Distributor, Ignition Coil, and Ignition Switch wiring

[AndyMenon]

Best practice to have only one wire per terminator (i.e. crimp lug, spade terminal etc.) so you can isolate individual circuits in the future. Distribution block doesn't have to be right there at the switch, can be somewhere else handy. Keep in mind if you run everything from the ACC terminal (which is a good idea, as Potvinguy says), you could well exceed the current rating of the switch, in which case a relay (which you already know about) is indicated.

BTW most ignition coils generate a bit of heat and its a good idea to mount them somewhere well ventilated, or even out in the breeze. As a general rule, keeping the High Tension (high voltage) leads as short as possible is also a good rule, especially the HT from the coil to the distributor. You might consider re locating the ignition coil, which will free up space for the ACC relay and terminal block thereof. JM2CW

Thanks WM. My ignition coil is not the conventional round coil. Rather it's a bevelled shape.
This is how my wires are laid out:

1. My intention of putting the coil under the dash was to reduce the length of the wire leading to the coil positive from the fuse block. (Besides, mounting a coil of this shape on the firewall competely ruins the look of the tub).
2. Also, the panel under the dash has been filled with relays is because I wanted them as close as possible to the appliances they are used on (in my case the HI/LO Beams, the Electric Fan, Electric Water pump, Oogah Horn).
3. The relay for the fuel pump is mounted under the seat so that it can be as close to the pump mounted in the middle and below the gas tank.
4. Most positive wires run from the fuse block, down the right side edge of the tub, on the inside to the battery to minimize the length and keep them away from the fuel line, (and also, makes it easier to deal with the wires if I have to lift the body because all i got to do is detach them from the battery positive without having to pull them into the body if they were running on the frame rail).
5. Almost all ground wires for the appliances run on the driver side frame rail, to an absolute grounding point on the driver's side kickup and do not have to be touched, should the body need to be lifted from the frame. Did not want any guesswork as far as ground wires go.

Let me know if this reasoning makes sense. Will try to post some pics of the build sometime in the next few days.

Andy

 

[Wild Mango]

Hi Andy, this is given IMHO rather than as advice, keep in mind. A lot of rodding fun is doing things your way with attention to the basics.

1/ Keeping 12V wiring as short as possible is good practice, but if your wiring is sized so as to keep volt drop realistic, not imperative. I would mount the coil in a ventilated space at least, even if it meant a little extra length on the HT lead. I wouldn't want it in an enclosed space with any other wiring or devices, for instance.
2/ Yep, (see 1/) Keep in mind the relay coil current is small and therefore the volt drop in the wiring associated similarly small, so you can stash the relay wherever. For instance Rooster has a neat way to wire the electric fan which has the relay actually at the fan. I see you have done similar with the fuel pump.
3/ See 2/. It simplifies things if you keep your control wiring (switched wires to loads) identifiable from your feed wiring (power supplies to relays and switches) so as to avoid head scratching later.
4/ Make sure everything you have running from the battery (save the starter motor, and you can get circuit breakers for that too, if you want) is fused. This is absolutely vital. The battery is capable of delivering a lot of energy into a low resistance like a short circuit fault. At best this will burn out wiring in jig time, at worst it will cause a fire and people may be burnt, your rod go up in smoke. All bad.
5/ Connect your battery negative to the frame close to the battery. Clean bright metal to metal connection, no paint. That way any point on the frame is a ground. Don't forget to connect the engine block to the frame with the same size ground cable.

Keep in mind there are two basic ways to switch a load. You can switch the power supply to the load so the control power goes through the load to ground. This uses a little more wiring but is the simplest for our buckets. Another way which has become common in the auto industry is to do the switching at the ground point, this saves wire but means the whole circuit is always live to the ground point. I would avoid doing this.