I regularly see the featured car for this post (a beautiful 1956 Lincoln Premiere with factory A/C) at car shows that I exhibit my Mark III at. I’ve long been fascinated by Lincolns and early automotive air conditioning, so here is my chance to combine both in a single post!
Lincoln was among the first companies to offer post-war factory air conditioning, starting in 1953. I’m still on the lookout for one to write-up for this series, having never seen a 1953 model so equipped. However, the trunk mounted system (with ceiling mounted diffusers) in the featured 1956 model is similar enough to the setup employed in earlier models, save for a few key differences.
The 1953 to 1955 systems did not employ an electromagnetic clutch. This makes sense, as the electrical systems on these cars were only 6-volt. This also meant that the pressure of the refrigerant could not be regulated by cycling the compressor. Instead, a return valve (the “Modulator Valve” above) was fitted to the condenser allowing excess high pressure vapor to recirculate to the compressor, preventing the low side pressure from dropping too low.
The modulator valve had a variable orifice, which was connected to the interior temperature control panel. This (along with a two-speed blower), afforded the driver some (albeit limited) ability to regulate the interior temperature (recall that the trunk mounted evaporator had no heater core or blend door to mix in warmer air).
The lack of an electromagnetic clutch meant that, Similar to the 1930’s Bishop and Babcock air conditioning system, the compressor on the 1953-55 systems was always engaged, whether the system was actually “running” or not. The service manual therefore recommended removing the two bolts that engaged the pulley to the compressor in the off-season, allowing the pulley to free-wheel (shown above).
For 1956, several improvements were made to the Lincoln system. For starters, all the components were upgraded to 12 volts, which allowed the incorporation of an electromagnetic clutch on the compressor. However, the clutch on the 1956 system only allowed disengaging the compressor when the system was off. The compressor still ran continuously when the system was on, and therefore still relied on the modulator valve for temperature and pressure control.
The dehydrator, which was a separate component in 1955 (as shown in previous diagram), was incorporated into the receiver in 1956, as on most modern systems.
Enough tech talk. What’s the system actually look like?
Not being a fully integrated system, the air conditioning had separate controls from the heater and defroster, as shown in the picture above. The control panel for the A/C was still an “add-on,” as clearly seen in the picture above. At least this control panel was color matched, unlike the control panel of the air-conditioned Corvair I featured earlier.
The transparent ducts going from the trunk-mounted evaporator to the headliner are clearly visible in this shot, as well as the fresh air intake for the system on the rear fender.
Ceiling mounted registers distributed cooled air to each seating position. When asked, the owner said that it cooled the interior just fine. I’m guessing that most manufacturers switched to panel mounted vents for simplicity and cost reasons, and not for any lack of effectiveness of the roof mounted vents.
The only vehicles I’ve ever ridden in with ceiling mounted vents have been modern minivans and SUVs. The experience is quite a bit different then traditional panel vents, but it seemed to work just as well.
Here’s a view of the trunk mounted evaporator. Unfortunately, most of the innards are encased, save for a small sight glass near the bottom, so you can’t really get a good look at them. In case you don’t enlarge the picture above, the plate calls for a whopping 6.5 lb. of Freon (compared to the 1.5 to 3.5 that most modern systems take). Obviously it takes a lot of refrigerant to fill to fill those long lines going back and forth from the engine to the trunk.
Up until 1956, Lincoln and Mercury shared the same trunk-mounted air conditioning system. Mercury would switch to the Ford cowl mounted setup for 1957, while Lincoln would soldier on with the trunk mounted system for one more year in 1957, before coming out with their crazy dual-core setup in 1958.