Dashboard and air intake

 I wasn't able to get in the garage today, but that didn't stop me thinking about a few tasks. First is the air intake, or 'how to get a round peg in a square hole'. In this case, the round peg is the air filter, and the square hole is the airflow meter. I was going to 3d print something, but to be honest I think I'm just going to use some 1mm plate and a circular strip, weld them together and call it a day. Much less messing about, and hopefully won't go wibbly wobbly in the engine bay.

But on to the bigger thought of the day, the dashboard;

Gauges first. I've got a speedo and a rev counter from the MX5, they need to be rehoused. Rev counter gets a digital signal from the ignitor (on a yellow blue wire). It also gets a ground and 12 volts off the meter fuse for lighting. The speedo is one less wire, with a ground and 12 volts for lighting but the drive itself is mechanical. I guess I ought to keep the temperature gauge (black blue off the temp sensor and ground/12v) and maybe the oil pressure gauge (yellow red off the pressure sensor and ground/12v). That's five wires total. 

Now lights. I would need an alternator light (white black), a brake warning light (blue yellow), left indicator (green black), right indicator (green white). I believe I also need hi beam light (red white) and fog light (red and red black). The fog light indicator is usually with the switch so I need to figure out how to rewire it to a separate bulb. That's 6 maybe 7 wires.

Lastly, switches. On the steering wheel I've got indicators and lights on a stalk, so I can leave those. There's also a horn switch on the dash that I can just reattach. The fog light switch needs to be restored (green yellow, red black). I need a hazard light switch (orange to hazard flasher). That seems to be it, just two extra switches. 

That seems a bit too easy to be honest. 4 gauges, 6 lights, 2 switches. Hmm... although that would probably explain why I've been able to remove half of the loom! 

(Later that week)

I need to take some measurements of the gauges, mainly to see how to mount them and sort out things like bezels, front glass etc. They are mounted in a shell on the MX5, so I'm going to similarly mount them on a back board first, then bring them into the dash from behind. Then some sort of bezel/surround per gauge with some glass/plastic in the middle. The back board will also serve as a mounting point for the gauge illumination bulbs. 

Anyhow, measurements;

• Rev counter. 96mm diameter on the face. 29mm from the back to the gauge face. 40mm from the back to the front of the needle (might need a bit more for clearance). 
• Speedo. 96mm diameter on the face. 40mm from electrical connectors to the gauge face. 49mm from the back to the front of the needle (again, maybe more for clearance).
• Temperature. 47mm diameter on the face. 29mm from the connectors to the gauge face. 40mm if I include the stand off (end of stand off to face). 38 from connectors to the front of the needle.
• Oil pressure is the same as temperature. 

Kind of expected really, the speedo needs more clearance as it's got a mechanism sat behind it. Should be easy to compensate with the stand offs for the other three though. The speedo also has a bigger mechanical fixing, I assume to deal with the potential twisting forces. So again it makes sense to build the base to the speedo height and get the other three to match. In theory I could mount them all separately, but then I'm making the wiring stage harder. 

I'm still stuck on material, it needs to be rigid but non-conductive, and also not brittle. I'm thinking a plastic rather than a wood? I think a visit to Wickes and Ikea is on the cards.