Question for the A.C. Guys, 73 VIR

[Tder1]

Hi Guys, Restoring the R12 System in my 73. Replaced everything except I hit a snag with my Receiver. I have noticed that the Canister on the bottom of the new Receiver Valve is about 3/4" shorter than the OEM Valve I took out. Is this going to be an issue or do I need to have that xtra capacity with the longer one before I charge $400 worth of Freon.  I picked it up new rebuilt dirt cheap so I really want to use it. I suppose I could change the pickup tube inside and use the old can if I have to but I already have it mounted and holding Vacuum fine. Can I get away with the smaller capacity Receiver?

Edited April 8, 2016 by Tder1 (see edit history)

[Seafoam65]

                  The VIR systems are very trouble prone.....we used to have to replace them in my car repair shop when the cars

were almost new. Unless you have all new GM parts in your VIR system I wouldn't trust it to work properly. What we've been doing for the

last 15 years in my shop is installing a VIR    eliminator kit which converts the A/C to the 77 and newer style cycling clutch system. This

setup is completely trouble free and has the added bonus of protecting the compressor by shutting it off if the low side goes too low.

I know that you probably want to keep the setup looking stock, but the VIR is a pain in the Arse....That's why GM dropped it  after just three years of use....it looked good on paper but out in the field it was a disaster. The eliminator kit looks like the factory did it once it is installed and most people probably wouldn't even notice that you changed the setup. My 65 has a cycling clutch conversion kit on it that eliminates the troublesome  suction throttling valve. It looks like the factory did it, and it is colder than blue blazes. Even

on a very hot day, two minutes of high blower and I have to turn it down because I'm getting frostbite. 

Edited April 9, 2016 by Seafoam65 (see edit history)

[Tder1]

Thanks Winston, Advice being considered. Sounds like you've been around the block with these. There is just too much function packed into the valve package to work reliably.  My basic question. Would a valve say from a Skylark which has a smaller receiver work in a Riviera  full size system? Or does it need the extra holding capacity for the Freon ?

[Seafoam65]

              It should work fine.....the charge capacity would be a very minimal amount less....just charge it till there are no bubbles

in the sight glass on the VIR unit.  One thing you want to do before putting expensive R12 in the system is pump it down, close the

valve on your gauges  and walk away for 24 hours and make sure that it's still holding 30 inches of vacuum. If it is you have no leaks in the system.

[Tder1]

Thanks a lot for your advice. It was bugging the hell out of me so I went and changed to the longer pickup tube and longer receiver cover so I'm back to Original capacity. The Evap. is new and I didn't want to have trouble with the receiver not holding enough Freon to manage the demand. Pulled 30 yesterday and it is holding just fine as of this morning. I'll leave it sitting for another day or so  before I attempt to charge it. Let you know how it works out. I think it will be OK.

Thanks again for your input. We'll see.