Alternator Wiring

[Landon]

I have a 69 coronet with a 440, MSD ready to run distributor, MSD 6A, HVS2 coil, dual electric rad fans, vintage air, and 30A round back alternator with old mechanical style voltage regulator. My battery keeps losing voltage after driving a while. With a meter on the battery posts, the volts go up to 12.5 or so when I rev the engine a little, so this tells me the alternator is working.

I ordered a squareback alt with dual field terminals, and a newer "flat style" voltage regulator. I plan on running a heavy wire from BAT terminal on alternator to the battery. Do I ground the extra field wire, or do I tie it into the blue/brown wire feeding the voltage regulator? I've heard both answers. My MSD box 12v IGN wire, distributor 12v IGN wire, factory blue "run" wire, and factory brown "start" wire all connect to line side of voltage regulator. Is this correct?

I also have a violet wire going from BAT terminal on alternator to the horn relay per wiring diagram, is this needed?

 

[vance.dykes]

 

[Nacho-RT74]

I ordered a squareback alt with dual field terminals, and a newer "flat style" voltage regulator. I plan on running a heavy wire from BAT terminal on alternator to the battery. Do I ground the extra field wire, or do I tie it into the blue/brown wire feeding the voltage regulator?

if you didn't changed the wiring, will need to modify it. Electronic "flat" regulator feeds the ground throught the green wire to one of the alt fields while ign switch feed the other field with positive. This is diff than earliers where the regulator sends positive to the earlier alt field system and the other brush is grounded.

My MSD box 12v IGN wire, distributor 12v IGN wire, factory blue "run" wire, and factory brown "start" wire all connect to line side of voltage regulator. Is this correct?

I also have a violet wire going from BAT terminal on alternator to the horn relay per wiring diagram, is this needed?

Violet wire is the feed for the horns when you trigger horns from steering wheel... it needs to be there


about the MSD system, you can splice all ballast wires together and remove ballast or jump ballast with a jumper wire between terminals... or also modify the ballast removing the resistor on back and replacing it a wire into the groove. That will make to keep the stock look in front and remain the harness untouched on that ( pics of this attached )

if you were to use just the MSD Box, even remove or jump the ballast is adviced, could work with the wire originally running to + lead of coil still with ballast in line, but if you are using the RTR MSD distribuitor along with the box, will need to bypass, jump or modify the ballast to feed the dist anyway.

 

[RJRENTON]

if you didn't changed the wiring, will need to modify it. Electronic "flat" regulator feeds the ground throught the green wire to one of the alt fields while ign switch feed the other field with positive. This is diff than earliers where the regulator sends positive to the earlier alt field system and the other brush is grounded.

View attachment 980055
Your explanation is not entirely correct. The BLUE wire, shown in your diagram is a switched source, that provides, the system REFERENCE voltage to the regulator AND to supply the field voltage to one of the alternators brush connection. The GREEN wire RETURNS alternator's other field connection to the voltage regulator, where the internal transistor grounds the connection thru the case to ground, providing on/off field switching of the alternators field voltage to achieve the nominal 14.5 volt system voltage by the reference connection supplied by the blue wire. The voltage regulator's ground connection is extremely important to accurate system operation. There is USUALLY an engine ground connection to the voltage regulator's case mounting bolts to insure ground continuity for proper system operation.
BOB RENTON






Violet wire is the feed for the horns when you trigger horns from steering wheel... it needs to be there


about the MSD system, you can splice all ballast wires together and remove ballast or jump ballast with a jumper wire between terminals... or also modify the ballast removing the resistor on back and replacing it a wire into the groove. That will make to keep the stock look in front and remain the harness untouched on that ( pics of this attached )

View attachment 980056 View attachment 980057

if you were to use just the MSD Box, even remove or jump the ballast is adviced, could work with the wire originally running to + lead of coil still with ballast in line, but if you are using the RTR MSD distribuitor along with the box, will need to bypass, jump or modify the ballast to feed the dist anyway.

 

[Nacho-RT74]

I went just for the basics to let him know how wire it to make it work because he sure has missed the full sistem conversion. Sure there is allways more and deeper technical information behind that.

nobody on last 5 days had posted why it wasn't work, I just told him how to wire it to make it, colored diagram included

 

[Landon]

can I ground one of the leads on my squareback alt. and connect the other lead to the green or blue lead from the new "flat" voltage reg??

 

[Nacho-RT74]

NO... as mentioned, you need to wire it like on diagram

ground the brush on dual field alt works just if using the old mechanical regulator designed for single field alt ( stock pre 70 setups ) getting just one wire, but "flat" electronic regulator works totally diff, hence the reason why wire both fields on alt are isolated and need to be wired

 

[Landon]

NO... as mentioned, you need to wire it like on diagram

ground the brush on dual field alt works just if using the old mechanical regulator designed for single field alt ( stock pre 70 setups ) getting just one wire, but "flat" electronic regulator works totally diff, hence the reason why wire both fields on alt are isolated and need to be wired

aaaah I gotcha now! What is the difference in the "flat" regulator and the flat blue regulator that puts out 13.5 V "constant"??

 

[Nacho-RT74]

one regulates according to te car needs and the other one it gets a fixed voltage rate, designed for Race purpouse. I guess that's all. But both works on the same way and are wired the same

 

[Nacho-RT74]

I guess you meant between these

and not with this:

 

[Landon]

I guess you meant between these

View attachment 980565
View attachment 980566


and not with this:

View attachment 980567

yes i ordered the top one (black). I was wondering about the middle blue one. What is the bottom blue one?

 

[RJRENTON]

one regulates according to te car needs and the other one it gets a fixed voltage rate, designed for Race purpouse. I guess that's all. But both works on the same way and are wired the same

NO....The BLUE wire provide the electronic voltage regulator the system's reference voltage of the voltage present at the battery AND the switched source from the ignigion switch. The GREEN wire RETURNS the current psth from the alternators field.....blue wire power going in TO the alternators the GREEN wire, via the alternator regulator to GROUND, thru the internal transistors. IT HAS NOTHING TO DO WITH RACE PROPOSES AS STATED.
NACHO....you need to not to explain or exemplify sonething that is incorrect....if you do not understand the how the system operates.....just ask.
BOB RENTON

 

[Nacho-RT74]

Bob, he is asking about the blue regulator, not the wire

 

[Nacho-RT74]

yes i ordered the top one (black). I was wondering about the middle blue one. What is the bottom blue one?

same purpouse than the middle one but for single field wire on pre 70 cars with factory setup...

 

[Landon]

So I will run the BAT post on alternator to the ammeter (with a fusible link), run one spade to the green lead on the regulator, and the other spade to the blue lead on the regulator.

Will it cause issues if I have the following ALL tied into the blue wire lead on the regulator:
factory blue (run) wire
factory brown (start) wire
one of the alt. leads
MSD small red
Dist. small red

Does the regulator have to have the blue run wire, or can i bring 12v ign to it from somewhere else like the wiper motor?

 

[Nacho-RT74]

So I will run the BAT post on alternator to the ammeter (with a fusible link), run one spade to the green lead on the regulator, and the other spade to the blue lead on the regulator.

no fuse link between alt and ammeter. Fuse link goes just on batt side ( between starter relay and ammeter ). Rest, yes!

Will it cause issues if I have the following ALL tied into the blue wire lead on the regulator:
factory blue (run) wire
factory brown (start) wire
one of the alt. leads
MSD small red
Dist. small red

splice ballast wires all together and on same point, the MSD wires. The alt field lead can be spliced on same reg plug as I explain next ( and shown on diagram )

Does the regulator have to have the blue run wire, or can i bring 12v ign to it from somewhere else like the wiper motor?

regulator plug get green and blue wires. Splice existant blue and green wires on the new regulator plug, and an extra blue wire running to alt.

wiper motor blue wire is a very diff source.

 

[Landon]

no fuse link between alt and ammeter. Fuse link goes just on batt side ( between starter relay and ammeter ). Rest, yes!



splice ballast wires all together and on same point, the MSD wires. The alt field lead can be spliced on same reg plug as I explain next ( and shown on diagram )




regulator plug get green and blue wires. Splice existant blue and green wires on regulator plug, and an extra blue wire running to alt.

wiper motor blue wire is a very diff source.

so the regulator needs the blue (run) wire, it can't have 12v ignition hot from somewhere else?

 

[Nacho-RT74]

why think on a diff source if already have one ?!!!

you only need to run a new blue wire between the existant one and the alt prong. On same point, splice the new plug too

 

[Landon]

why think on a diff source if already have one ?!!!

you only need to run a new blue wire between the existant one and the alt prong. On same point, splice the new plug too

i want to know if i can bring 12v ign source to the regulator from somewhere else, will it still work properly or does it have to be THAT wire?

i want to tie blue (start) and brown (run) together, & connect to MDSred/distributor red. Then get 12v ign to the regulator from a IGN hot source on the wiper motor, and tie in my 2nd alt. wire to those...?

 

[Nacho-RT74]

I already told.