Rather than specific wires , here is an understanding how it works :
old one you put + 12 v ign directly into regulator , points vibrate to vary the OUT + volts to the field ( + F ) terminal at alternator, it is at whoever value it needs such that ignition wire feeding the old regulator ( and whole car) is held at 13.8 or so . Other end of the old alternator field is grounded inside old alternator . So one wire with varying +V on it .
New one , all they had then to go solid state was NPN power transistor , the emitter has to be grounded (-) as base voltage has to be higher + than emitter to turn it on . If wired like old one 12 v through regulator you would need 15 v , ( 14 * .7 “on “ voltage ) to fully do that at 14 V out You don’t have it .
So what they Did is put constant 12 v into field all the time ( blue wire to ign * and to one F terminal ) then control the ground end ( green) of field by going through transistor to ground inside silver regulator so two brushes two F . Called “low side switch”
No way to use old alternator with that regulator design . ( aftermarket junk tries to , don’t go there)
Other blue wire at a mopar silver regulator goes to 12 ignition blue too , that powers the regulator and tells it what the ign voits are .
Guy did the right thing big step up —much better setup .
The mopar electronic ignition in instructions says not compatible with old setup ( without special 1 wire retrofit regulator ) as vibrating points can cause interference to spark pickup and volt surges (?moderately swinging ammeter is normal as regulator points open and close , flickering headlights too ( ok) although points will burn a bit , that is indication of end of life , swings get large . Maybe 50 k miles . you can file or clean ( must remove bumps) to get it ok — Don’t adjust or lose factory setting of lock screw .
So ,on your guy , Carl, — he did a good job , leave that part alone ?
What difference does shape of alternator really make in our world? New regulator far better won’t die or go crazy , steady ammeter , better alternator output too , especially at idle .
But if keeping the old , keep mechanical regulator too , use one wire from F to regulator , hot side of old regulator goes to ign hot at ballast ( Don’t get wrong end of ballast that goes to coil ) .regularity HAS to be right way around or you instantly blow it up. Grounding field on one wire ( “ to test”) by guy who does not know what he is doing instantly blows it up too .
Standard auto parts still selling good mechanical one at Rockauto , black cover etc i bought 4-5 of them before gone , good price too.
From above , note you can easily use new 2 wire alternator with one wire regulator just ground the other brush F . Makes it a one wire .
PS as you know , you absolutely need vacuum advance , otherwise 6 mpg , and has to be right vacuum advance can for ram motor — . the old J distributor will work BETTER in terms of spark ( no 1 volt solid state internal drop happens with points ) and it has the right fairly critical advance curve for J .
Of course , for a 300 lover , checking points is a huge job on a B block every 15 k miles or so ( laugh) .
Use dwell meter off ebay , less than 2 minutes ,don’t even lift cap! vs two days trying to figure out intermittent electronic junk ,,wiring and added failure modes . And I am an EE
Why Grandma likes the orange box.. or pertronix , great in a Slant six .
Adds reliability , loses performance somewhat in terms of output over dual
points .
We went 140 mph on dual
points , Granatelli 190 .
john
Sent from my iPhone
On Nov 6, 2023, at 6:25 PM, Carl <cbilter@xxxxxxxxx> wrote:
John and John,
I bought a G last summer and looking at the car tonight I see that the prior owner has installed a new, updated wiring harness and a square back 1970’s style 2 field alternator, along with a 1970’s style Mopar electronic voltage regulator mounted on the core support (along with a Mopar electronic ignition module), original regulator is gone! John Begian is getting me the correct ’61 wide fin alternator, which would be a single field. John G or John B – how can I connect the single field ’61 alternator into this wring harness? Do I just connect the green field wire but leave the other field wire disconnected??? But will that work with the 1970’s style electronic regulator??
The prior owner is a nice fella but he was trying to “upgrade” this G to more modern components. The original distributor is gone and in its place is a 1980’s vintage Mopar Performance mechanical tach drive electronic distributor (no vacuum advance) with the external Mopar ignition box mounted on the core support. I’m OK with electronic ignition – I have it on all my cars. I just don’t know how to connect the correct ’61 alternator with the Mopar electronic regulator and a two field wire harness.
Carl
