A/C???

[J_B]

Hello im new to this forum and i have been thinking of doing a sbc 350

v-8240z. Though im a novice in fixing up cars i just wanted to aska question. When you swap engines, will you still have your a/c in the car? Or do i you have to modify that? Thanks alot...Love the site!

 

Joseph

(v-8 240z/260z)--in the future

[Mike C]

Like everything else, AC is covered in the JTR manual. Usually requires using your donors GM compressor and having custom hoses made. You should get a book on AC and learn differences between orifice and valve type systems and their integral pressure switches to see which will work best for your application depending on your donor vehicles year and style of AC system.

[Pellius]

The Datsun A/C system is pretty straight-forward. I don't see any reason why you can't make a custom bracket and simply mount your Datsun (Mitsubishi) compressor to the Chevy motor. However, my experience has been that the Datsun A/C system just doesn't cool the cabin very well.

 

For my car, I'm saving up for a 100% aftermarket kit. Before I buy, I'll ask around for other experiences, but right now I have my eye on a kit by Hot Rod Air. The kit is around 800 bux, but it comes with all the components (except freon and a vacuum pump) and an integrated under-dash unit housing the evaporator, heater core, fan unit, and all the venting controls. It is in a box that is something like 12x12x20 or so. It should fit cleanly behind the glove box, and no more push/pull cables! The controls unit look nice and modern, and fairly tasteful.

 

I didn't set out to pitch the product. Those are just the things that I noticed when I was shopping around. Anyway, if your Z has A/C, just make a mount for the compressor. I don't think I would try to tackle transplanting a system from a different car, though. Dunno if this helps.

[Mike C]

Nissan never had a "factory" AC 240. All of the systems were dealer installed and most had the York compressor. They make a great offroad air compressor for a 4x4 but aren't the ticket for air conditioning. Either of the GM styles (axial or rotary) work much better. Ditto the later Nissan AC systems.

[80LS1T]

Another thing with the old Datsun systems is that they are R12 not R134a refrigerant. This means that you will need special "barrier" hoses and lines if you want to convert over to R134a. This is because the R134a molecules(sp?) are much smaller than the R12 and if you just put R134a in an R12 system it will just go right through the hoses. This can be very expensive to "change over"! I almost did this conversion on a 197x Corvette but after I told the guy that it was going to cost $800+ to do the job right he said he would have to wait on it.

 

Not only is that a problem but try finding a shop that does R12 stuff! The EPA(or who ever monitors the shops for A/C stuff) has really cracked down on "shade tree" machanics in the A/C department, so the R12 stuff is becoming extinct because it is just too much work to keep up with the EPA regualtions rather than just do the R134a stuff. I personally don't know of any shops that do R12 anymore, it's just too much of a hassel to work on.

 

My points being, if you want A/C go with the Chevy stuff and R134a because in the long run it is much cheaper and there will always be parts availble!

 

 

Guy

[Pellius]

Just to add my two cents: I did a 134a conversion in my 240z by simply pumping out the old freon, attaching the 134a adaptors for the charging valves, and putting in the "conversion" oil and freon that came in the $30 conversion kit. I didn't even change the drier. It worked fine for something like 4 years with no recharging. (I have recently had some problems, but I think they are due to the orifice assembly) I converted a Celica the same way with similar results. Kinda cheap, but, well, kinda cheap.

 

Even if you need to recharge once in a while, a 12oz can of 134a goes for like 2 or 3 bux (around here).

 

If you can hunt up a pump, it might be worth the price of a cheap conversion kit to give it a try, especially if you have no cool right now. An A/C shop should be able to pump your system down.

 

BTW, changing the rubber hoses shouldn't be too tough - on my 240 there are only 4 of 'em (as I recall), and you can pretty easily reach both ends of each. You'll prolly have to cut the old hoses off of the hose fittings.

 

One last thing. You might consider having a shop look at your system and give you an estimate. Since the system is an add-on (EZ access to everything), it might be cheaper to convert than you think. All that said, I still vote for a domestic 134a system. New everything will outperform and outlast fixing what you've got.

[Guest benjlv]

first post here, but i had to post...

 

your R12 rubber hoses will be fine. The mineral oil in the system gets into the rubber and seals them up. So as long as R12/mineral oil has been in the system which it has the R-134a wont get out.

 

The $30 el-cheapo kits are a mixed outcome. While cheap they tend to be below performance becuase you dont remove the old oil from the system which hurts heat transfer. Also the old oil in the system becomes jelled up...and goopy in a R-134a enviroment, which can lead to compresser failure in many cases, or clogged components such as the expansion valve. The recieiver dryer is reccomended to be repplaced as the material inside the old R12 dryers is not compatable with R-134a. The R-134a eats away at it, but I have heard few examples of this problem, but if i were to spend the money and time I would just replace it.

 

The proper way to retrofit is to flush the old oil out. Replace the dryer, use R-134a oil, replave o-rings with r-134a ones, change the service ports to r-134a.... and pull a vaccum and fill it up.

 

there are corners that people often cut with mixed results.

 

Another option is to use hydrocarbons as a refrigerent. Its a mix of butane and propane with a nastey smelling odor for detection. I know what youre thinking "those are flammable" but in reallity so is R-134a and the mix of propane and butane has a higher flash temperature. There have been rumors, but nothing proven in any accidents or explosions involving HC use in A/C.

 

The HCs are a direct drop into a R12 system. You dont need to pull a vacuum, but it is reccomended. The dryer doesnt matter since HCs dont combine with water to form acid. The HCs have a lower boil temp than R12 so they actually improve the A/Cs efficiency although you may need to adjust the propane to butane mix and or the explansion valve. Theres a guy on zcar.com thats doing the conversion right now...and I will someday as well.

 

http://www.greenchill.org and http://www.aircondition.com are good areas to get more info on HCs. Although i must mention that they are currently illegal in many states but there are legal loop holes in which a R-134a system can be converted to HCs, so that way you can slap R-134a service ports on it and say you converted twice.

[Dan Juday]

Benjlv, Welcome to hybrid. Sounds like you know your AC. Your expertise will be a welcome addition here. I'm an AC mechanic myself but I work on commercial building systems, mostly R-22. I don't work on auto AC. That's my story and I'm sticking to it. "Yes, you're my friend. No, I won't fix your AC"

 

One warning about HC's. I know of an auto mechanic that was seriously burned when a car he was working on blew an AC hose and the propane, installed in the system illegally, ignited and shot a flame in his face like a blow torch.

 

In my book it's not worth the liability exposure. If I were to even suggest swapping a non EPA approved refrigarant into one of my clients systems I risk losing my EPA license. If someone got hurt because of it, I'd go to jail.

[Guest silverbullet]

A quick dumb question for you A/C guys, I plan on repairing the stock A/C in my 77 soon and am going to replace the dryer/reciever and hoses, do most shops that work on auto A/C also make hoses?

[Guest Want aZ]

Just a novice on A/C systems, but I thought there was a difference in Operating Pressures between R12 and R134a, Ive thought about doing a R134a Conversion on my truck but its a bit cost prohibitive, as I was going to change the drier, hoses, and flush entire system, could probably use a compressor too as mine is making some noise. But I will stick with what I have for now. Even though R12 here in the USA is like $$$. In Panama its still like $1.50 a can, but you cant bring it back though

[Sumo]

I changed my A/C from R12 to 134 with no problems on a 78 Skylark with stock hoses. All you really have to be careful of is to flush the system thoroughly of the old crud and stuff. The only reason why i converted is because my compressor crapped out and i took it as an opportunity to change over. Also make sure you use the silicone O-rings that are sometimes provided when changing over. When time came to vacuum and charge the system, i went to the professional and he only put in 80% charge and it cooled great, he charged me only $35 to vacuum and charge it (i supply the 134). If you are going to do this on a Z the pro's recommend changing the condenser to a larger one since the 134 does create more heat.

[Guest benjlv]

Benjlv' date=' Welcome to hybrid. Sounds like you know your AC. Your expertise will be a welcome addition here. I'm an AC mechanic myself but I work on commercial building systems, mostly R-22. I don't work on auto AC. That's my story and I'm sticking to it. "Yes, you're my friend. No, I won't fix your AC"

 

One warning about HC's. I know of an auto mechanic that was seriously burned when a car he was working on blew an AC hose and the propane, installed in the system illegally, ignited and shot a flame in his face like a blow torch.

 

In my book it's not worth the liability exposure. If I were to even suggest swapping a non EPA approved refrigarant into one of my clients systems I risk losing my EPA license. If someone got hurt because of it, I'd go to jail.[/quote']

 

I agree that it i a liability issue...and i completely and fully reccomend you read up on it. I personally dont have a HC system, but the ol'zcar might end up with one someday here when its put back together...

 

I wonder how the propane ignited on your friend...there needs to be a spark for a flame. Oh well doesnt to much matter, its good that your friend didnt lose his sight or somehting like that. Although had it been R-12 or R-134a he could have gotten burned or frostbite as well deeping on the status of the system and location of the hose.

 

Thanks for the friendly welcome BTW

 

silverbullet- I have no idea if shops usually have the stuff to do it. I assume most do though, although they may need to order the stuff. I personally dont work in a shop, so i couldnt tell you, but if you call around to some A/C shops im sure you'll find one that can make hoses for you. If that fails try getting a hold of a custom car shop/hot rod shop since those often has custom A/C system in them.