6V to 12V Electrical Conversion

[Slavs]

I have an early 67 1600 where the previous owner had, unfortunately , done a number of "Upgrades" to the car. The 6V electrical was converted to 12V. He also dropped in a 2L motor and 320i overdrive and converted the 4.11 diff to limited slip. The car drives well, but I've had issues with the negative terminal which I'm always cleaning. I started to look at the electrical wiring and noticed that the old original 6V voltage regulator was left in place. I'm using a 12V battery, bulbs and instruments. And he also installed a Bosch 90amp Alternator  with internal voltage regulator as used on the 1985-92 VW Golf and Jetta. So, what is my 6V regulator doing at this point ?

 

I'm not an electrical guru, and I was wondering what is it that is done during the 6V to 12V conversion ? Are the same wires left in place while the bulbs , instruments and other electrical components are replaced ? Or is it that the wiring harness must also be replaced.

 

Before I acquired this car, it was passed around various BMW specialists in Southern California who performed the conversions. Unfortunately, the original motor was lost during the process. I've been seriously considering reverting back to the stock drive train and electrical on this car while leaving in place the mild suspension upgrades. And, I was trying to figure out what exactly was done to the wiring , if anything.

 

Slavs

[Son of Marty]

That 6v regulator is a leftover from the old days I can't even conceive how it would operate in your 12v system, my first step would be to rewire the alternator the + output has too large a wire jammed into a smaller ring terminal and the ground wire looks to be to small to do the job, replace both 10 gauge wire with the proper terminals and then heat shrink the connections, I'll let Tom (minty) comment on the positive battery wire at the battery, when your car was 6 volt they had to use bigger wires throughout the system so unless it's been hacked it should be good.

 

Great looking car is that Bristol Gray?

[Slavs]

10 minutes ago, Son of Marty said:

Great looking car is that Bristol Gray?

Yes, its Bristol Grey.

Thanks for your input.

Edited August 8, 2020 by Slavs

[Mike Self]

One of the perks from changing from 6 to 12 volts was the ability to use smaller diameter wires to perform the same function. amperage (current draw) is wattage (current consumption) divided by voltage, so to achieve the same number of watts, a six volt system must draw twice as many amps.  For example, a 6 volt starter motor will draw 400 amps to achieve the same horsepower as a 200 amp 12 volt starter.  Fewer amps = smaller wires.  So the wiring in a six volt car is more than enough to handle a 12 volt conversion.  Just don't go the other way.  

 

Hopefully the guy(s) that converted your car did the whole thing--bulbs, heater blower motor, windshield wiper motor, fuel and temp gauges, windshield washer pump etc.  Six volt accessories run on 12 volts won't last long, or in the case of gauges, may not work at all.

 

Besides the very cool color, those are even cooler wheels.  Very period.

 

mike

[Slavs]

1 hour ago, Mike Self said:

Besides the very cool color, those are even cooler wheels.  Very period.

Thanks for the explanation, Mike.

 

I can crunch numbers, just need to educate myself with electricity. Higher amperage required to achieve same wattage with 6V system requires thicker wires, makes sense. I should have grabbed all the 6V parts when these cars  littered the junkyards. Those parts are pretty rare, now.

 

The wheels are English Cosmic wheels from the period. They are 5 1/2" x 13" with ET19 offset. But, they were also made in a narrower size.

[Mike Self]

14 minutes ago, Slavs said:

I can crunch numbers, just need to educate myself with electricity.

If you think of electricity as water flowing through a hose or pipe, it's easy.  Voltage is the pressure; amperage is the amount; wattage is the work that's done by the water at its destination.  

 

Disregarding friction, you can get twice as much water out the hose at 50 psi than at 25 psi.  You can get twice as much water--at the same pressure--through a two inch pipe as through a one inch pipe.  And you'll get the same amount of work from a flow of water through a one inch pipe at 50 psi as you will from a two inch pipe at 25 psi...

 

mike

[Slavs]

Given the uniqueness of these early cars, I would have left the car all stock if I was the previous owner. Maybe I would have just tightened up the suspension a little bit. My car is an example of what happened to most of these early cars.

 

According to the previous owner the BMW shops were often the driving force, convincing him to OK! the "Upgrades". They kept the original motor, telling him it was just way too under-powered and sold him a stock 2 liter. When the Solex carb went "South" they sold him on the Weber 38/38. And. that carb was a very bad match for the motor. The torque range was decreased where it was all or nothing. I'm pretty good with carbs, and from my experience I think that a properly jetted and choked set of DCOE sidedrafts feel a lot better, even on a stock motor. So, that's the first thing I replaced, opting for a 32/36 and eventually fitting an original Solex 40 PDSI. Upon examining the electrical a little closer I'm convinced most of it was borrowed from a 68-69 era 1600 or 2002. This makes sense as the conversion was performed at an 02 shop which also doubled as an 02 wrecking yard. They also removed the original front seats, replacing them with later seats with headrests. I got rid of them and installed a pair of seats I removed from a 66 1600 which I found at the boneyard. I've been going through this car while attempting to bring back as much of its original character as possible. Next in line is the motor. Thanks to a good lad on this FAQ who donated a factory replacement 1600 block with no serial numbers, a very nice crank and early transmission. I'm assembling a motor for it with NOS Mahle pistons and a NOS 1600 118 head. I'll probably be one of the very few people to be removing a 5 speed OD and replacing it with an early 4 speed Porsche syncroe box. I can always throw the 5 speed and 2 liter into a later car such as a 74 02 I have laying around, parked for years. I think I'll tackle the electrical to revert it to 6 volt. That's my vision for the car.

 

As far as the 6V to 12V switch, some BMWs such as the NK2000Ti were 12V in 66, but others were still 6V. I think the 1800ti was still 6V. And the 1600-2 seems to have been 6V all the way through 67.

 

Slavs

Edited August 8, 2020 by Slavs

[Conserv]

3 hours ago, Slavs said:

 

... As far as the 6V to 12V switch, some BMWs such as the NK2000Ti were 12V in 66, but others were still 6V. I think the 1800ti was still 6V. And the 1600-2 seems to have been 6V all the way through 67....

 

Slavs,

 

The 1600-2 was changed to 12-volt electricals at VIN 1533868 (manufactured August 18, 1967). So the U.S. 1968 models, which began very shortly after this, were all 12-volt cars, as were all 1600ti’s.

 

My only complaint with my 6-volt 1600-2 was starting the car when the temperature dropped to about 20 degrees, or so. And that problem shouldn’t affect you! I’d love to know that someone restored an early 1600-2 to its original, and eminently good, original configuration!

 

Regards,

 

Steve

 

[AustrianVespaGuy]

18 hours ago, Mike Self said:

You can get twice as much water--at the same pressure--through a two inch pipe as through a one inch pipe

Technically though you'd get 4x as much flow/work, since with the whole pi*r^2 thing, the area would be quadrupled.  Sorry @Mike Self not about to let you get away with sloppy math!  But the water analogy is always great though, and can even be expanded upon: resistors are like restrictions, potentiometers are like valves, capacitors are like tanks. . . damn, anyone got good ones for diodes or inductors?

[Mike Self]

11 hours ago, AustrianVespaGuy said:

Technically though you'd get 4x as much flow/work, since with the whole pi*r^2 thing, the area would be quadrupled.  Sorry @Mike Self not about to let you get away with sloppy math!

 

Hey!  I was a history major and barely got thru my math requirements to graduate! ? So I feel pretty smug when I can understand--not to mention explain--most anything technical.  But my analogy does explain why 6 volt systems need larger diameter wires to do the same work as a 12 volt system...the practical stuff I get; it's the theory that sometimes bogs me down.  But on the other hand, can you engineers discourse on the importance of the Chaco War? ?

 

mike

[Healey3000]

On 8/8/2020 at 5:26 PM, AustrianVespaGuy said:

But the water analogy is always great though, and can even be expanded upon: resistors are like restrictions, potentiometers are like valves, capacitors are like tanks. . . damn, anyone got good ones for diodes or inductors?

Diode = check valve

Inductor = water wheel connected to a flywheel

 

That inductor analogy takes some mind-bending ?

[Healey3000]

On 8/9/2020 at 4:55 AM, Mike Self said:

 

But on the other hand, can you engineers discourse on the importance of the Chaco War? ?

 

mike

I had to look that up!  I prefer The Milagro Beanfield War ?

[Slavs]

What about the “Soccer War” ?

[landon]

I love that car Slavs. Great color and reminds me of my first car - a 1968 1600-2. 

If you want to sell I'd offer $1400.00 today!  ?

[MrAdams]

dude really? I am in a very similar situation

 

My car has a 12v battery, original generator .

 

 

i am trying to figure it out