1-wire alternator-to-switch wiring and fuses

timson

New member
Howdy Folks,

Trying to finish up the last bits on my mild 200 rebuild and I have wiring questions. I´m upgrading my 61 Comet to electronic ignition and an alternator. I´m installing the alternator (1-wire Tuff Stuff 100 amp.) and know I need to ground it, then link it to the battery post of the starter relay with a 6ga. wire.

As I am eliminating the regulator, I would like to confirm that in order to get power to the ignition switch and light switches, I simply need to run a 10 ga. wire from the same battery post of the starter relay (also connected to battery positive), through the firewall and to the switches.

This means that I do the following:
- use original black 10ga. that runs from starter relay to regulator.
- connect it to the following wires where they meet at the regulator: the Yellow 10ga.(to ignition and light switches through firewall) and the Black-yellow 14 ga. (to horns)
- eliminate the regulator, the generator, the Black-red ground wire, the Black-white field wire, and the Yellow-black 10ga. that went to the generator A post from the regulator.

If this is right, and power goes from battery straight to the ignition and light switches, where would I be wise to add fuses?

Finally, to engage the generator idiot light, I think I run a new wire from the alternator I post (under black plastic cap) to the Yellow-black 14 ga. wire at the regulator. This wire runs through the firewall and to the idiot light.

Does that sound right? Am I forgetting anything? I let the smoke out years ago (short in dome light circuit), so I´m wanting to be extra-cautious here.

Thanks for any insight you experts can give! A full report will follow.

Cheers,
Tim
 

bubba22349

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Hi Tim here's how I have done many of these generator to alternator conversations on mutilple brands of cars and trucks with both factory stock or aftermarket alternator. I have customized the basic instructions to your car and the Tuff Stuff alternator.

1. Disconnect the battery cables

2. Remove the stock 61 Comet generator, plus it's compleate stock wiring harness intact along with its fender mounted regulator.

3. Install your new 100 Amp Tuff Stuff Alternator, make sure the pulley is in correct alignment with crankshaft Dampner pulley and water pump pulley. Stock Ford / Mercury alternator engine brackets are a little different then the Generator ones, spacers might be nessary to aJust its position.

4. Alternator should be grounded through the mounting brackets to the engine make sure your have a good ground from engine to chassis / body and also going to battery negative cable. You can run an additional ground wire from alternator case bolt tab to the engine block, use atleast a 12 gauge wire or larger.

5. Run the new 6 gauge output wire from the alternator to the positive battery post of the stater Solinoid. Yes you can add an inline fuze or fusible link between alternator and positive solenoid battery post, it's a very good idea for protection of the cars wiring.

6. Extend the generator dash light wire to run all the way up to the alternator # 1 post (left side of alternator looking at it from the rear) for alternator numbers 7127, 7139, or 7140.

7. I found out long ago after doing my first couple of swaps that the old generator light bulbs won't have the correct resistance so that the new alternator swap will start to charge at idle RPM until you revved the engine up to a higher RPM, this is with the stock Ford alternator swaps anyway. I found that the solution was to change the dash light blub when you find the right blub resistance the alternator changes at idle RPM, so you might need to find a blub that fits from a car with an alternator of semular amperage. In your case the new alternator is a GM style or hybrid of the GM so keep that in mind, also usally all the older generator equipped 1950's to 1964 cars using a dash light will usally have the same size bulb sockets so with a little time researching you should be able to find the right 12 volt Bulb.

8. The cars stock wiring from the ignistion switch will work as before, its hooked up to the posative Solenoid battery post if you want to add a fuze or fusible link to protect the cars wiring add it right next to the solenoid or under the cars dash before the ignistion and headlite switch.

9. Check that the battery is fully charged or trickle charge it until it is.

10. That's should be it and you can reconnect the battery cables and enjoy your new alternator.

11. Optional, but since your going through all this work upgrading your car you might consider doing the headlite relay mod to. This will give you brighter head lights and protect your head light switch so it lasts longer. I think your car has the Quad Head lights I put both Duel & Quad head light diagrams below are links for each wiring diagram and instructions. Best of luck (y) :nod: Edited

Duel Head Light Relay Wiring Diagram for Brighter Lights
https://skippingtheinbetween.blogspot.c ... agram.html

Video on Head Light Relay Rewiring Kit
https://m.youtube.com/watch?v=bcY2CG07wi0

Quad Head Light Relay Wiring Diagram for Brighter Lights
http://www.rowand.net/shop/tech/wiringh ... relays.htm
 

timson

New member
Thanks again, Bubba, for the top-notch advice and links! Just what I needed.

I´ve read about the headlight relay upgrade, and that is definitely on my list of things to do once the car is up and running again. After redoing the engine, the transmission, the shift and carb linkages, the head, the paint, the shift collar, the driveshaft, etc. etc, these electrical mods seem the most intimidating, so I´m taking it one step at a time. Once bitten, twice shy, i guess.

Regarding the fusing, i´ve seen some setups (on this and other forums) that use a "mega-fuse" of around 100 amps or more as part of the charging circuit. Is this what is called for in my application, between the alt. and the starter relay?

I will definitely put a fuse on the alt. wire, and another on the wire to the ignition switch. How big (or small) do they need to be to keep the smoke in?

Cheers!
Tim
 

bubba22349

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timson said:
Regarding the fusing, i´ve seen some setups (on this and other forums) that use a "mega-fuse" of around 100 amps or more as part of the charging circuit. Is this what is called for in my application, between the alt. and the starter relay?

I will definitely put a fuse on the alt. wire, and another on the wire to the ignition switch. How big (or small) do they need to be to keep the smoke in?

Cheers!
Tim

Cars and trucks built before the 1980's didn't have a fuse to protect the charging system and in most cases it wouldn't ever cause trouble wiring it direct. However with the higher outputs of these alternators it's a very good idea to protect a car from an electrical fire. To fuse the alternator output in your case, the fuse needs to be rated for 100 Amps you never want to use a bigger fuse capacity then the wire size or device you want to protect. You can use severial ways to do this by an inline fuse, a circuit breaker, or a fuse able link see below for some examples. They all work well but some are easier to change if there is a problem, until you get your electrical system dialed it it might be a good idea to have a spare or two to carry with you in case of trouble.

For the cars wire harness to the Ignistion switch most of the orginal wiring is protected with the factory fuse block. Ford started putting fuse able links on the main power wires at the starter solenoid taps in the 1970's so it would be helpful in protecting the stock wire harness. For that 12 gauge wire going through the firewall use a fuse able link, inline fuse, or circuit breaker of 25 amp rating for all the stock wiring circuits. If you plan on adding more accessories or electrical items such as stereo system with multiple amps then they can be run using seperate wires and fuses to protect them. Best of luck (y) :nod: Edited

Inline Fuse Holder
https://m.youtube.com/watch?v=6ETYwKClMRQ

100 Amp Circuit Breaker
https://m.youtube.com/watch?v=rWzlQPH4Y8Q

100 Amp Fuse Able Link
https://www.summitracing.com/parts/rnb-85623?seid=srese2&utm_source=bing&utm_medium=cpc&utm_campaign=Brands+%7C+D&utm_term=4581321357466768&utm_content=GSAPI+5ba262e200e28
 

bubba22349

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You are welcome Tim, glad that I was able to be of some help. (y) :nod:
 
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