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Garage / Re: It's not easy being green - 1971 TC
« Last post by RonPNW on Today at 10:33:31 AM »Having just finished re-wiring, I have few comments.
If you want a historically correct restoration ignore the rest of this post and just repair what you have.
I wanted to take advantage of modern technology in any way that did not change the character and general look of the car.
On my 70 S2 some wire was internally damaged and over 50% of the connections were corroded or failed. I removed the amp meter (not really necessary if you sort out the electrical system, I replaced it with an air / fuel meter and added an idiot light). Also remove the high current coil wire that runs through the tach (there are several posts, on this site, on how to do this. It dramatically reduces the electrical noise in the car allowing a radio to work properly).
I sized my wire by using the length and resistance of the wire (many tables on line) to find the wire gauge that results in .5V of voltage drop at max current. Voltage drop = Max Current X Total Resistance. Total resistance includes the wire to the battery, wire to ground, and any switches or connections on the way. A good clean flat connector or switch will be less than .05 ohms. Good solder connections are 0 ohms.
If you remove the ammeter the only high current connections / lines go to the radiator fan, cabin fan, headlights and starter. I added relays to front area so the cabin switches just turn on the relays.
I replaced the alternator with a mini-denso 70A ( https://www.ebay.com/itm/151571437369. ) .Smaller, lighter, more current, internally regulated. Some fab for the mounting is needed. Link to dimensions https://www.amazon.com/DENSO-EXCITING-ALTERNATOR-MOUNT-1-WIRE/dp/B00DMS4YIG.
But ..... I have heard you can simply buy a new wiring harness and move on.
Ron
If you want a historically correct restoration ignore the rest of this post and just repair what you have.
I wanted to take advantage of modern technology in any way that did not change the character and general look of the car.
On my 70 S2 some wire was internally damaged and over 50% of the connections were corroded or failed. I removed the amp meter (not really necessary if you sort out the electrical system, I replaced it with an air / fuel meter and added an idiot light). Also remove the high current coil wire that runs through the tach (there are several posts, on this site, on how to do this. It dramatically reduces the electrical noise in the car allowing a radio to work properly).
I sized my wire by using the length and resistance of the wire (many tables on line) to find the wire gauge that results in .5V of voltage drop at max current. Voltage drop = Max Current X Total Resistance. Total resistance includes the wire to the battery, wire to ground, and any switches or connections on the way. A good clean flat connector or switch will be less than .05 ohms. Good solder connections are 0 ohms.
If you remove the ammeter the only high current connections / lines go to the radiator fan, cabin fan, headlights and starter. I added relays to front area so the cabin switches just turn on the relays.
I replaced the alternator with a mini-denso 70A ( https://www.ebay.com/itm/151571437369. ) .Smaller, lighter, more current, internally regulated. Some fab for the mounting is needed. Link to dimensions https://www.amazon.com/DENSO-EXCITING-ALTERNATOR-MOUNT-1-WIRE/dp/B00DMS4YIG.
But ..... I have heard you can simply buy a new wiring harness and move on.
Ron