A/C Installation

  There are three major components required for air conditioning your Austin Healey, the first is the compressor mounting, the second is the choice of an aftermarket A/C unit, and the third is the condenser selection.  This may be an over simplification, but if you don't get these right the system could be problematic (read, a failure).   

I used the combination A/C & Gen. bracket from Bret Blades (Two Blades), the A/C unit from Vintage Air, and a custom condenser from Classic Auto Air.  The rest of the installation I custom fabricated.  I've seen simpler approaches than mine, and I find no fault with those, but since I was not retrofitting this system into a completed car I had the opportunity to optimize areas that would not be easily accessable in an assembled car.  My goal was to integrate the heating and air conditioning system in a manner which might have been a high-end factory approach, I wanted the interior of the car to retain a "period" look, so I tried to incorporate design cues consistent with the era.  Even if you are installing A/C in an assembled car, you may find a few nuggets in my approach.  If your car is down to the chassis, what I've done could certainly be cloned. 

I'm going to break the A/C installation description into two categories: A) under hood elements and, B) in car components. 

 A) First, let's talk about the "under hood elements."  The items you need to address are 1) mounting of the compressor, 2) compressor selection, 3) drier selection and mount, 4) condensor, 5) firewall considerations, and 6) A/C and heater hoses.

Item 1, mounting of the compressor:  This one is relatively easy to handle.  If you contact Bret Blades (Bret Blades link) and acquire one of his compressor mounts you're most, if not all, of the way there.  The bracket replaces the side plate on the right hand side (generator side) of the AH 6 cylinder engine.  In fact, it is designed for hanging both an alternator and a/c compressor.  I suppose it's possible to adapt your generator to the bracket but I wanted an alternator, so this combination worked well for me.  The compressor mounting is arguably one of the most critical elements of the conversion and, yet, with Bret's brackets it becomes one of the easiest elements.  The clearances and belt alignment issues are such that I can't even imagine trying to do this from scratch.  Bret's design has evolved, and I would strongly recommend not trying to reinvent the wheel on this part.  I did, however find a couple of improvements I wanted to make in the structure and function.  I added a gusset to the main bracket that holds the alternator and compressor in place.  Bret said he hasn't had any trouble with them, but I like things super strong if they are going to hold critical elements of the running apparatus in position....and, at the early build stage, it is a pretty trivial effort to add a gusset to the support arm, assuming you have access to a welder and a bit of 1/2" square tubing (Pic #1).  I then took the gusseted plate and support arm to a machinest to have a "fly" cut done to ensure it was still level after the welding and thereby ensuring a leak free attachment to the side of the engine (Pic #2). I also chose to make the job a bit more complex by making my own tensioner arms.  I've never had a high confidence level with friction tensioners as used on most older cars alternators and compressors...and, because of cost considerations, this is understandably the approach that Bret took with these brackets.  If you love over engineered items, as I do, the fix for the friction tensioner brackets is to make heim joint connections that will never loosen....the belts may stretch but the heim joints can be easily dialed up to compensate.  This sounds a bit easier than it is since this means designing standoffs (Pic #3) to get the needed distance to provide attachment points for the heim joints....however, this is all doable with a bit of scape steel and some ingenuity.  I designed the heim joints with attachment shafts that are threaded opposite directions on opposing ends, so the center bolt adjusts both sides in or out without disconnecting a heim joint from its attachment point.  So with the strengthened mounting plate and revised heim joint tensioners, I mounted up the alternator and compressor (Pic #4, 5).