Do you need a dual field alt for the later regulator?

[vintagetin]

The title says it:
Do you need a dual field alternator for the later model regulator with the two prong triangular plug.

Some say yes, others say no.

Let me state this little fact: Looking the parts up on the Advance Auto Parts electronic catalog I found that in 1970 the single field alternators were found on cars with this regulator. So I would think it would be just fine.

The reason I'm asking it because my car always has, and is suffering from the old Dodge epidemic known as, dimming lights, and radio cutting out during bass at idle (it's just a cd player, and some 6x9's).

I have the old school regulator with the two plugs on opposite sides of an old box looking thing with breaker points in it. I'm hoping to wire the later model regulator up to the field and ignition wire to fix it.

 

[vintagetin]

Aw..No body has any input?

 

[MoparBill]

I have done the swap a few times and have used the newer alternator with 2 field terminals, running the extra field terminal to the newer regulator. I keep my eyes peeled at the boneyards for the triangle plug and grab them for my stash when I can. Lately I buy the engine harness all ready to go with electronic ignition, newer alternator and regulator. Year one sells them fairly reasonable.

 

[vintagetin]

Cool, yeah. Most auto parts stores sell the triangular pig tail for the regulator for about $6 repro.

 

[furyus]

I did this conversion with the electronic reg and dual field alt. Worked out great. When my car had the same symptoms, it turns out the alt diode went bad,so you may want to have it checked.

 

[1971RR]

This is kinda what I am dealing with now. I just replaced my alternator Saturday. The old one, as well as the new one, have the terminals marked BAT, FLD, FLD. With the alternator installed in the car, the Blue wire from the harness is connected to the top FLD and the green wire is connected to the FLD terminal at the 3 o'clock position. I get a flicker when I let off the accelerator. Did I put the terminals on reversed? Will it function with the terminals reversed? Is my regulator dying? I found a ground on the driver side firewall with just the ends clipped and screwed to the fender. One wire disappears into the harness, the other goes to the starter relay. I unscrewed it, sandpapered the spot to shiny metal and crimped the two wires together with a loop terminal and screwed it back in. Havent tried it yet to see if this might've fixed it though.

 

[Slantsixdan]

It does not matter which FLD terminal gets which field wire. Flickery line voltage is often cured by running a ground loop from the alternator housing to the regulator base and from the regulator base to the battery negative terminal.

 

[1971RR]

Thanks Dan! I'll give that shot.

 

[1971RR]

I may get around to this today. So you recommend loosening one of the small housing bolts on the alternator, running it to one of the bolts securing the regulator to the firewall (grounding on the regulator body) and from there to the ground on the battery?

 

[Slantsixdan]

That'll work, or what I more often do is find the empty round "GRD" hole on the back of the alternator and use a short self-tapping screw to secure the ground wire there. Not all alternators have a "GRD" hole, however.

 

[1971RR]

The lights still fluctuate. Probably time for a new regulator. Thanks for the assist Dan.

 

[Slantsixdan]

It's grown difficult to get a good quality regulator. Much/most/(all?) of what's available at parts stores is Chinese garbage, even from (once-)reputable brands. Old Car Parts Northwest has a ton of NOS genuine American-made Chrysler ones (and NOS Chrysler alternators, too).

Also don't forget the weak points in the wiring! Clean all the bulkhead connectors and clean/tighten all other connections throughout the system -- and don't overlook the likelihood of high resistance across the ammeter and ignition switch.

 

[1971RR]

Yeah I'm kinda on that mission right now. When I find a ground wire, I've been pulling them off, bring some shiny metal to the surface and cleaning/replacing the connectors. I pulled the main ground from my battery to my intake manifold last night. Lets just say its time for a new cable. The car did sit for 19 years. Do you have a quick and dirty test for checking the ammeter (dash gauge?) and ignition switch?

 

[Slantsixdan]

With the engine running, put a voltmeter across alternator B+ and alternator housing, then put the voltmeter across battery (+) and (-); substantial difference means high resistance in the main circuit (including the ammeter). Then put the voltmeter across the input(!) terminal of the ballast resistor and battery (-). Substantial difference between this and either of the other two measurements points to high resistance in the ignition switch and its wiring.

 

[1971RR]

I'm not running the ballast resister right now. I have a Mallory Unilite and, according to their instructions (on paper and over the phone), if I am running a coil with a resistance of 1.4ohm or greater I can take the ballast out of the circuit. I currently have a jumper wire (30amp fusable link) taking the place of the ballast.

 

[Slantsixdan]

Okeh, then read "jumper wire" for "fusible link" and test as recommended.

 

[1971RR]

14.46v at the alternator. 13.96v at the battery at idle..new ground cable from battery to intake.

 

[Slantsixdan]

Good…now what do you read when you put the voltmeter across ignition hot (at the input side of your ballast jumper) and battery negative?

 

[1971RR]

I get about 13.25v running. About 13v on the coil+ to battery-. I thought the cool was supposed to be about 8.5v. Must be lack of resister in line.

 

[Slantsixdan]

Your numbers look reasonably good. And yes, without a ballast resistor you won't have lowered voltage to the coil.