Engine Size: 350
Refrigerant Type: r134a
Ambient Temp: 80
Country of Origin: United States
First of all the system was converted last summer to r134a. Everything was flushed and cleaned out . All the hoses removed and flushed. New Variable out orifice put in and re-man compressor. Everything was working ok till the clutch went out 400 miles from home. This in turn caused a loss of the serpentine belt etc.
We couldn't get a compressor or clutch over the weekend I was there and had to get back to work on Monday.
I was able to find a used compressor from a fairly reliable source and that allowed me to get the Vette home.
I pulled a good vac on the system recharged it and thought it was cooling pretty good. That was in October.
So now its summer and its not very well at all.
I couldn't figure out what the problem was so I took it to a local guy. He is hesitant to recommend anything for his lack of knowledge on retro systems. He evacuated the system re-filled it to spec -10% but the temp will only cool to 55 degrees with the low pressure cutout bypassed. Then if he adds an ounce more the high pressure side cuts out. He thinks there could be a blockage somewhere.
I am trying to get her fixed up for a trip on Friday to the Biltmore but cant get it into a different shop ( AC specialty )till Maybe next week.
I am leaning toward a compressor problem or maybe the orifice but am seeking advice from the knowledgable gurus that frequent this forum.
Get rid of the variable orifice-- they were a lot of trouble, and put a fixed one in. Compressor must be OK if it can make enough pressure to hit the high pressure cutout.
So what seized, the compressor or the idler pulley? Compressor can be switched off, idler cannot, and you are dead meat if the idler seizes with these new single drive belt systems. I don't trust any idler pulley bearing until I see the inside of it myself, not that I am paranoid, but was made that way with the latest piles of crap on the market.
You never mentioned whether you changed your accumulator to an R-134a compatible type, that can also be problems. With a 1993, could have contacted GM for a free upgrade to R-134a if the vehicle was still under warranty, but too late now.
I realize you are seeking and advice, but can I ask if you can give some regarding your R134a conversion?
I have a thread going in this forum, but unfortunately it keeps seeming to halt or attract no answers!.
I also have a 93 Corvette LT1 which is currently running R12 and wonder if you remember what parts you changed for the R134a conversion?. Also, if you didnÃ¢ÂÂt change the condenser how well did the A/C perform after the conversion?
Thanks if you can give any info.
Edited: Tue June 08, 2010 at 7:09 PM by LoJo
Would be nice to know the pressures. Seems like you are experiencing what many of us have mentioned that the laid back T & F condenser is just not enough to dissipate the heat load of R134a. I could be wrong but shutting down at 80 degrees ambient is not a good thing. Pressures would also tell us if there truly was a restriction!
Lojo, there is only so much we can add to a post. If you think R134a is the way to go with the standard condenser it's your call. You need lots of air flow over the condenser or you will not win the cooling game and cause other issues. Personally I don't think you can achieve the needed air flow for that condenser to work well with R134a.
Nip compressors are not known to have black death issues. Even so without seeing the failure it's hard to tell how bad it could be. I was commenting on the performance issue related to older vettes and a conversion. I am not aware of any true parallel flow condenser that is a drop in replacement for your vehicle.
The bearings went out between Roanoke and Bristol We called most of the auto parts stores along the route to nashville Thankfully the hub stayed on with the balls gone out of the bearing. It made a bunch of noise and smoke but we got where we were going. The compressor was not from a vette but anotherGM product but was labeled as R134a.
When the first original compressor went out she locked up and spit oil out of the shaft seal. Luckily i was able to turn off the Ac and limp home. Thats when I got the re-man from advance with the junk clutch.
I removed and replaced the accumulator but did not specify that it was for R134a. I guess I assumed that all new parts are designed for either refrigerant. Thats what they told me about the compressor as well. I put new O rings every where and flushed teh condensor and evap with citrus smelling air conditioner flush then compressed air to remove most all of the cleaner. I then put new oil in the system compatible with R134a splitting it up part in the condensor part in the compressor and part in the drier. I used a new Variable orifice valve as that was said to better cool at slower speeds.
I didnt see the guages so I dont know what the technician saw I'm just reporting what he put on the report. They didnt charge me cause they coulnt fix it and he said he wasnt familiar with R12-->R134a conversions. Although he did know to use 10% less than spec of R134a.
I hope this answers most all of the questions raised.
What is the problem with the condensor? I've not heard of this before. I talked with several people on the corvette forum that had done the conversion before me that have had no problems.
Edited: Tue June 08, 2010 at 10:02 PM by FScammell
I got this info from GMJUNKIE on Corvette action center.
I use a Citrus based Bio-Degradable AC flush I get at a auto supply warehouse,FJC makes a excellent Flush solvent too!I have a Flush gun made ex-specially for AC systems,but you can pour the required amount of solvent into the components and then follow with Compressed air!! You will really need to remove the condenser to flush it good,It's going to have the most trash from the compressor in it!! If you can find a Smart valve("VOV" variable orifice valve),that will be great!! There well worth the $$ even though they have went up in price a little,if not the Ford Blue will work almost as well!!
Heres a little refresher on Retro Fitting!!
Edited: Tue June 08, 2010 at 10:00 PM by FScammell
My opinion with this condenser and R134a. You will need more air flow than the vette allows for a properly working R134a system! If the climate is over 80 degrees. We can spin wheels here all day long on what this person said or that person said. The pressure readings will tell you what is going on! Post them up, if you have 26 & 235 (high idle) with R134a when it is 90 degrees out, with a "properly" charged system you are good.
It was stated the system was working OK not well the way I read it. I'm not trying to stir the pot here just making points I have seen over and over with conversions. GM made suggestions on how to convert. Undercharging a system will lead to a compressor failure as you will not have the proper amount of refrigerant to move the oil in the system So to avoid that you end up having too high of pressures! Which will cause poor cooling and an early end to your compressor just like high blood pressure. Why did the clutch go out? It's not really a normal failure unless the compressor is running hot.
Again Nip's are not known for black death. So what you have if the same year is most likely oil with some wear particles in it. Post a pic if you like it can't hurt. If you all want me to just say it's all going to be fine use R134a and it will cool like a meat freezer. Fine I said it. But don't say I told you it would work perfect for years when all that is wanting to be done is a flush, oil and a few conversion items. People want the stock look I get that. But they don't make a proper 134a condenser for this vehicle in my opinion for higher temp climates. Plus the design of the car does not allow for a lot of air flow across the condenser.
I'll step back and let you all discuss this now.
TRB --- part nuber for A better Condensor?
My compressor failed as yours did but was running at the time . This caused much smoke and consternation as I was lined up in a parade at the time with about 12 other Vettes. It slung oil and junk much like yours did.
I will try and get pressure readings and post them later.
Ok I did some more testing today. Ambient Temp 78
Static pressure 110 lo side 125 Hi side.
At Idle the lo side cycles between 20-33 and the Hi side 170-250
At Hi Idle the low side cycles 18-32 and hi 225-320
I took the small access panel off the top of Evap housing and nothing is in there . Blend door is shifting fully.
I sprayed water on the condensor while running and the hi side dropped to about 200 but it didnt get any cooler inside.
I took some videos of the guages so you can see how the cycle went.
The answer is obvious. Stick with R-12. !34 doesn't improve your situation in any way so. why go looking for complications and problems ? Your system was designed for R-12, R-12 cools better and you don't have to re-engineer anything. Just restore it to original.
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