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6v Generator vs 12v alternator


OUTFXD

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I have been running a 6 volt POS ground alternator for 15 or more years. I have a six volt electric pusher fan that I use now and then.

 

I have never had a problem with it in 15 years and about 70K miles. I strongly recommend an alternator if you are using an Optima Battery. See my posts from 17 years ago or so to read up on that.

 

James

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Hoovers suck if I am not mistaken....?

 

I can see this on a modified car or one with questionable exchange air or water at the radiator and as a preventive measure on towing or long hauls on a steep grade.  T hey have their uses and advantages....

 

My British van build incorporates a super slim electric fan as a pusher as the larger engine install really has not much room for the standard engine driven fan.  Of course this is not stock, would never want it stock...as I could not be happy at 62 MPH at mega-revs

Edited by Plymouthy Adams
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Ok I will throw in my worthless 2 cents. 

Parasitic draw is real. You can eliminate it if you are building a race car with no cooling or charging system.

 

I would say 12 volt probably would be least parasitic draw for a few reasons.

1, electric fan. You could possibly just leave it off while driving, Just turn it on at long traffic lights when needed. Less parasitic draw then a mechanical fan

2, LED lights. (I hate them) they take less juice to run, means less time the alternator is charging.

3, More options for amps on a alternator ... get a 100 amp alt, will charge your battery lickity  split, less parasitic draw.

4, I would venture to say, a modern alt would have better smoother bearings then a 70 year old jenny with a worn shaft ... Less parasitic draw.

 

IMHO the op is not really interested in trying to stay & look original if willing to install a electric fan ... I'm cool with that, think I am going 12 volt also.

I think between 6 or 12 volt, a real scientific study would show 12 volt winning parasitic draw.

 

I just find it interesting the electrical question was written around parasitic draw.

Makes me wonder if the op is more interested in building a Hot Rod racer then a stock classic. I'm fine with that.

Choosing the correct transmission & rear end can remove a lot of parasitic draw. Much more then the electrical system.

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I plan on keeping the car rather original looking  on the outside.  I do plan on upgrading to  LEDs but want ones that look like original lights,  Not interested in "Angel Eyes" or projector  lights.  I am not terribly concerned with keeping the engine compartment 100% original looking (Though I have put thought to having the 6v generator rewound to 12v neg ground).  I am interested in decreasing the Parasitic load of on the motor as a means to increase Efficiency, Performance and lessen Emissions.

 

I have considered upgrading to a overdrive transmition,  though that would be a project Whaaaaaaaaay down the line.

 

And yes, I know a flathead motor is not a good starting platform for an efficiency build.  but I just love how smooth they run!  so I guess you could say I am just taking what I have and making it better.

Edited by OUTFXD
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You will get better and worth while efficiency from a quality tune up, bump in compression, and even a pertronix module in the distributor.

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Tune up was a given, Petronix is already in the plan.  Had thought about milling the head to bump up compression but that needs further investigation. all great suggestions though!

Edited by OUTFXD
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Trying to think of a proper example for mechanical parasitic draw.

Lets imagine a 727 transmission and a 8.3/4 dodge rear end connected to a flathead 6 engine ... not even sure if it is possible to install the 727.

The result of the heavy transmission & rear end would almost make the car undriveable.  Just all the weight of transferring the horsepower from the crank to the wheels.

 

Now if you installed a lightweight T-5 transmission and a light Mopar 7.25 rear end, there would be less parasitic loss.

 

Same time the factory overdrive transmission will present more parasitic loss then any electrical problems.

 

I think what you are concerned with is torque.  People with the overdrive love the performance of the flathead 0-60 mph & driving down the freeway.

Not a Hot Rod but gets the job done.

And it would not bother these cars if they were 6 or 12 volt. Simply would not be a noticeable difference in performance.

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insofar as Transmition/rear end, I am mainly  concerned with lowering RPMs at cruise on the freeway. I didnt know the factory overdrive was such a dog!

 

Another topic.  Petronix vs 70s Mopar Electronic Ignition.  I read an article about swapping our stock innards into a slant six Distributor.  Seems like that would be a great way to put Tried and true Electronic Ignition into the car.  However it would be WAAAAAAAY more complicated than swapping in a petronix Mag trigger kit.  Thoughts?

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not to mention the Mopar you can walk into a store and walk out with repair parts if needed...I can really see the coin toss needed here....(being snarky...lol)  to me those wishing to stray from stock points, I see no need to leave Mopar...

Edited by Plymouthy Adams
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1 hour ago, OUTFXD said:

Petronix vs 70s Mopar Electronic Ignition.  I read an article about swapping our stock innards into a slant six Distributor.  Seems like that would be a great way to put Tried and true Electronic Ignition into the car.  However it would be WAAAAAAAY more complicated than swapping in a petronix Mag trigger kit.  Thoughts?

It's not complicated at all. I used a long bolt chucked in a cordless drill as a redneck lathe to slightly reduce the OD of the /6 housing. Once you get it to fit in the block the rest is just basic dist reassembling and installation

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13 minutes ago, Young Ed said:

It's not complicated at all. I used a long bolt chucked in a cordless drill as a redneck lathe to slightly reduce the OD of the /6 housing. Once you get it to fit in the block the rest is just basic dist reassembling and installation

True true!  I was thinking more along the lines of wiring for  the old EI system.

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I have all the parts to do this swap.  But I am not going to use the Mopar control box.  Using a GM HEI module and a Ford coil.  Seems that's the hot combo these days.  Probably going to use the EFI to control the ignition, once I get the fueling sorted.

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