BYPASS the AMMETER? (1969 A12)

Electrical & Ignition

  1. WM23M9

    WM23M9 FBBO Gold Member FBBO Gold Member

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    Wow! Yeah that is crazy!
    So? What do you think? Car is A12 so hopefully never use wipers much ever. But does get raced a little bit! Sounds like my Regulator.went bad, had voltage spike while racing it, thats when peoblem happened. Ammeter showed discharge, and was getting dark. Dont drive it much, and I know higher RPM takes less voltage.. Alternator may be toast? Its 3 years old.. And does need replace to be safe.
    But.we all know, when u get a new or Reman alt? It may not be good out of box. Should I go 90 amp?.And have to do all the wiring upgrade? Im not even sure Id do that right. And I went to school auto electronics! Just all newer cars tought. Its all the same I know, but from experienced MOPAR guys is best solutions
    ? KInd of lost on it now?

    Thank You for all the time and help this far!
     
  2. WM23M9

    WM23M9 FBBO Gold Member FBBO Gold Member

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    Put new V Reg, Coil, 4 pin Ballast resisor, harnesses, not much left TO replace. I'd UP the wiring. But Im need pics or a diagram. Im old now..lol

    Thanks Nacho!! :moparsmiley:
     
  3. WM23M9

    WM23M9 FBBO Gold Member FBBO Gold Member

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    Im to point where I wanna put it all back together once engine harness is here tomorrow and be done. But I dont know if I should yet! With all the Ammeter horrors!!!
     
  4. WM23M9

    WM23M9 FBBO Gold Member FBBO Gold Member

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    That is nuts! So? What to do? Engine harness gets here tomorrow. Do I wait? Try upgrade the Alt feed first?

    Kinda lost now... Probably should change out Alternator. Dont, know.. Help

    20200724_001651.jpg
     
  5. Nacho-RT74

    Nacho-RT74 FBBO Gold Member FBBO Gold Member

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    Horror is based on unknown stuff. Not just on this, but on the life!

    Don't worry about put everything back like it was from factory with all new stuff even with a 200 amps alt. Wiring upgrades can be added later too. Live the experience on the new stuff and now you know how actually the charging system works, make experiments and take your own conclusions but now with the knowledge.

    Your car will keep sucking the same, and the best alt will improve everything.
     
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    • WM23M9

      WM23M9 FBBO Gold Member FBBO Gold Member

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      Yes i beleive thats best to do. If only ECU was fried? Thats replaced. If Alt isnt keeping up? I'll have to UP it ;-)

      20200724_002008.jpg
       
    • Nacho-RT74

      Nacho-RT74 FBBO Gold Member FBBO Gold Member

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      Going step by step takes one advantage... you will know what will be gaining on every step and helps on understand what affects on every step.

      I assure you with the alt upgrade and the wiring path upgrades you'll be done AND happy, but live it by yourself.
       
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      • Nacho-RT74

        Nacho-RT74 FBBO Gold Member FBBO Gold Member

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        Race cars use to use alts with big alt pulleys which usually doesn't charge a lot iddling, but that's to preserv the alternator bearings at high speeds. Your car is not a race car, but will just race ocassionally for fun.

        Mopar used two diameters for alternators along the years. Can't recall the measurements, but using the small one for a street car also improves the iddling charge capacity. These were used most on later alternators. As mentioned the bigger deal is the low capacity at idle.

        Late alternators ( 76-77 and laters ) like the post you posted where both case halfs meets in the middle are also a bit wider. Maybe couple of milimeters. They get a wider stator, hence the reason why they are wider and get more output capacity with the wire winding gauge they used. On my car I had to trim a bit the rear spacer to keep belts aligned, and also use a longer belt to keep the alt a bit outer of the block ( rear of alt was meeting with block de the extra width ) but this can be or not a deal on some cars.

        You can use also newer alts too, Nipondenso for example. But being an A12 car, I think the correct Mopar look is a plus.

        PowerMaster, TuffStuff offer good options for a higher powered alts too. Myself I have my fav one selected on a 100 amps TuffStuff with correct 72/74 stock look ( Powermaster uses the later wider case ), which I get when I have the money. My car is AC and used to be my driver in Venezuela normally using AC. All this time I have being using a later Mopar stock unit 80 amps ( 1/4 of the tuff stuff price ). Now is on jackstands getting a full body job and hoping to get it delivered in Spain where I'm actually now to drive it ocassionally ( Gas price is too much here and a Stroked 400 is a big sucker )

        For a street car I would NEVER use an alt able to feed less than 45 amps iddling ( no matter if the car sucks 25 iddling, the alt will provide JUST what the car needs, but alt will have those extra 20 amps to feed the acc &/or batt while iddling JUST if needed ). Better on 50-55 rate as minimum specially being A/C, but definitelly never less than 45 on any car.

        But to get 45 amps iddling, you need no less than 80 amps rated alternator with small pulley
         
        Last edited: Jul 24, 2020
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        • WM23M9

          WM23M9 FBBO Gold Member FBBO Gold Member

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          Ya that sounds like the plan. Mine DOES have around a .292 Comp Cam, and is a .020 Over Bore motor (Has the "A" stamp on the Pad), so idle is really "Choppy"! Have to have RPMs at idle around 775/800 still sounds like 500.. But ammeter always danced around very close to the Center of -20 ll +20, lights always went a litle dim at night but never affected "Off Idle Performance", till the one night 7/13/2020 I met buddy with his damn 68 SS 396 Camaro, (Loves getting spanked), so you know what happens! And Im 50. These things still make us 18, probably why I keep it.
          I'll just put it togher later on, (no real hurry). FedEx brings engine harness today! So at least get it up & running!

          Man I again REALLY apreciate the wisdom! I learn something new all the time.. THANKS!!
          [Let y know IF it starts, LoL]
           
        • Nacho-RT74

          Nacho-RT74 FBBO Gold Member FBBO Gold Member

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          well... I guess a choppy iddle makes harder to get a deadly center ammeter needle, but +/- 20 amps dancing needle is a 40 amps variation. To much to my taste. Higher amperage alternator should get a more stable reading.

          I just edited my last post adding:

          But to get 45 amps iddling, you need no less than 80 amps rated alternator with small pulley
           
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          • bandit67

            bandit67 FBBO Gold Member FBBO Gold Member

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            WOW, great info thread Guys, just pulled my 73 bulkhead apart and found the melted "black wire" terminal, now understand why and how to fix. I want to add AC and electric fans ,more load, Nacho, what year and model alt can I ask for at auto parts store that will give us the highest amp alt possible that will fit our late sixties / early seventies cars...is 80 amp the max....
             
          • Nacho-RT74

            Nacho-RT74 FBBO Gold Member FBBO Gold Member

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            electric fans is allways a compromise. Maybe a 80 amps alt could be not enough ( normally rated or named as 78 amps alt actually ). But that will depend on many variables. Sure NEVER source it from battery!!! allways from alternator. But... single or dual fans ? will work just with key in RUN ? or will work even with engine off and turning of by itself like modern cars ? whats the temp range cicle you plan on keep the fan working ? Using a temp sensor switch to cicle it on/off or being manually activated ?

            Stock Mopar alternators, on $60-80 rate from part shops... mid to late 80s Mopars, normally used on turbocharged models such as Shelby Charger and similars. You can search it on line on Rockauto to confirm it. You could try that one first and if still not enough, upgrade it for more, but those are on $200 rate.
             
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            • bandit67

              bandit67 FBBO Gold Member FBBO Gold Member

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              Not sure yet on dual or single fan, temp sensor switch for sure. Sounds like your preferred 100 amp Tuffstuff would be the safest, trouble free route for most needs....thanks....would mid /late eighties alts have serpentine pulleys...would they swap/accept our old v groove pulleys...
               
            • Nacho-RT74

              Nacho-RT74 FBBO Gold Member FBBO Gold Member

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              they are with V pulleys and small diameter. This is one example

              https://www.rockauto.com/en/catalog...441324,electrical,alternator+/+generator,2412

              Tuff stuff have now 130 amps alternators on stock form. I DON'T THINK that's really necesary, but the option is there. As mentioned, electric fans is a compromise, and dual, even more. However, each one should be on 8-12 amps. They are usually wired with 16 gauge wire. Sometimes even 18 if lower load.

              Dual fans have one advantage is they are smaller to fit so SHOULD suck less amperage individually. You can make work one on a low temp range and the secondary one on a higher temp range and also activated by the AC compressor.
               
            • Nacho-RT74

              Nacho-RT74 FBBO Gold Member FBBO Gold Member

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              sorry just found the ones I posted show serpentine pulley... but I know they are available with V pulley even double groove for A/C cars. Can be changed anyway.

              later nipondenso alts are good to go too... but if you want stock look, those don't look stock!
               
              Last edited: Jul 24, 2020
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              • Nacho-RT74

                Nacho-RT74 FBBO Gold Member FBBO Gold Member

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                • 72RoadrunnerGTX

                  72RoadrunnerGTX FBBO Gold Member FBBO Gold Member

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                  A couple points of contention there Nacho, there is not a level of total stock only factory loads at splice one that would gain any advantage of being feed from both sides, especially if one source is routed through a corroded or burned up Packard terminal. Most of these types of mods include other changes that reduce the stock factory loads, i.e. headlight relays.

                  At the dealers? Tell me more about that. There were C-body recalls in the mid-seventies, adding a parallel wire run from the alternator stud directly to the fuse panel. Show me a wiring diagram that indicates the factory produced vehicles with a parallel charging circuit, not sure I’ve seen one from the factory.
                   
                • Nacho-RT74

                  Nacho-RT74 FBBO Gold Member FBBO Gold Member

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                  sure: 73B-BodyEngineCompartmentWiringDiag60 amps.jpg

                  we found this wiring existant on a couple of original and untouched rear window heater glass cars ( not the deffogger but the grill inserted on glass )...

                  there is a thread about this recently talked around.

                  in fact one of these cars shows BOTH fuse links still on car on red line wire to starter relay. Which I think is not right if you ask me.

                  will search the thread and post

                  this was a new learn to me too

                  EDITING... even this diagram shows CUT AND TAPE the underdash harness ammeter wire, the 74s we found with the rear heater glass had them hooked up to ammeter. But 74 diagram is not easy to show here. I traced the wires on diagrams and shows everything conected

                  This diagram shows a single 8 gauge wire, but spliced in two wires to run thorugh the bulkhead one and through the firewall the other
                   
                  Last edited: Jul 24, 2020
                • Nacho-RT74

                  Nacho-RT74 FBBO Gold Member FBBO Gold Member

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                  and I know about the packard conectors deal, but adding the parallel wire the stock packard conectors are relaxed. even more after a good mantenience
                   
                • Nacho-RT74

                  Nacho-RT74 FBBO Gold Member FBBO Gold Member

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                  Last edited: Jul 24, 2020
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