install the hose, then re-adjust it before starting the engine. Repeat every time and for when I had to remove the hose. But I got real good at it.

GB83SC · 08-18-2003, 04:51 AM

Hey Sam, Two questions for you.
Once you evacuated the system and there is nothing in it, does the SC have a low freon switch that turns off the compressor when low ? (ie.Chevy has them on the dryer) you have to jump it, in order to get the compressor to kick on to get freon back into the system.
The second question is the low suction side- there are two hoses on the compressor the fater hose is the suction LOW side?
Thanks in advance.

ruf-porsche · ruf-porsche's Garage

GB83SC

Unless you or the previous owner upgrade the compressor to the P car, you have the old York Compressor that came as standard equipment with all factory a/c P car for that year. The York compressor does not have shraeder valve (Valve similar to tire valves or bicycle valves) but has stem valves.

Do a search on this board for "stem valve york".

The factory system does not have a low pressure or high pressure cut off switch.

GB83SC · 08-18-2003, 06:19 AM

The compressor was changed out by the PO, the only label on it is TAMA J639 its made in Japan. The system is barely working (almost three years without a charge) So I have to get some juice to it.
Thanks for the help.

sammyg2 · 08-18-2003, 07:07 AM

Yup, mine's an OEM york, the suction side is the lower port. The suction side of the compressor pulls from the evaporator in the front of the car through a larger diameter hose. The discharge side has a smaller hose and goes to the condensor on the engine lid. Don't get em mixed up, bad things can happen.
No sut-off switch on my compressor but I may add a high/low pressure shut off switch after I get my gauges.

Pete000 · 08-18-2003, 12:42 PM

When you evacuate the ac system with the Harbor Freight pump (which I just ordered) do you repalce the oil? Or do you just ad the R134 which I purchaced a retro fit kit and it came with the hose to put it in and line fitting adaptor. I am also going to replace the receiver dryier which I hear is aslo a recomeded thing to do when you convert.

scottb · 08-18-2003, 12:50 PM

Sammy: What kind of vacuum reading did you get on the gauge? Anything close to 29?

Thanks.

ruf-porsche · ruf-porsche's Garage

Any time you replace parts in an a/c system, pour out the oil that is still in the items that you are replacing in a glass container that can measure the amount of oil. Pour back in the same amount of oil into the new part. If your compressor didn't suffer the black death or if you are not changing the type of refrigerant that is in the system, you can resuse the oil provided you did not contaminate the oil. If you don't replace the oil, the system will be low on oil and eventually suffer black death.

RickM · RickM's Garage

From what I understand it is probably best to use new oil after opening and draining the system.

sammyg2 · 08-18-2003, 01:12 PM

I was told that the R12 oil and the R134 oil were not compatible. I blew through the system to try and remove as much oil as possible. I added the R134 oil before adding the new refrigerant.
BTW I bought a thermometer today and measured the vent temperatures, I was way off. 58 degrees with the fan running full blast, 56 with it on low setting.
As soon as my new gauges get here i'll try to improve it a little more.

ruf-porsche · ruf-porsche's Garage

If you have new oil to refill the a/c system by all means refill with new oil, however since most parts on an a/c system with the exception of the compressor only reguires 2 oz. or less of oil you will need to buy a bottle of refrigerant oil just for a couple of ounces. The problem is that you need to measure exactly how much oil was remove from the system and not x amount of oil per item replace.