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View Full Version : HVAC case underhood - WTH is this?



BonzoHansen
03-24-2007, 07:37 PM
I'm cleaning the HVAC firewall case for my 77Z28, getting ready to put it back on. I'm looking at this little 'wing' that jets out towards the motor. Other then the vacuum ball mounting to it (I am mvoing it), what purpose does this 'wing' serve? Maybe help support the drier tank?

https://static1.pt-content.com/images/noimg.gif (http://img175.imageshack.us/my.php?image=img0907slf7.jpg)<--view from bottom, that faces engine
https://static1.pt-content.com/images/noimg.gif (http://img175.imageshack.us/my.php?image=img0908sni3.jpg)<--inside said 'wing' - nothing

It gets in the way working on the engine. I'm thinking if I remove that, and relocate the drier tank to the front near the condensor (when I fix the AC one of these days using an R4 compressor in my 3rd gen serp setup), I'll have lots more room for spark plugs, etc.

I figure I'll cut it off then fab up some kind of block out plate.

Can anyone think of a reason not to do this?

HILROD
03-25-2007, 07:00 AM
If I remember right, the evap. lines and the vacuum ball connect to that. If you use the factory lines from the firewall, you'd want to keep that to make them secure. After it's put back together you won't save any space anyway.

BonzoHansen
03-25-2007, 03:25 PM
If I remember right, the evap. lines and the vacuum ball connect to that. If you use the factory lines from the firewall, you'd want to keep that to make them secure. After it's put back together you won't save any space anyway.You'd be surprised how that little flare is right in the way.

Good call om the lines, might be, but I'm not using factory lines, so I don't think that is a concern. The vacuum ball does, but I plan on moving it out of sight, either behind the inner fender or under the dash.

Some guys at nasty z think it might be noise baffling, like in a late model air inlet box.

HILROD
03-27-2007, 06:03 AM
Are you going to use the stock evaporator in the dash? It and the drier are what connect to that area. They needs to be supported. there should be half moon hole cuts under that protrusion, for the line to exit. If you are using the stock in car stuff I don't see how you can remove that stuff without having to reweld ends on the evaporator to change the exit area and resupporting them.

BonzoHansen
03-27-2007, 06:00 PM
I do plan on using the stock evap, not the stock drier.

https://static1.pt-content.com/images/noimg.gif (http://img175.imageshack.us/my.php?image=img0907slf7.jpg)<--I just want to cut this little wing off. I'll keep the case together, the evap should be supported fine, although I'll go dbl check.

Thanks-

MonzaRacer
04-08-2007, 08:51 AM
Be careful modifying the A/c you may wind up with a line freezing up. The drier and such are designed to be close together.
also if its an CCOT(cycling clutch orifice tube) set up make sure you have proper size drier with XH7 dessicant and I would suggest using an AAOT (automatic adjusting orifice tube). The AAOT "throttles" down the refrigerant flow to keep the evaporator from flooding.
It makes R134a work much better in older systems. One trick is that we have found is that the old addage of using 80 percent of the R12 charge isnt always true, after having found that many of the systems will still take the same poundage of refrigerant charge.
The so called "Drop ins" will cause all kinds of problems, stay away.
Also when putting R134a back in an extra elelctric fan will help the system operate more efficiently.
Good luck
Lee
PS ialso have converted old POA/STV setups over to using AAOTs also.