Instrument panel

The roadster came with a set of wire looms from Ron Francis: 1) a rear harness; 2) main harness, the master section into which the other sub-harnesses are plugged; 3) a front harness that powers the headlights and front signal lights; 4) a dash harness for connecting the gauges; and 5) a sending unit harness.  I’ve decided to use Classic Instruments gauges so I’ll need to (probably) substantially modify the gauge harness as the gauge harness was made to connect to Autometer gauges.  The photo below shows the draft mockup of the dash arrangement that I’m likely to use (there will be some small modifications as I proceed but it’s basically the ‘competition’ layout for the race Cobras with some additional controls. Additional photos are in the instrument panel album.

This sections covers the construction of the panel out of 0.040” Al and the wiring of the gauges and switches to the Ron Francis dash wire loom.  It also goes over the covering of the dash.  The fabrication of the glove box is described in its own section.

In the competition dash, the most important gauges are directly in front of the driver: oil T, water T and the tach.  To the right, ,, in the center of the dash, are the speedometer, fuel level, volts and oil pressure.

I plan to have a starting sequence like this:

  • Main master switch ‘on' (the switch--Cole Hersee-- is on the aluminum ‘H’ member below the dash);
  • Keyed locked switch to open the circuit;
  • Fuel pump ‘on';
  • Push button start.

To the right of the speedometer is a grouping of switches:

  • An emergency flasher;
  • A ‘rain light’ (a high intensity LED cluster that I may set to act as a flashing brake light);
  • A radiator fan thermostat override switch;
  • The windshield wiper switch;
  • Passenger and driver seat-heater switches;
  • Passenger and driver footbox blower switches.

The turn signal switch and headlight brightness light switch will be toggles to the left of the steering column.

Lights attached to the body will be connected to the harness by using Weather Pack connectors so that in the event I need to remove the body I can easily disconnect the lighting circuit from the lights.

I attached the fuse ‘box’ to the chassis using the supplied fuse box plate.  

The plate was attached using rivnuts to allow for easy removal of the  box if needed.

 It’s clear that there will not be a lot of room to work with with respect to the wire loom for the dash.  

I’m using gauges from Classic Instruments.  There are relatively expensive but I think are quite ‘classic’!  The gauge set of six gauges didn’t include an oil temperature gauge so that was purchased separately.  Additionally, the fuel gauge requires a fuel sender box that was also an additional expenditure.

I purchased an under dash ‘filler’ and stabilizer from Replicar Parts and the dash and under dash panel are connected using rivnuts and bolts.

The dash will be attached to the hood loop via the aluminum connector pieces that I made from scrap Al sheets.  The ‘L’ shaped pieces will be riveted to the hoop where the Clecko is and then the dash attached to the L piece using screws.  The screws will be visible on the face of the dash.

I cut the holes for the gauges (and glove box) using a circle cutter.  The directions warn that the cutter should not be used with a hand drill.  However, I don’t have a drill press but the Experimental Aircraft Association (EAA) has a video on using the circle cutter in a hand drill to make holes in Al panels so I thought I would give it a try.  I set my drill’s ‘clutch’ on ‘soft’ and ran the drill at about 2 rps.  

It took about 5 minutes per hole but the panel turned out well:

The panel is relatively busy but I like the look.  Other builders have less busy dashes:

See the blog entry for 12/16/19 for a description of the switches.  Below is the beginning of the dash wiring process:

The instrument panel wiring schematic is shown below.

Dash schematic

I’m modifying the electrical layout to accommodate the Classic Instruments gauges.  I’ll also have a secondary circuitry to incorporate the seat heaters, rain light, Atwood blowers and trunk light.  Overall, the Ron Francis wiring harness is a good starting point.  I’m including a second blade fuse box for some of the additional accessories.

This section will be continually updated as I work on the instrument panel.