1957 Buick Wiring Diagram with modern Alternator, HEI Distributor, Mini-Starter

PHAWK33

Member
Hello Everybody!
I am restoring a 57 Century and have made some modifications (improvements) over some of the older electrical components in the engine bay:
  1. New 100 Amp one-wire Alternator with internal voltage regulation
  2. New 1400 Watt high-torque mini-starter
  3. New HEI Distributor
  4. Eliminated the accelerator starter switch to a momentary-contact button switch on the instrument panel
  5. Replaced the vacuum-driven wiper system with an electrical Wiper Motor System
  6. Moved the Battery to the trunk for improved weight distribution
I have drawn a new wiring diagram with the affected systems as shown below. I would love to hear any comments, suggestions or ideas from the community. Thanks for your time!
Joe in Richmond, VA

Wiring Diagram.JPG
 
Joe, good to see the 1 wire alternator and the HEI. I have a couple questions. Hopefully in the correct order. Jct block posts connected? Assuming so. Personally, I use an 8ga. from alternator. I question the 2ga from/to battery and 1ga to starter. I see no need for 1ga to starter while 2ga [ smaller ] from battery. Where is battery grounded? If I am reading the diagram correctly, the Amp meter is redundant. I am a proponent of larger wire is better. IF I had mounted my battery in the trunk, I would have used an 0 [aught] from the battery, as well as a ground of the same size back to the engine somewhere.

Ben
 
I agree the largest wire should be the + from the starter to the junction block and on to the starter. I would think a good ground from the battery to the frame would do the job just fine and use that as a base for all grounding.
As HEI is uses 12V at all times, and you are using a start button and not a key start, you can probably eliminate the pink from the solenoid. The pink from the solenoid is there only to supply 12V during cranking. You should remove the resistor between the ignition switch and the coil and it should get the 12V all the time from that switch.
 
Joe, good to see the 1 wire alternator and the HEI. I have a couple questions. Hopefully in the correct order. Jct block posts connected? Assuming so. Personally, I use an 8ga. from alternator. I question the 2ga from/to battery and 1ga to starter. I see no need for 1ga to starter while 2ga [ smaller ] from battery. Where is battery grounded? If I am reading the diagram correctly, the Amp meter is redundant. I am a proponent of larger wire is better. IF I had mounted my battery in the trunk, I would have used an 0 [aught] from the battery, as well as a ground of the same size back to the engine somewhere.

Ben
Ben, Thank you for your response.
* The junction posts are not connected other than indirectly in the same manner as thru the old voltage regulator (which has been eliminated).
* The Alternator to post wire has been upgraded to 8 Ga, thank you for pointing that out.
* The battery to starter cable is a 2 Ga because the 2 Ga cable is rated to carry 150 Amps at 15' length (150 Amps delivers 1800 Watts which is more than ample to power the 1400 Watt Starter - the maximum load).
* The 1 Ga cable from the Jct Block to the starter is overkill but I had it available so it was used.
* The Battery in the trunk is strap-grounded to the frame. The engine is also strap-grounded to the frame.
* The Ammeter was left intact because it serves a legitimate purpose as per original design by Buick.
Again, thanks for taking the time to look at my diagram!
Joe
 
I agree the largest wire should be the + from the starter to the junction block and on to the starter. I would think a good ground from the battery to the frame would do the job just fine and use that as a base for all grounding.
As HEI is uses 12V at all times, and you are using a start button and not a key start, you can probably eliminate the pink from the solenoid. The pink from the solenoid is there only to supply 12V during cranking. You should remove the resistor between the ignition switch and the coil and it should get the 12V all the time from that switch.
Bob,
Thank you for looking at my installation.
* The 18G Pink from the starter switch is connected to the starter relay and it energizes the contact at the relay to get the solenoid engaged thru the 10G Black.
* The HEI is connected to the ignition switch where it gets its 12 V directly since I already eliminated the resistor system used by Buick.
Please feel free to let me know if my reasoning is incorrect.
Thanks again,

Joe
 
Joe,
Here are some more ideas:

1. The 18 LGreen wire at pin 4 of the starter relay needs to be rerouted from the Jct Block to ground. This would be a good place to add a secret starter kill switch for added security if you like.

The wiring as shown matches the original. The change from generator to alternator introduces some complications. The generator armature winding on terminal A acted as a short to ground when the generator wasn't turning. The LGreen wire was then grounded as long as the generator was stopped.

With 12 V applied at pin 3, the starter relay coil would get 12V and pull in the relay. Once the engine fired and the generator started turning, voltage at pin 4 went to 12 V same as terminal A of the generator. This was a safety circuit that made the starter relay drop out in case the engine started and the accelerator switch jammed closed. Since the accelerator switch is gone, this safety circuit is not needed now.

The alternator output windings appear as an open circuit at the output terminal when the unit is stopped. The internal diodes prevent any + voltage applied at the output terminal from flowing back down through the windings. So connecting the LGreen wire here would not ever energize the starter relay coil.

2. The horns look to be mislabeled as headlights.

3. You probably already know this, but caution should be applied if ever adding any new large loads. The alternator can produce 100 Amp continuously but the rest of the system is still designed for the 35 Amp generator. Any large new feed could be taken right at the alternator terminal to avoid problems. New loads could be controlled by existing switches by using interposing relays like on a modern car.
 
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Joe,
Here are some more ideas:

1. The 18 LGreen wire at pin 4 of the starter relay needs to be rerouted from the Jct Block to ground. This would be a good place to add a secret starter kill switch for added security if you like.

The wiring as shown matches the original. The change from generator to alternator introduces some complications. The generator armature winding on terminal A acted as a short to ground when the generator wasn't turning. The LGreen wire was then grounded as long as the generator was stopped.

With 12 V applied at pin 3, the starter relay coil would get 12V and pull in the relay. Once the engine fired and the generator started turning, voltage at pin 4 went to 12 V same as terminal A of the generator. This was a safety circuit that made the starter relay drop out in case the engine started and the accelerator switch jammed closed. Since the accelerator switch is gone, this safety circuit is not needed now.

The alternator output windings appear as an open circuit at the output terminal when the unit is stopped. The internal diodes prevent any + voltage applied at the output terminal from flowing back down through the windings. So connecting the LGreen wire here would not ever energize the starter relay coil.

2. The horns look to be mislabeled as headlights.

3. You probably already know this, but caution should be applied if ever adding any new large loads. The alternator can produce 100 Amp continuously but the rest of the system is still designed for the 35 Amp generator. Any large new feed could be taken right at the alternator terminal to avoid problems. New loads could be controlled by existing switches by using interposing relays like on a modern car.
Hi Todd,
Thank you very much for your thoughtful analysis.
1. If I understand you correctly, I will need to ground Terminal 4 from the Starter Relay and NOT connect it to the Alternator output, right?
2. The headlights are only showing the connection to the horns at the terminal blocks in the headlights
3. Understood. The only added load is that of the electric windshield motor which draws 6 amps.
Please confirm item 1. Thanks again for your time!
Joe
 
Tell me again how eliminating the cool smooth factory foot starter relay is somehow an improvement via a hacked external push button ? Personally no, don't think so. You know there is a simple way to keep the foot switch when going with a 1-wire alternator. Go over to AACA Buick group and do a search and find it. Food for thought.
 
Hi Todd,
Thank you very much for your thoughtful analysis.
1. If I understand you correctly, I will need to ground Terminal 4 from the Starter Relay and NOT connect it to the Alternator output, right?
2. The headlights are only showing the connection to the horns at the terminal blocks in the headlights
3. Understood. The only added load is that of the electric windshield motor which draws 6 amps.
Please confirm item 1. Thanks again for your time!
Joe
Correct. There will be only one wire on pin 4. And it goes to ground.
 
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