Your experiences with 134 AC system in 240Z

[JimmyZ]

Hi All,

I'd like to find out how well the 134 system offered by MSA cools. It is my understanding that a 134 system has to be larger to provide the same cooling that an R-12 system provides. I imagine that the MSA 134 kit uses the same sized components as the R-12. Has anyone used both?

I used to have a "factory" R-12 system in my '71 240Z and it was great. It used to blow air so cold that fog came out of the vents. Have any of you found that the newer systems run as cold/comfortable? I'm looking at getting a new system because the old one needs to be replaced.

Thanks,

Jim

[sblake01]

I have no actual experience with the MSA system but from looking at it, it appears to be a typical universal fit system set up to fit in a Z rather than a designed for R134a system like the Vintage Air system that Carl mentioned in the other thread. R134a runs a higher pressures than R12 or it's alternatives. If the system isn't specifically designed for it, i.e. smaller and more tubing in the condenser and eaporator, R134a type seals and o rings, etc., it won't work as well as the system you're replacing nor will it last as long. I'd never retrofit an R12 system to R134a either, despite what you may have heard. My pratical experience there shows that will lead to premature leaking and failure of the system. There are good alternatives to R12 that mimic the qualities of R12. Freeze12 is the one I presently use. It actually operates at lower pressures than R12 which is always a good thing and it cools better IMO. There are a couple of other good R12 alternatives on the market but I'd steer clear of the ones that are hydrocarbon based. When you say your old system needs to be replaced, what problems are you having with it? Is it based on the old upright York compressor?

[MikeW]

Stephen obviously has far more experience in A/C systems than I do so you should certainly listen to his advice. Strangely enough the factory R12 compressor in my daily driver 240SX failed after about 6 years. I had my regular mechanic replace it with an R134a system at that time and it's been blowing 40 degree F air for the last 11 years.

One thing to consider with A/C in a 240Z is the effect of the blower and duct work. It really doesn't move much air. You'd probably do well with the Honda blower motor upgrade in addition to a new A/C system.

[bobc]

I've got a 134 system in my Vintage car and it works fine. All the parts were designed for 134, so it's not a retrofit of 134 parts in an original r12 system. I think MSA's system is the same thing, but I'm not sure on that one. Ask Sal at MSA.

Bob

[Inf]

I've had the MSA kit since this last winter, and it's finally starting to get hot again down here in Texas, so I'll have a better idea how well it works by the end of summer. Right now I only need to turn the thermostat a little bit to cool things down just fine. Also, in addition to the kit, I have 2 large electric fans (coming on with the a/c compressor clutch) in front of the condenser to put some more air through when the a/c is running. The local Z mechanic thought this would help out in stop and go traffic; I hope he is right - it gets up to 100F+ here in the summer regularly.

One thing I noticed is the fin density in the evaporator box is really high, and I had some problems early on with condensation. I guess with the fins so close together, the condensation didn't effectively drain out all the way and I think I had some funky stuff growing in there. It resulted in a foul smell for the first few minutes of operation every time I fired the blower up.

I sprayed some lysol into the evaporator a while back and it seemed to take care of the moldy smell, replacing it with the still not so nice odor of lysol for the next few weeks. Currently, I switch the a/c off and turn the blower on full blast a mile or so before I get home. My reasoning is to try and dry out the evaporator box a little bit before I shut everything off, since the car doesn't have the post-shutdown blower circuit that modern cars have to resolve this issue.

I can take some pictures of the install later.

I've never driven a Z with the york piston compressor, so I can't comment on the comparative load it puts on the engine. However, it is pretty noticeable when the compressor clutch locks in. Aside from the audible click from the thermostat box on the side of the console, I can feel the engine vibration coming through the shifter and pedal change, and most of the time I notice a drop in power and need to give it more gas to keep the car up to speed. I've never noticed this in the modern cars I've had.

I also almost had the A/C stall the engine out on one occasion at a stop sign, but I think that is more a factor of my leaky throttle-shaft carbs being out of whack than the a/c system overloading the engine at idle.

[Walter Moore]

I suspect that people's experience with using R134 in an old R12 system depends upon their location. I ripped the air conditioner out of my 71 because I don't want the weight or power loss, so I don't know how R134 would have worked in that system. (badly I suspect.)

On the other hand, I have owned two other cars where I "converted" the air conditioner to R134 with no problems. But then here "hot" is 85 F, and unbearable is 95 F. We only see temperatures like that for about three months out of the year typically, and usually when the air conditioner in one of my daily drivers breaks I don't bother to fix it. I am sure that southern Florida or California have different requirements.

[sblake01]

......I had my regular mechanic replace it with an R134a system at that time and it's been blowing 40 degree F air for the last 11 years........

40 degrees at the center vent? Not cold enough.

[MikeW]

40 degrees at the center vent? Not cold enough.

Yes, but while driving in hot weather. I'm impressed with your 25 degrees. What was the outside temperature that day?

[JimmyZ]

When you say your old system needs to be replaced, what problems are you having with it? Is it based on the old upright York compressor?

Thanks for the replies all.

All I have left of my old system is the interior components. The York Compressor took a dump a long time ago so I junked everything except the evaporator box. Although it could be married to new parts I'd rather get a fresh start with all new parts.

I liked the York and the R-12 kicked butt. Power loss was very minimal.

The ONLY thing leaning me towards 134 is the fact that it is easy to get which would allow me to service it myself. (With proper equip) I've heard stories about techs saying they were using R-12 and using some other crap instead. Don't know that much about A/C but I do know that mixing things can be detrimental.

Took note of Inf's post regarding mold. Could that be a drainage problem or did a lizard/etc start decaying in there?

[sblake01]

Yes, but while driving in hot weather. I'm impressed with your 25 degrees. What was the outside temperature that day?

About 90. It doesn't stay at the temp for long because that's about where the compressor will turn off until the evap. temp gets back to above freezing. It will stay basically in the low 30s at the center vent while driving even in temps over 100 degrees at the second lowest fan speed. I was testing on that day for the vent temp I could achieve at idle on the highest fan speed. The 810 which has factory air is a degree or so lower than the Z which has dealer installed air but it's the ARA system with a center mounted evaporator. Those readings were taken about a year ago using Johnson's Freeze12 which is an R-12 replacement. It's non-flamable, non-hydrocarbon, non CFC, EPA accepted, and it works with existing R-12 lubricant. I know that sounds like a commercial but I'm not trying to endorse anything here. I've experimented with a lot of refrigerants over the years and this is the one I use now because it works, hasn't caused any problems in either vehicle in a year and a half of use and costs 1/4 of what R12 costs. It runs at lower pressures that R12, takes less, and cools better. At least, that's been my experience so far.

[sblake01]

.......I liked the York and the R-12 kicked butt. Power loss was very minimal......

If you liked the York and R12, you'd love the Sanden SD508 and Freeze12.

[webdawg1]

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webdawg1