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Technical Generator to alternator conversion

Discussion in 'The Hokey Ass Message Board' started by oldiron 440, Nov 23, 2022.

  1. oldiron 440
    Joined: Dec 12, 2018
    Posts: 3,050

    oldiron 440
    Member

    Ok I figured this is the place to ask because of often it's probably been done here. My 64 Fairlane has had a generator and I would like to install a alternator, I will be using a output fuel pump, msd ignition and probably a decent stereo.
    I do have a one wire alternator which is a GM back on a Ford front new that I bought years ago and it's 150 amp. I've heard that this isn't good for the battery and a Ford 3G would be better. I'm not sure what you do with the wiring at the voltage regulator if not in use.
    Any ideas on wiring or witch way to go would be great.
    Thanks in advance.
     
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 52,357

    squirrel
    Member

    What is the rest of the wiring on the car now? Is it all original? Or an aftermarket harness?
     
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  3. oldiron 440
    Joined: Dec 12, 2018
    Posts: 3,050

    oldiron 440
    Member

    The harness is original I was planning on having a separate fuse block for my ignition and fuel with all new wiring coming off the battery. The car is a low mile garage kept cream puff.
     
  4. Oldiron, I did a GM 1 wire on my Buick. I simply hooked the alternator output wire to the Bat wire on the regulator. No reason the regulator can't be removed. I then bypassed the Amp/charge gauge by changing the Bat wire into the gauge to the outlet post. Installed a volt meter. Your Ford should work much the same way.

    Ben
     

  5. jimmy six
    Joined: Mar 21, 2006
    Posts: 12,172

    jimmy six
    ALLIANCE MEMBER

    I have a GM style Powermaster 100 amp 1 wire alternator on my 56 Ford which had the same 30-40 amp generator. They have instructions on their website to show how to connect what you have to the stock wiring connection on the regulator and actually keep your idiot light if you want. The factory regulator becomes a junction point only. You may need to search a bit or go to a store like Summit where they show the instructions if you look up Powermaster alternator to buy.
    It was easy and has been trouble free and I kept the light. Be sure to ground the case.
     
    oldiron 440 likes this.
  6. oldiron 440
    Joined: Dec 12, 2018
    Posts: 3,050

    oldiron 440
    Member

    I guess the thing that concerns me is the instructions say to run either 4 or 6 gage wire to the battery with a breaker or fuse inline. Everything is out in the shop I'm going to go out and get it so I know what I'm talking about.
     
  7. PhilA
    Joined: Sep 6, 2018
    Posts: 1,719

    PhilA
    ALLIANCE MEMBER

    Yup, the stock wiring isn't up to task of providing an extended high current flow- a half dead battery, high engine RPM... The battery will sink a huge current long enough for the stock wiring harness to get disturbingly warm.
    Note that the wire gauge seems to be quite high- they are making the (usually correct) assumption that the main charge wire will be bundled up in a harness, which reduces the capability of the wire to remain cool, requiring a larger gauge wire than hanging in "free air", aka run by itself, suspended by P-clips etc.

    Make sure you upgrade the main charge path, it is worth the work.
     
  8. B.A.KING
    Joined: Apr 6, 2005
    Posts: 4,033

    B.A.KING
    Member

    I dont have a number, but contact Mad Electrical.com. He has everything you need to make the correct swap. Very helpful.
     
  9. I can give more detail as I've done this swap. Mine was a '64 Comet so there are a few differences (ammeter, not an idiot light) but it should be mostly the same. You won't be able to use a 'fuse panel' as these circuits won't all connect in the same place. Unified fuse panels were still a year away at Ford....
    This will be the least invasive way to do this, requiring minimal changes.

    Starting at the regulator, you'll find two wires connected to both the 'bat' terminal and 'arm' terminal. You can leave the regulator in place as a junction point if you wish. The two wires on the 'bat' terminal need to stay connected together; one comes from the starter solenoid, the other is the main power feed to the harness. Of the two on the 'arm' terminal, only one will be used for sure. One goes to the generator; this may be abandoned. The other is the feed to the idiot light and can be used for more than one thing, more on this below. All other wires connected to the regulator will be unused.

    Connecting the alternator. Pretty simple if it's a one-wire; connect the 'bat' terminal to the battery side of the solenoid. If the alternator doesn't support connecting an idiot light, you're done. The above wire that 'may' be abandoned? It now is official. If you can connect the light (and want to), in this case connect the wire from the 'arm' terminal and the idiot light wiring is done. No light, install a voltmeter to monitor the charging system. I personally wouldn't worry about a fuse on the alternator output as it won't be 'bundled' with any of the harness.

    Connecting the ignition. Not quite as simple, but close. I'm assuming you're using an MSD 6A type box, so connect your red power lead to that same 'bat' terminal and ground the black one. You do need a 'trigger' wire connected at the ignition terminal on the ignition switch to 'turn on' the box, and you have a couple of choices. If you used the idiot light, you can retask the existing ignition power wire for trigger power, but you do need to intercept the wire ahead of the ballast resistor. If you didn't use the light, you can re-task the light wire for the trigger but will need to bypass the light. You'll need to cut the two wires connected to the light and splice them together. All the rest of the MSD ignition wiring will remain in the engine compartment, route as desired. I'll note that you don't need a ballast resistor with these ignitions, even with the stock coil.

    The fuel pump power should be connected to the ignition terminal at the ignition switch. If you didn't use the idiot light and used that wire for the trigger wire, you can retask the 'old' ignition circuit for the fuel pump (again, ahead of the ballast resistor) after verifying the circuit amps needed. Install an inline fuse for protection. The stereo should be connected to the 'acc' terminal at the switch. This wire may be already present even if no radio was installed new. Again, use an inline fuse. If you're using a big high-watt amp, follow the directions of the manufacturer for power connection.

    Again, this is the least invasive way to do this. You could 'improve' this, but that will require modding the existing harness and once you start that it will probably be nearly as easy to just rewire the car with a new harness and would certainly give a less-hacked install. This is how I did my Comet and it was dead-nuts reliable the whole time I owned it.

    A few final details. If you have the original motor still in the car, there are few more things to check. One, Ford changed the size of the threaded holes in the heads in '65, enlarging them from 3/8" to 7/16". Ford found the 3/8 weren't quite up to the task, so you'll need to drill/tap the alternator pivot bolt mounting hole in the head to 7/16". You'll need a regular and bottom tap for this, as well as the right tapping drill. Don't substitute a 3/8, those will break. The other thing to check is the water pump. Ford changed one of the bolt bosses on the pump with the alternator switch in '65. The '62-65 aluminum pumps are completely different from the later ones. If the pump is the 62-64 OEM design, you'll need to put some washers under one of the mounting points on the upper mounting bracket. All the replacement pumps I've seen are the '65 design, no washers needed. Use the '65-70 289/302 style mounting, all of the Mustang vendors sell the brackets/bolt/spacer if you don't have them.
     
    ffr1222k, Budget36, jimmy six and 3 others like this.
  10. oldiron 440
    Joined: Dec 12, 2018
    Posts: 3,050

    oldiron 440
    Member

    Thanks this will be a big help
     
  11. jimmy six
    Joined: Mar 21, 2006
    Posts: 12,172

    jimmy six
    ALLIANCE MEMBER

    100 amp alternators recommend a #8 AWG wire and 150 amp a #6 AWG.
     
  12. Mr48chev
    Joined: Dec 28, 2007
    Posts: 31,838

    Mr48chev
    ALLIANCE MEMBER

    I'm not a fan of one wire alternators unles you use them where they were originally intended on a farm tractor with a magnito ignition.
    Other than that it would be the simplest setup on that Ford as you can run the wire from the alternator directly to the battery or to a connection that runs directly to the battery and not have the power running directly though the igniton system.

    No matter what the amp rating an alternator or generator that is working right with a good working regulator is only going to put out the volts and amps that the system demands out of it. Yes it will charge harder on a dead battery than on a fully charged battery but it is only going to charge what the battery asks for. Any add on pieces like the electric fuel pump can be run off a relay if you think the amp draw is too high but my guess is that few electric pumps draw more than ten amps. A Holley Red 97 GPH pump that is way overkill on 99.9 % of street cars only draws 2 amps. According to MSD most of their systems draw a max of 10 amps.
    If you have an electic fan or a big sound system with an amp then you need those 150 amps .

    To me on that car the best way to go is to follow what Gimpy posted in post 6 in answer to a similar question several years ago with real nifty FORD related diagrams. Save the one wire, buy a proper Ford alternator and matching regulator and follow the directions.
    Customs - generator to alternator conversion | The H.A.M.B. (jalopyjournal.com)

    I've never been much on post 1957 Fords that weren't trucks but have had friends with early 60's rigs that changed them to alternator in the 80's and 90's using similar directions.
     
    oldiron 440 likes this.
  13. oldiron 440
    Joined: Dec 12, 2018
    Posts: 3,050

    oldiron 440
    Member

    Thanks I can see why the 3G alternator swap is so popular, I'm not crazy about the looks but I believe they came on 93 5.0s so they should fit my aplacation. I like the idea of the alternator triggered to start charging and the idiot light working. No need for the external regulator either.
     
    Last edited: Nov 24, 2022
  14. FishFry
    Joined: Oct 27, 2022
    Posts: 152

    FishFry
    Member

    So basically like this?

    ammeter-schematic.jpg
     
  15. 48fordor
    Joined: Jan 16, 2009
    Posts: 143

    48fordor
    Member
    from York, PA

    When I converted to a 3G I looked at the Ford wiring diagrams from the cars that used the 3G and installed a MEGA Fuse (Littelfuse trade name) in the same location Ford did. If that fuse and location worked in the OEM application I thought it was good enough for me. I did significantly oversize the lead to the alternator to avoid voltage drop.
     
  16. MeanGene427
    Joined: Dec 15, 2010
    Posts: 2,286

    MeanGene427
    Member
    from Napa

    3Ginstall.jpg

    The second one is for a 1-wire Powermaster 3G
     

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