ElectroClassic EV
Classic Cars Reborn into the Electric Future

Electric Windows

Porsche designed their manual crank style windows to be sturdy, yet fairly simple. Once I saw how it all worked, my apprehension about tackling the inner door mechanisms quickly evaporated.  So while the guts of the doors were still accessible, I took the leap and installed electric window motors.  After all, what electric car shouldn’t have electric windows?  I was surprised at the selection of universal kits, fitting a wide variety of early model cars that never even had power windows.  Most take a commonsense approach that focuses on turning the window crank itself.  They employ a splined collar that slips over the bare window crankshaft nub, turned by a cable loop that’s driven by a motor.  The motor gets mounted in an empty space inside the door, and the crank collar is so slim that it can remain forever hidden under the door panel.


After some research and reading online forums, I discovered that SPAL Automotive makes power window kits that are well-liked among custom car enthusiasts.  I purchased the deluxe kit directly from SPAL, and added the 3-switch kit so I can operate both windows from the driver’s side.


Picking an open space inside the door and mounting the motors was actually pretty easy.  SPAL provides all the brackets, spacers, adapters and other needed hardware in the kit.  My only hitch was a molded ridge in the door sheet metal that prevented the cable sleeves from laying flush with the crank collar.  My remedy was a manual coping saw and a pair of pliers to cut and bend that section of the ridge flat, so the window crank collar could lay as flush to the door as possible.


I sealed the exposed metal edges with some POR-15, and then used the provided brackets to mount the motor in the empty space under the quarter window.  This is the same spot where many 914 owners cut out a section of door brace to mount speakers, as seen in the picture above. (My speakers will go in the original position above the left and right rockers.)  I used stainless steel screws, nuts and lock-washers to prevent any possibility of rust.  Even though inside the door, these components will still be exposed to moisture.


The next step was routing the switch wiring from inside the doors to the fuse panel inside the car.  I initially thought  feeding the harness through the door stay slot might work, but there was still no path into the car. I ended up drilling holes in both the door and the jamb, choosing a spot that put the least stress on the wiring through the full swing of the door.  I sealed the exposed edges with some POR-15 and then installed rubber grommets to keep out the weather and protect the wires.  In the image above, you can see the two small holes just under the door stay between the two hinges.


I’ve received some good advice to make sure the wiring harness has room to stretch, so it was important to build some slack into the power window wiring between the door and body.  The above picture shows the black sleeved wiring loop I created between the hinges that will allow the wires to flex comfortably without stressing.

(**Click here to see the power window switch wiring.)


Added bonus: The doors got installed!  Once they were finessed into position and the hinge plates tightened firmly, the doors behaved showroom clean, closing with that satisfying “CHOONK” sound that new car doors make.  However, now the car is more difficult to roll around, since both fully assembled doors together add about 150 pounds to the overall vehicle weight.  Happy to have more space in the garage, though.


4 Responses to “Electric Windows”

  1. Wow, that’s a great idea – excellent pics. For those of us that have speakers in the door panels, do you think the motor could be mounted above where you placed the motor (under the sail window)? Are you planning to install a center console? If so and you haven’t cut holes for the window switches, you could take the Mercedes Benz approach to window switch location and mount them in the console between the seats, just in front of the defrost lever – or does the defrost lever go away with the electric conversion? If so check into the mod where you mount 25 dollar bilge fans in the area behind the speakers to increase air flow up to the dash for defrosting. Feel free to email me for details. Take care.

  2. Hey Rob – Regarding the placement of the motor, if there were a speaker mounted in the door, there would be still be some extra space between it and the sail window, but you would need to exercise some contortions to make it work. I’d probably reposition the speakers to their original factory position. 914 Appearance & Performance http://www.914ap.com/products.php makes some nice fiberglass speaker housings. I do have a center console on order, but the provided harness for the windows is setup for the switches on the doors. I like them better there anyways. I need to investigate the defrost lever. I assume you mean the red knobbed lever on the tunnel between the seats. My impression was that this opened the butterflies on the heater boxes. If I’m correct, then that goes away (or I purpose it for something else). I’m also installing an electric ceramic heater in a universal blower housing to feed heat to the fresh air box between the wipers, so I won’t be needing the bilge fans. Good idea though. Thanks for your comments.

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