Electrical compartment

As I began developing my plans for my restoration (with personalizations), I was faced with the challenge of deciding where to house the electrical upgrades while making them still accessible.  Since I am building a works rally replica, I've studied these cars rather extensively.  None of them use the rear jump seats as seats.....and since, in almost any scenario, the rear jump seats would not be an accepted location to ride in today's world.... I looked there for my inspiration.  Ultimately, what I decided was to build an electronic compartment in that area.  I've build it in a fashion similar to that of the rear access panel in BN6-7's. 

 This modification, while appearing rather extensive, could be easily reversed if someone was so inclined.  The body structure has not been modified in any way and the compartment can be unbolted with 8 bolts, 4 per side.  However, the removeable jump seat pans were modified to allow storage pockets.  Putting the electronic compartment in the rear creates a challenge to find acceptable pathways for the wiring.  This could be dealt with in a number of ways.  Certainly, the simplest approach would have been to route wire for the new components under the carpet against the tunnel or inner sills.  Another approach might have been to run the wiring under the car.  What I chose to do was to make a wire channel in the passenger compartment floor that put the wiring out of harms way, protected from the elements, and relatively accessible if you want to add wires later.  This modification takes the project to another level of complexity, but since I had my car torn down to bare metal superstructure, it was all very doable.  I'll address this at the end of this project paper.  This first picture is of the completed electrical compartment, it has been powdercoated with black wrinkle finish, which will ultimately be upholstered. (Pic #1)

If you plan to duplicate this compartment, the first thing to do is to establish the exact physical dimensions.  After spending considerable time studying the back area and considering my options, I made mounting plates that would attach to the rear fender wells and bolted them into place, 2 bolts per bracket and 2 brackets per side.  Then I cut the main frame pieces out of 1/4" steel square tubing and welded them to the mounting plates. (Pic #2)  This approach ensures that the electronics compartment fits like a glove and, yet, is easy to slip in and out for the rest of the fabrication process.       

I discovered that, under load, the resulting structure flexed a bit in the center.  Since I intend to put luggage on top of the compartment, I felt it needed a touch more support.  Putting spacers under the center points gives it the loadbearing capacity I wanted.  (Pic #3)  The compartment frame structure lower skeleton is contoured to follow the Healey rear seat pan, but it doesn't go over the seat area since I plan to use that space for storage pockets. 

With the initial frame structure complete, measure the angle of the frame downturn.  Then, using a metal break, match that angle for an aluminum panel and trial fit.  Of course, the objective is to fit the panel angle as closely to the angle of the frame as possible....perfect is just about right, and, happily, that's what I ended up with. (Pic #4) 

Having finalized the lower compartment panel, I trial fit a number of components that I was planning on housing in the electronic compartment, i.e. EFI computer (ECU), radio, amplifier, fuse panel, fan controller, etc.  One of the things I needed to establish was the required height of the upper panel, which will be the door, and the storage pocket size for the ECU. (Pic #5)     

Based on the size of the ECU I am using, I built storage pockets into the lower panel.  I will only need one for the ECU, but I put them in both sides just to maximize my space as I'm sure by the time I'm finished I'll have come up with a use for the extra one.  I made cardboard mock-ups of the storage pockets to get the correct size and angles. (Pic #6)  In this picture you can see the actual size measurements of the pockets.  I then had aluminum ones fabricated to match the cardboard mock-ups. (Pic #6b)  In this picture you can also get a good view of how the bottom aluminum panel and the frame structure fit together.  The pockets will be pop riveted to the lower panel, and the lower panel will be pop riveted to the 1/4" square tubing frame.  Note that these storage pockets add considerable structural strength to the lower panel.

This picture (Pic #7) shows the top of the lower panel with the storage pockets in place.  As I've already mentioned, I sized my storage pockets to fit the fuel injection ECU, but, obviously, you could build them to meet your specific needs.  The pocket compartments will necessitate putting a relief area in the rear seat pans.....so if you don't want to cut your seat pans to fit, don't put in these storage pockets or make them smaller.  Here you can also see the beginning of the frame for the lower lip of the upper panel (the 1/4" square tubing at the bottom front of the structure).  Pic #7b shows the relief needed in the seat pans to fit the storage pockets.  At a later date I will metal finish the seat pans.


Now it gets tricky.  I wanted an opening top panel with fixed side panels.  The fixed side panels are intented to make it easier for the upholsterer to transition the fabric from the fender wells to the flat area.  I also want the top panel to angle down at less than a right angle to soften the look and to make it more like the access panels on the BN6-7's. To start the process, I worked with the fixed side panels to get an angle that was pleasing to the eye.  (Pic #8) 

With the fixed side framing complete, I did another trial fitting of the electronic compartment.  I placed in some of the larger components to validate the height of the compartment.  (Pic #9)  The fuse panel you see in this picture is not the one I ended up using.  I decided it was too bulky, and one of the newer technology, more compact, fuse panels would be a better choice.

Following the validation, I bolted the fixed side panel framing in place.  I didn't weld them since I would need to take it all apart for powder coating and final assembly.  Then I mounted the compartment's rear door frame, still using 1/4" square tubing, to hinges against the rear fixed compartment frame......then, attached the forward facing tubes.  Here you see the positioning of compartment door forward facing tubes before attaching down tubes. (Pic #10)

If you plan on having the electronic compartment upholstered, you must be careful when fitting the compartment door to provide sufficient space between the door frame and the fixed side frame for the upholstery.  There will need to be room to roll the vinyl, or whatever you will be using, around the edges.  I measured my material needs and found a 1/4" spacer would give me the clearance I needed.  (Pic #11)

Now I moved on to the final door frame fabrication which included finishing the end down tubes and making a center door frame brace.  The angle iron is used just to keep everything square as I do my final welding.  (Pic #12)

I did another trial fitting (actually probably one of hundreds) to ensure everything is fitting together as planned.  (Pic #13)  The old fuse panel is still seen in this picture.

Amazing, the hinged door is actually functioning as designed!!!.....sometimes I get lucky!  (Pic #14)

Now the final top aluminum panels are made to fit......there are 4; the large door panel, 2 side panels, and the lower front panel.  These were all pop riveted into place.  (Pic #15)  The second picuture (Pic #15b) gives a good view of the mounting brackets that attach to the wheel wells. 

This is a picture of the final fitting of the electronic compartment.  (Pic #16)  I then disassembled the whole thing and sent it to the powder coater to get a nice covering of black wrinkle finish.  While the top areas will be upholstered, the insides will not, so I wanted them finished looking when it's open, and, of course, to protect it from corrosion. 

When I got the parts back from the powder coater I reassembled it.  Before reattaching the top portion, I covered the bottom with a high quality sound and heat insulator from Second Skin Automotive Insulation (Damplifier Pro). (Pic #17)  (Link to Second Skin)  Pic #17b shows the installation of this insulation before reinstalling the electrical compartment.  I should note that I am using this insulation on the entire inside of the car, double layers on all engine facing surfaces. 


Here is what it looks like with almost all of the wiring completed.  I currently have 23 fuses (a step up from the original 2), 6 additional relays, Secret Audio radio, USB radio connector, Alpine amp, SPAL fan controller, knock sensor, and ECU.  As you can see I'm using the extra storage pocket for all the electrical documentation.  (Pic #18)

The last element of overall electrical infrastructure is the wire channel.  The wire channel provides a protected area for the wires to travel between the engine compartment, dash, and the electrical compartment.  The channel goes from the front edge of the passenger footwell to just behind the passenger seat mounting brackets.  I made the channel 3" wide and 1" deep.  This holds a lot of wires, but with all my electrical upgrades I've managed to just about fill it up.  If I add/modify electrical components, I can relatively easily add wires by opening the wire channel access panel in the passenger compartment.  (Pic #19)

This inside picture (Pic #20) shows the 1" angle iron spacers that I welded into the footwell....this places the toe board 1" off the floor to allow the wiring to pass behind it as it is routed to the wire channel.  Since the seats brackets have been repositioned to allow moving rearward an additional 2", the 1" reduction in footwell space doesn't matter.  In this picture you can also see the hole for the wiring to pass through into the engine compartment.  I've welded up most of the other firewall pass throughs to clean up the firewall and wiring into the engine compartment....and to reduce the opportunity for heat to come in through the many rubber grommets in the firewall.  


With the false toe board in place and the wire channel cover attached it makes a very tidy installation.  Access to both are easy by means of the allen head screws.  If you look carefully, you'll also note that I've welded round rod to the edges of the false toe board and wire channel cover where the wires make a turn....this prevents vibrations from fraying the wires over time.  (Pic #21)

The wire channel ends under the passenger seat at the rear outrigger.  Ending the channel at the outrigger made installation of the wire channel a bit easier and, with the abover floor channel, all the wiring is still completely protected.  In the final configuration there will be a panel that goes from the bottom of the electrical compartment to the floor.....the panel will be upholstered.  (Pic #22)  The wiring you see to the right of the picture, that is not in the wire channel, goes to the cruise control switches which are hidden in the astray on the center console (I can't take credit for that idea, it was Lin Rose's).  You may also notice that the plugs are the modern high quality weatherpack style, these were used throughout the electrical system in an attempt to expunge Lucas gremlins from the system! 


The final step was to complete the pass through to the engine compartment.  The pass through panel is in the passenger side footwell, just behind the false toe board.  It is attached with 8 allen head screws which have nuts welded to the footwell so the srews can be easily removed if there is a need to add additional wiring at a later date.  All pass throughs were carefully sealed against fumes and heat from the engine compartment.  (Pic #23, 23b)  For you curious types, the silver canister you see mounted on the fenderwell in Pic #23 is the A/C dryer.    

Now that all the functional wiring is complete, I can take it for a drive around the neighborhood.  I think it's time to start adding the body panels.

Happy motoring,

Steve Thomton

This project paper was first posted on Oct. 25, 2009.