Guest Erlyriv Posted August 3, 2011 Share Posted August 3, 2011 Has anyone done the suction throttling valve conversion? It makes your A/C system cycling, instead of non- cycling. Gets rid of the Diaphram and piston inside, I believe. Didn't know how big a pita it was. Thanks, Todd Link to comment Share on other sites More sharing options...
johnrex Posted August 3, 2011 Share Posted August 3, 2011 It's a fairly easy job if you follow the instructions. They are pretty good. You should replace the dryer and all o-rings before evacuating the system. I converted my 1964 about 5 years ago and have had no problems. Link to comment Share on other sites More sharing options...
Guest Erlyriv Posted August 3, 2011 Share Posted August 3, 2011 John, Saw there was a few parts in the pic for the conversion, didn't know how good the instructions were. Are all the o-rings pictured the ones you need to replace per instructions?Old Air Products - Home of the HURRICANE Heat, Cool, & Defrost A/C System - Stv Update Kit Link to comment Share on other sites More sharing options...
steelman Posted August 3, 2011 Share Posted August 3, 2011 Really easy to do. I did mine while I was reworking the entire system, but not a PITA at all. Can't really mess this up. Remove six screws, remove spring, add block off plate, replace screws. Not quite that easy, but close. Link to comment Share on other sites More sharing options...
Guest Erlyriv Posted August 3, 2011 Share Posted August 3, 2011 Ok,Looks like the block off plate is easy.Then you ned to mount switch and wiring.What is the gasket and seal for, o-rings/Are these the replacement ones for the system? thanks, Todd Link to comment Share on other sites More sharing options...
johnrex Posted August 4, 2011 Share Posted August 4, 2011 I bought a complete set of o-rings so I could replace everything I touched in the installation. Link to comment Share on other sites More sharing options...
1965rivgs Posted August 4, 2011 Share Posted August 4, 2011 Why not rebuild the original STV valve with a new piston/diaphram? I see these often on Ebay from $25-$75. I believe these are also available from the AC dealers who regularly advertise the cycling conversion kits. Some things to consider.... The A6 compressor was not designed to cycle, especially at high speeds. This original comp has much displacement and the clutch is heavily loaded when engaging and disengaging, especially at high speeds. Is your 40 + year old clutch up to the task? Also, the engine idle setting will need to be adjusted to compensate for the continuous loading and unloading a cycling compressor presents. So, when not using the AC and when the compressor is dis-engaged the engine RPM will be adjusted on the high side and when the comp is engaged it will drop. It is true this will occur with a continuous run comp when the operator manually calls for AC but, personally, I would find the cycling to be irritating, especially in stop and go traffic and even more so in a dual quad car which may already have idle quality issues. It is true the original STV valve is much more complicated than the cycling switch conversion but aside from the advantages I have mentioned the STV valve also maintains a more constant evaporator pressure which directly corresponds with more consistent outlet temps. This is a bonus when converting to 134 which will not cool as effectively. The original STV valve is also adjustable to make slight adjustments to the evap pressure; another bonus if converting to 134. This is not possible on the cycling conversion unless an adjustable temp switch is provided. Is it adjustable??? If not I would prefer to have that option if converting. The adjustable temp switches should be readily available and would really help to fine tune the conversion. If one intends to rebuild an original STV the vacuum control half of the valve is also a consideration. In this regard Riviera owners (as opposed to other full size Buicks) are in luck as the Riviera STV valve goes into full cooling mode in the absence of a vacuum. So, if the vacuum side of your STV valve is bad and a replacement vacuum diaphram cannot be obtained the end result is your STV valve will always operate in the max cooling mode. This is rarely a problem with the first gen cars as there is typically much outside air leaking into the cabin. Just some thoughts...Tom Mooney Link to comment Share on other sites More sharing options...
Guest Erlyriv Posted August 4, 2011 Share Posted August 4, 2011 I guess I thought the rebuild route was not an option, hence the conversion kit.I have no problem doing the rebuild, if the kits are available. I know that the diaphram/piston do have some issues, but I'd think they would hold up for a decent period of time.I'll have to research the rebuild kits. I know replacement diaphrams are availble.I'd rather have it operate as it was designed, for the reasons you mentioned above.If the weather stays like it has , any air would be nice. Thanks, Todd Link to comment Share on other sites More sharing options...
NTX5467 Posted August 8, 2011 Share Posted August 8, 2011 I concur, rebuilding what you have is a better option, to me. From the original adjustment of the STV, turn the adjusting screw 1/2 turn CCW to slightly lower the evap pressure from 29.5 to 26.5 and you should have cooling comparable to R12 with R134a, as to vent outlet temps in the 40 degree range. One guy in the BCA General Forum changed his '69 Skylark convertible to R134a and did not adjust the POA valve, yet still had 45 degree outlet temperatures. I found the adjustment trick on the old www.ac-kits.com website's forum. It works for POA, VIR/POA, STV, HGBypass, and Chrysler EPR valves.When GM went to the CCOT orifice tube/cycling compressor system, they still were using the A-6 compressor and cycling it. But they also had a throttle solenoid on the carb to increase the idle speed, too.In the world of the Sanden 508 compressor, there are 30 rear "backs" for that compressor, including one that used stock GM FITTINGS, so the factory GM hoses will hook up directly rather than what you normally see on those compressors. I also found a Denso version of the A-6 which is a bolt-in replacement.Just some thoughts,NTX5467 Link to comment Share on other sites More sharing options...
RivNut Posted August 8, 2011 Share Posted August 8, 2011 Here's a link to a replacement A6 compressor that might be of interest to you/anyone/everyone.S6 Automotive Replacement Airconditioning Compressor Automotive Applications Link to comment Share on other sites More sharing options...
NTX5467 Posted August 9, 2011 Share Posted August 9, 2011 Thanks for that link! The picture looks like what I found last year, but from a website for a Florida vendor. As I recall, they had it priced at about $300.00, basically the same price as another website had the Sanden 508 with the GM Back on it and the mounting brackets to make it work.Take care,NTX5467 Link to comment Share on other sites More sharing options...
steelman Posted August 9, 2011 Share Posted August 9, 2011 Here's a link to a replacement A6 compressor that might be of interest to you/anyone/everyone.S6 Automotive Replacement Airconditioning Compressor Automotive ApplicationsMaybe someone has these in stock now. I tried to buy one of these when I redid my system a while back, but couldn't actually lay my hands on one. Lots of info released to test the market before these actually went into production. If anyone decides to go this way, make sure you can actually get one first, then report back, please. Link to comment Share on other sites More sharing options...
Turbinator Posted September 24, 2018 Share Posted September 24, 2018 On 8/3/2011 at 5:31 PM, Erlyriv said: Ok, Looks like the block off plate is easy.Then you ned to mount switch and wiring.What is the gasket and seal for, o-rings/ Are these the replacement ones for the system? thanks, Todd Check and confirm your clutch on your compressor is compatible with the electronic update. The electronic update cycles the clutch off and on frequently. The clutch in my A6 is NOT designed for the update. However, with driving the car. 100 miles a month who is to care? I believe it depends on what you want. I decided to stay with the STV. My STV WAS rebuilt. There are no more new STV’s that I know about. I’m rebuilding my entire system and keeping it stock. I still do not have cold air. I have leaks to fix. RRB Link to comment Share on other sites More sharing options...
Turbinator Posted November 18, 2018 Share Posted November 18, 2018 On 8/3/2011 at 8:24 PM, johnrex said: I bought a complete set of o-rings so I could replace everything I touched in the installation. Very smart move. I’m still struggling with my AC. Finally replaced everything, but the condenser. RRB Link to comment Share on other sites More sharing options...
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