Nicely done Andy! Glad this trick worked for you!
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Nicely done Andy! Glad this trick worked for you!
I didn't have any copper pipe, but was able to install the VOV using the hard plastic tube from a ball point pen I had lying around.
I am reviving this thread to get some feedback: For those of you that opted to install the variable orifice tube/ VOV, does it fit in our application the same as the original tube? Any considerations other than the second o-ring? Is it equally effective in R12 and R134a refrigerant?
Aside from installation, how do you like it? It seems like it is a simple upgrade that has some advantages, especially in a hot climate. Or is that hype?
Thanks!
Hi Dana,
I never experienced my D with R12. The system didn't work when I acquired it in 94. When I did take it to a shop for repair in the late 90's the guy said, he no longer did R-12 servicing and was just doing 134a conversions. That guy told me he installed a ford spec orifice tube, he said those seemed to perform a bit better with 134a conversions. Hard to say if it did or not, since I had nothing to compare it with. The one issue that still remained was a very slow leak. The guy told me the evaporator was likely suspect since the inlet pipe had been damaged trying to remove the Orifice tube and there was internal pit corrosion. For the next decade I Limped it along, by adding refrigerant just before any planned trips. In 2010 I finally had had enough and took the plunge into an EVAPORATOR replacement. At that time, I figured as long as I'm in there, I might go with the "VOV" figuring it won't hurt anything and if I can get 5-6 degrees cooler performance at idle, why not try it. Does it make a marked difference? I can't tell, I didnt' do a before and after test. Once the initial solar heating of the interior has been over come, I tend to switch back and forth between Fans speed 1-2 to maintain comfort levels depending on cloud cover. I have an IR/UV windshield which makes a substantial difference in heat transmission. The door windows, however, can be a solar cooker. Especially certain times of day and direction of travel.
The difference in price is between a standard replacement orifice and smart VOV is about $20.
As for installation issues, I found I could not install it with the O-rings that came with it. The O-ring cross section diameter was too big. I installed slightly smaller ID O-rings with a smaller cross section. Once in the groves, the OD's were about 1/4 (cross section) proud of the VOV body diameter. I made an installation tool out of some scrap aluminum tube at my work. Basically cutting it lengthwise with a band saw. So it would fit over the VOV inlet screen and push directly on the VOV body. The VOV installed easily with a little Pre-lubing of the O-rings with refrigerant OIL.
Hi Dana,
I'm like Dennis, It's been so long since I had working R12 that I don't remember but I do know the R12 was COLD. The R134a complete conversion I did with the VOV is PRETTY COLD. No matter what system you have, it seems like it takes a good 20 minutes to really cool down the cabin after it's been sitting in the sun all day. Once the cabin starts to cool off I can maintain a good temperature at speeds 1 and 2 no problem just like Dennis, which ultimately is what you are aiming for I think.
All that being said, I prefer my 2014 Audi when the temps in Kansas City are brutal with high humidity. Sorry DeLorean.
Andy
Thanks guys for the feedback. It sounds like $20 well spent...
So, I bought a VOV, MT0631 from Auto Zone ($22 with a discount). I just want to ensure the it is the right one, because it's seems to be smaller than the pictures....
Attachment 46291
Or is that my perception?
That's the CORRECT one for the EVAPORATOR inlet. They also make a version that's meant to be installed on some CONDENSER outlets. Be sure to wet the O-rings with compressor oil.
Dennis
Thanks Dennis. I just wanted to check. I'll be sure to oil the o-rings. I'll also make the copper pipe tool as described above.
Cheers,
This is my homemade VOV insertion tool. It's 3/8 x .035 aluminum tube.Quote:
Originally Posted by DMC-81
It slides over the Screen and pushes against the Round section of the white side.
http://uploads.tapatalk-cdn.com/2016...d92c15bc54.jpg
http://uploads.tapatalk-cdn.com/2016...b8fa9f1385.jpg
Dennis
^Dennis, you could probably make and sell those for people... I know I'd buy one.
I just took the tube and ran it through a vertical band saw. Then dressed the slot with a micro file followed by edge debuting. Although you don't see it in the photo the tube is about 6 inches long.
The orifice tube insertion and removal tools I've found online don't work like this one. They are for orifice tubes that have "ear tabs" that the tool hooks around to pull on. I wasn't able to find one that worked the way I wanted it too. So, I made my own.
Dennis
Thanks again Dennis for the tips on making the tool. :wrenchin:
I agree with Brandon that it is a great product idea.
Can anyone tell me if this is a broken orifice tube? It's 2 inches into the evaporator pipe.Attachment 68831
And how can I get it out?
Thanks
Sure looks like it to me
Get one of these: https://www.centurytool.net/Gm_Ford_...p/msc91009.htm
Or you can use a screw. Either way, make sure you run it eight down the center to avoid piercing the tube.
I used air pressure to blow mine out. If your orifice is plugged little air is needed if not you need more air flow but the hole is pretty small so still should work.
Since the thread mentions the variable orifice tubes, those that have installed one, are they noisy as some owners have stated them to be?
I have never noticed this.Quote:
Originally Posted by dmcman73
Good to know. I have a variable one and just the plain regular GM one, deciding which one to install. I've read that owners that did install a variable one could hear a very noticeable whine in the system as the pressures changed.Quote:
Originally Posted by 82DMC12
I have the black GM variable valve in and I've never noticed any "whine" while driving. I can hear it bubbling when I park in my garage and shut the car off sometimes though.Quote:
Originally Posted by dmcman73
If you are going R12, use the GM. I've never used a variable on a D...mixed stories, mostly not good....Quote:
Originally Posted by dmcman73
I'd like to learn more about this subject. My A/C is "fine" but of course not as effective as my daily driver (Audi Q5). I'm not sure if the A/C can work any better than it already does. I've converted to R134a with a new compressor (Sanden SD5H14), a parallel flow condenser, new dryer, the VOV, and replaced all the hoses front to back with the kit from Hervey a few years ago. The only part that's original is the evaporator.Quote:
Originally Posted by Ron
Is a single-orifice valve better? Also I heard there's a SD7 compressor that's "better" but how much better is not clear.
I'm going to open up my A/C next week for major frame service so now's the time for further upgrades.
One other piece of info I was told when converting to R134a, from some other owners, was to adjust the low pressure switch using the screw that is in-between the prongs of it. The right way would be to adjust it using pressure gauges (I don't remember the specifics), or, a generic way is simply turning it one full rotation counter clock wise. It supposedly helps a lot.Quote:
Originally Posted by 82DMC12
One thing I found that really improved the AC cooling is to open that condensation drain. The OEM design has that elbow crimped I guess to try to reduce air flow loss but it makes the drain plug up and the water in the evaporator box blocks air flow over the evaporator.Quote:
Originally Posted by 82DMC12
I removed the OEM drain and did the "Bill" fix to use a coil boot. I added a normal elbow to a hose running to a drain hole drilled in the floor. That also keeps the water off the frame.
My experience and research over the years: R134a has a lighter molecular size, lower heat transfer rare, requires a larger condenser, runs at higher pressures, and results with ~5°F lower output air (in a D)...~15% less efficient.Quote:
Originally Posted by 82DMC12
The only reason I know some use variable orifices, in a D, is because of R134a's higher pressures.
The Saden SD5H14 & SD7H14 have a good rep - Beware of knockoffs!
Seems your setup should be OK for KS,
(R12 would do better, but you would have to use a quality flush and a different type oil....)
Generally, a system is OK if:
70°F, 20% humidity, 35-40°F at vent...
80°F, 90% humidity, 45-50°F at vent.
The best advice is to try to stay with R-12 as long as you can. The system was designed for it and any other refrigerant is not going to have the cooling capacity of -12. If you can't get -12 the next best choice is R-414b. It is a drop-in blended replacement but should not be used in a leaky system because you can only "top off" twice, after that you mess up the blend proportions. Finally we have -134. To use it you must flush the system, change all of the hoses and "O" rings, drain the oil from the compressor and refill with the correct stuff, change the service ports and accumulator, and adjust the low pressure switch. After all of that you lose about 10% of your cooling capacity. In a place like Florida you will notice it on a really hot day.