Re: New Complete Wire Harness

Posted by Gary49eight On 2021/11/16 7:09:13

Hello again everyone. Apologies for the physics lecture. Resistance depends on 3 things, resistivity of the material (hence the popularity of copper), length, and inversely proportional to area. I rebuilt my 288, so it is new and tight, starter motor rebuilt too, it would not crank on a single 6V battery using jumper leads. (It would using 12V). This is due to the length of the leads (9 feet) and the contact resistance of the alligator clips. I got some 1/2 inch cable, and eye terminals which I soldered on, with the battery in its proper place the lead to the starter and earth to the block were about 2 feet long. It cranks and starts fine.
The wire from the starter button (my car is not throttle start) to the starter solenoid does not have to be thick, it only activates the solenoid, it does not carry starting current.
Electrical power is volts x amps. Compared to a 12V system for the same power you will have twice the current. Resistance generates heat, more current means more heat for the same wire. diameter. So any high current device (to the amp gauge, the headlights, ciggy lighter) you can go up in wire size. Everything else can be normal diameter. Howard's suggestion of a headlight relay is a good idea, because the headlight switch to the relay only needs low current.
Here is another suggestion. The factory ran the wiring inside the A pillar, over the doors and down through the C pillar. It is impossible to pull through a new section of wire. I had to replace what was left of my roof lining anyway, so I replaced the wiring using 5 core trailer wire. The back of the car is the same as a trailer anyway, except for the fuel sender unit wire. Now if you have to do this, but don't want to disturb your roof lining, go to the local trailer place and you should be able to get 5 or 7 core wire, and they should have flat section. (The wires side by side, not in a round bundle.) You can then run this under the carpet, and it will not be noticeable.
Gary