Some Rudimentary AC Questions

[Paulporsche]

I'm about to replace the AC on my 77 with new components from Griffith's. Before I start tearing into things, I would like some advice.

1.Does the stock v belt, 900192750 12.5 x 1100, work with the new Kuehl compressor? The car originally had a York.

2. Some of the copper gaskets that fit into the refrigerant line flared connectors seem to be NLA per our host. Aside from Porsche parts suppliers and dealers, are these generic parts that would be readily available from auto AC suppliers? They are shown in PET as 7/16, 5/8", 3/4" and 7/8" sizes.

3.When the original AC was removed, the hoses remained in place. Is the best practice to attach the new to the old and pull them through, or do the new ones easily fit into place? If pulled through, should the new lines go from front to back or from back to front? Or does it matter?

4. Is the square blower relay, 91161510301, located in the smuggler's box? If not, where?

Thanks. LOL. I'll probably have more once I get into it.

[GH85Carrera]

If you are getting the Griffith's upgrade kit, just read the fantastic instruction he provides. He writes instructions like they should be done for all products. Clear, step by step how to do it. Read them cover to cover, then start over and just follow his steps.

If you have a specific question, email or call Charlie, and he will talk to you. The instructions will answer most any question you can think up. He revises them as new customers go through the process and over the many years he has sold a lot of systems.

He will send your instructions that cover the steps for what you bought from him.

Not one part of the entrire process is difficult, just time consuming for a super slow "mechanic" like me. The only part that is tricky is getting the refrigerant charge done properly. The vacuum and charge are the parts that require some special tools and equipment. The one bit of guidance I can tell you is you can't ever have too good of a vacuum, or too much moisture removed. I use the total over kill excessive vacuum procedure. Multiple hours of vacuum, pressurize with dry nitrogen, long vacuum more nitrogen, long overnight vacuum using a micron gauge to know just how good is the vacuum, then charge. The manifold gauges can't really show you the vacuum level, you need a micron gauge.

[Coastr]

ok this is my second go at answering as the forum ate my first. I'm doing this job right now so can answer some of the questions.
1) I'm not sure, but I bought the standard size and we'll see if it fits
2) Yes, they are a standard size fitting available wherever AC service parts are sold (amazon has kits)
3) You don't need to use a hose to pull the other hose - in fact the bent ends of them make it a bit hard to do so. Take photos of key routing points like the receiver dryer and front condenser (multiple hoses/looms/pipes) and pull the old one out, then put the new one in. Keep your p-clamps in the same order you take them off so you get an exact fit of where they came from.
4) There is no relay in the smugglers box. I think the one you are looking for is near the fuse box.

[GH85Carrera]

Maybe on the 77 there is no relay in the smuggler's box. But on my 85 there sure is. It is on the passenger side of the smuggler's box.

[Paulporsche]

Thanks Glen and Coastr.

BTW Coastr, Griffith's instructions say to use the original size belt. The instructions also mention a relay in the smuggler's box but I haven't verified this yet on my car.

[Tommy Z]

Hi Paul, I'll chime in as I completed my Griffiths install this summer.

1) Yup. My brand new original belt worked just fine on the new Kuehl Compressor.

2) I can't speak for the hose set that Griffith's would provide for a 77' but the kit for my 79' came with everything I needed. The only flared fittings are at the connection between existing condensers and new Kuehl hoses. I don't recall using any copper gaskets. The new fitting went directly on to the old condenser fittings. All the new hoses came with properly sized O-rings from Griffiths.

3) Just follow the instructions from Griffiths. They are really well done. I would recommend you read them all the way through and then read them again. I made a few mistakes that required redoing something just because I didn't read carefully enough.

The routing of the hoses from the back of the car to the evaporator box and front condenser were the hardest part. I attached a thin rope to each of the old ones as I pulled them out so that I could attach something to the new hoses to help guide them through. Griffiths recommends pulling them both through that space behind the water bottle together but I had more luck doing them separately. The instructions are very clear and if you follow them you will have no problems. If you have questions Charlie is super knowledgeable and patient. I'm pretty sure I went overboard with my questions and probably wore out my welcome LoL but he is always willing to help.

4)In my 79' the relay was located in the smuggler box on the passenger side. Griffiths will provide you with a new one depending on how far you decided to go.

GH85Carrera is giving you important advice above in regards to the charging of the system. I have been struggling with mine since I completed the install. Do not expect to be able to bring it to a good automotive AC shop and hope for good results. I have been to two of them so far and things are much better but I want Glenn's results and I'm convinced his extended vacuum and nitrogen filling procedure is the way to go. I have had to pause my AC work for a while to address some suspension issues that came up and with the weather finally starting to cool the timing helps. I have made arrangements to borrow my AC sub-contractors vacuum pump and I'll track down a nitrogen bottle so I can follow Glenn's system in the next few weeks but I know when I get the charge done myself, the proper way, the system will perform just as it's intended to. Good Luck!

[Paulporsche]

Thanks Tommy. My car only has a rear condenser so it may make pulling that line a little easier.

The PET shows multiple copper "gaskets" in hose connections. They are cupped and look like the enclosed pic. For my single rear condenser setup it looks like I need 5 @ 5/8", 4 @ 3/4", 2 @ 7/8" and 1 @ 7/16". I'll check with Charlie. Maybe his hoses don't need these things.

The PET also shows O rings, which I have in the kit.

I see that I will need a 7/16 and a 3/4 for the TEV when I flush out the evaporator.

[pavegeno]

Good luck to you! 13 years with my Griff's system on my 88 Cab and it still pumps out low 30s and keeps me cool in Alabama. Griff is great for customer service.

[Coastr]

Since reading your post I have been diving into copper gaskets for flare fittings. I don’t recall reading them in the Griffiths instructions or seeing them in the kit. Maybe not necessary? Reusing any of the old condensers means having flare fittings, so curious what others have found.

[Tremelune]

Originally Posted by Tommy Z

Do not expect to be able to bring it to a good automotive AC shop and hope for good results. I have been to two of them so far and things are much better but I want Glenn's results and I'm convinced his extended vacuum and nitrogen filling procedure is the way to go.

What, what? Can't you tell them to do this? I have plans to install AC in my car, and I reeeally don't want to deal with the fill. I just want an expert to do it, and do it as well as it can be done.

[GH85Carrera]

You can just see the edge of the relay on the left of my smuggler's box.

One thing with the Griffith's kit, he provides EVERY part you will need. Down to the last screw, zip tie, and washer. All you have to provide is the tools and labor to install it. Follow the directions step by step. Easy.

I know I sound like a salesman for him sometimes. I do not receive anything from Charlie I don't pay for, and I sing his praises only because since 2006 when I put my system in, it has been just wonderful, and his stuff simply works. I have zero experience with other AC systems out there for the 911 so I can't speak to their cooling or long lasting ability.

With his system I have driven to 41 states and Canada. If you want to have a test of AC, drive from Oklahoma City to Key West Florida and back in late July. Coming back to OKC I was driving due west, with the afternoon sun shining on my chest on a 100+ degree day in Arkansas and I had to turn the temp UP because I was getting cold. I had been driving for 8 or 9 hours by then on a 12 hour drive from Montgomery, AL to OKC.

[Tommy Z]

Originally Posted by Tremelune

What, what? Can't you tell them to do this? I have plans to install AC in my car, and I reeeally don't want to deal with the fill. I just want an expert to do it, and do it as well as it can be done.

Tremelune, I doubt highly that you will have the same issues in LA I had down here in south west Florida. I would absolutely look for an independent Porsche shop that has experience with the Kuehl system. I would also highly recommend that you follow the instructions to flush the condensers before charging the system. My shop compressor died on me and I was unable to flush them myself. I asked the charging shop to do it before they charged the system and they did not. I really believe this is my biggest issue. The shop also did not put a vacuum on the system for more than a few minutes and I believe this is the source of my less than perfect results. Unfortunately I was not able to stand over them while they did the work and I really should have.

There are too many drivers out there enjoying the AC in their classic 911's for anyone to doubt the efficacy of the Griffiths system but you do have to take some personal responsibility to make sure the charging is done properly. This is why I am going to at least tackle the flushing of my condensers and the vacuum of the system. Glenn even spoke about adding nitrogen to the system in order to ensure there is zero moisture and I plan to do that as well. I may take it somewhere to be charged after that or perhaps I will suck it up and buy a large can and try and fill it at home. I bought a set of AC gauges so it should go smoothly. Don't let any of this dissuade you from pulling the trigger on a Griffiths system. Even the less effective version I am currently running made the car usable year round and that is priceless. I am a complete newbie when it comes to wrenching and took immense pride and pleasure in doing the install myself but like anything that you are new at there are learning curves. I will get my system dialed in and when I do it will be even more rewarding.

Good Luck!

[Paulporsche]

Glen,

Nice looking installation and car!

Did you flush out your evaporator? If so, did you remove it from the box?

LOL! I got a response from Charlie to some questions I had about O rings replacing copper washers.. He told me to read the instructions!
I'm definitely doing that of course. I didn't get instructions for every hose but it seems self evident, and on the website, there are notations about various hose fittings and what they do or don't require. Flare fittings, eg don't require gaskets or O rings.

It turns out the copper washers I mentioned as seen in PET seem to be replaced by the O rings, although I don't have as many O rings in the kit as was the number of copper gaskets, so I'll have to see what happens during installation. The photo on the website shows 10 O rings but I only see 4 in my package. I'm going to do a dry fit mockup before installation in the car. He said to get in touch with him as I moved through it.

He did mention that the 2 copper gaskets to the TEV are to be retained (or replaced with same) however. Looks like these don't get replaced with O rings. Did you reuse the existing ones?

[Coastr]

Copper washers are not o-rings. O-rings are for o-ring fittings and copper washers are for flare fittings. I’d ask again for the specific hose/fitting (ie new hose old condenser)

I take back what I said earlier about the relay. Looking in the wrong spot per photo above.

Re the nitrogen - been re-reading my copy of hack mechanic guide to vintage air (quite good!) - nitrogen tests system pressure better than vacuum, also chases air/moisture out. As a diy you should bite the bullet on gauges and vac pump, or at least borrow from local parts store. You don’t need to fill but if you’ve satisfied yourself it holds pressure and a deep vacuum overnight fill will work great.

Ultimately only deep pockets and good relationships can get the right results from a shop. It’s definitely possible but not common to get good results from paying someone to do it for you.

[GH85Carrera]

Paul, I have replaced the evaporator and the blower motor. The evaporator was replaced when I did the original conversion long ago. The improved evaporator with a new expansion valve is likely a big part of my great AC performance. And Charlie's hurricane blower is a nice improvement.

My advice is to carefully read and study his instructions front to back. Then when you are ready to tackle the installation, follow them step by step in the order he has them written. His instructions are very good to amazing level of how instructions should be written. Make notes in them as you go, and file them away when done for future work.



It is almost embarrassing how gross my old original evaporator was. There was no doubt it needed to be replaced. I planned on replacing it even before I pull it out, and was happy I had his new one to go back in.

One of the problems that was easy to fix was my drain tube was partially blocked. It would drip water for a long time before the repair. Now it leaves a big puddle of water if it is a humid day.

[thsupernge]

Great advice, thanks for that Glen!

[Discseven]

Paul... you didn't ask about oil but it's important topic in terms of AC's cooling performance and endurance. Too much is no good for cooling and too little ends up in a "black death" of compressor (due to lacking lubrication.) Only way to know what the oil level is in AC system is to flush the whole of it excluding the TXV and compressor. If replacing hoses with new, that eliminates flushing the hoses of course. Compressor is emptied of oil. Forgot what the spec is for what quantity of oil remains in compressor when it's emptied but there is some. For a 3 condenser system (2 stock + rear fender) oil total is 5.5-6 fl ozs. The lot of it going into the compressor (minus what remains in comp when its emptied.)

Having experimented with AC for years, I found the best results coming with---among other things---having pulled a vacuum for 12+ hours. (Commercial shop that pulls a 15 minute vacuum prior to charging does a customer no favors.) Always fresh vacuum pump oil in pump prior to using it. This provides the best seal for the suction process. And so the pump does not draw AC oil out of compressor when vacuum is being pulled, elevate vacuum pump and suction hose well above compressor.
.

[Paulporsche]

Thanks Coastr, Glen and Karl.

I've been doing further reading including on the Griffiths website, which states several times that no crush washers are needed with Kuehl barrier free hoses with flange fittings. I have some of these, including on the rear condenser. Although he did say that I might need new crush washers for the flanged factory TEV connection. Obviously O rings are needed for the other type of fittings.