1 wire alternator installation questions..
 

Hello guys.

I need a bit of help on the following.

1940 Ford
Car is 12 volt, negative ground.


I would like to install 12 volt, self-regulated 1 wire alternator with correct shaft for large flathead belt pulley.

1 What is the part number for an appropriate 65 amp internally regulated (1) wire alternator to fit the sling-shot style bracket for the flathead?

2 What is the proper wiring set up for this application? (not using stock regulator).

3 Would like to work with someone who has done this with good results.

4 Results should be an alternator that charges around 13.8 with a new battery +/-.

Re: 1 wire alternator installation questions..
 

You will likely get a number of different suggestions, but I believe Powermaster makes what you are looking for. Check pages 58 and 59. I've run their 6V + ground on my 59AB in my '46 Coupe for the last three years with no problems so far.

http://www.powermastermotorsports.com/catalog.html#

Re: 1 wire alternator installation questions..
 

https://www.dbelectrical.com/product...wide-belt.html




Jack E/NJ

Re: 1 wire alternator installation questions..
 

Very helpful, thank you.

Re: 1 wire alternator installation questions..
 

41PanelMark, On my 1 wire GM alternator I installed yesterday, I also installed a fusible link between the (one wire) terminal on the back of the alternator and the + side of the solenoid. My car is 12v (-) ground.

I think you have to modify or make your own generator bracket
I modified an aftermarket bracket for my one wire GM alternator. You can buy them on line made of steel or aluminum Your belt length will also probably change. Wide belt alternator pulleys are also available.

You might first consider FIRST making a prototype bracket out of wood.

Other folks may have a better idea.

Re: 1 wire alternator installation questions..
 

As stated above, a 10SI is all you need for your application. I would also consider using a small pulley on it to get the charge rate at idle that the alternator is capable of. A street flathead will never wind high enough to damage the alternator. You might have to tweak the alternator case to get the correct belt alignment with the slingshot bracket. The attached picture shows misalignment on an 8BA with truck water pumps. I can't find my "after" picture, but it is evident what needs to be trimmed.

Re: 1 wire alternator installation questions..
 

my 2 cents worth wont go into brands/suppliers etc as im down under but 1 item often overlooked is pully size very important as an altenator that's not spun quick enough wont charge correctly and one thats spun to fast will self destruct very quickly

Re: 1 wire alternator installation questions..
 

I use DB on all my stuff.Starters and alt

Re: 1 wire alternator installation questions..
 

Another thing to consider if using a small pulley is that the original spec belts were not designed to turn that small a radius so you might need a belt with internal or external serrations. (so it is more flexible).

Mart.

Re: 1 wire alternator installation questions..
 

I was going to recommend Randy Rundle of Fifth Ave Garage, but i just seen where he passed away on Feb 1 2021.

Re: 1 wire alternator installation questions..
 

if interested I have a 1 wire, Motorcraft altenator,15v, 40 amp, neg grd, with 1 belt pulley.

Re: 1 wire alternator installation questions..
 

Thanks for all of this guys. I bought a 1 one wire online yesterday.

I am sure that the following will stir up some conversation, my apologies in advance for that.

I currently have new a 3 wire, 10 SI on the engine but no matter what I do that thing puts out 15.0 to 15.5 volts. I have tried locating the sensor wire in various suggested places but no luck. I have a brand new fully charged 12 battery, solenoid, and wiring, just don't want to cook a good battery. I had the alternator tested at NAPA and another parts place. Both printouts show the alternator to be working fine including the regulator.

I have posted on 4 forums about this and have had many suggestions on how to hook it up to make it work correctly or add additional fixtures in line, some of which I have done but still no go. (I don't think that I should have to add regulators, resistors and other to make this thing work).

Thought about buying a pile of internal regulators and trying them until I found one that did not push the 15+ but that is a lot of work and time not to mention more money. Besides NAPA said it tests fine.

Because there too much voltage going to the internally resisted coil I recently installed, (15+ volts) that I am seeing on the positive side, I am still seeing over 12 on the neg side, also good for the points I would imagine.

A lot of guys suggested that I go with the one wire and be done with it so out of pure frustration that is what I am going to try next.

Re: 1 wire alternator installation questions..
 

>>>I currently have new a 3 wire, 10 SI on the engine but no matter what I do that thing puts out 15.0 to 15.5 volts>>>


Depends on where you're measuring it, on if you're using an analog or digital meter, on the ambient temperature. In the wintertime in Colorado I'd say that's in the right range. I'd rather have he 3-wire. You can always convert it to a 1-wire by pigtailing the 2nd sensing terminal directly to the bat output terminal and disconnect the 1st exciter terminal. The voltage should drop some at the battery terminal. Jack E/NJ

Re: 1 wire alternator installation questions..
 

Have you ever considered that whatever device you are using to measure voltage is out of calibration??

Re: 1 wire alternator installation questions..
 

41panelmark: Are you using the stock 1940 gauges? If, so you will have to reduce the incoming voltage to them, unless you have already had the gauges professionally converted to operate on 12V. Have you rerouted the wires that used to connect to your firewall 6V Voltage regulator from your original generator?

When I converted my 40 to 12v I used a Constant Voltage Reducer to reduce the 12V coming to the fuel, temp. and oil pressure gauges to 6 V. To make the 1940 BATT gauge read accurately I had to (using knowledge provided by Flat Ernie) isolate the BATT gauge from the other gauges and installed a 60 ohm resister in the 12V wire feeding the BATT gauge. The info. is in thread below. Might be helpful if you're still using your stock 6V gauges.

https://www.fordbarn.com/forum/showt...olt+conversion

Re: 1 wire alternator installation questions..
 

I just bought a new 12 volt with a 5/8” pulley from DB electrical on ebay . One wire , made for tractors . It uses the gm alternator , it was $57 delivered . Installed using speedways mount . I had just finished installing all new wiring , using Tyree Harris excellent wiring harness . All i did was remove my existing 12 volt generator 30 amp and wired the alternators single wire to the battery . I left the regulator mounted on the fire wall , just for now . After removing the generator and the armature and field wires that go to the regulator ( removed also ) only the battery wire was remaining. I was tempted to mount the alternator wire to this battery terminal since they both go back to the battery but i think the battery was a better choice . In the future ill remove the regulator and safely isolate the wire that went to its battery terminal .
The alternator is 63 amps and has 55 amps of that at 2000 rpm . So far very happy . Mine was 12 volt neg ground to start . Im adding air conditioning so I need a little more amps than the 30 amp 12 volt generator was able to provide.

Re: 1 wire alternator installation questions..
 

All good thoughts guys.

1st, yes we have tried 2 other digital meters and one analogue.

2nd, have tried tying the smaller red wire directly to the large terminal, no luck.

while running with the white wire disconnected the alternator shows no charge as expected, touch the white to any of the positive connections and it kicks off just fine but stays high no matter if the white wire is connected to something or not.

We have also run the smaller (white) sensing wire directly to the bat output side, no luck.

Jack, I would like to know more about the 1st exciter terminal. I am guessing that you are referring to the smaller red wire here and not the white?

3rd, I have a voltage reducer for the gauges and they appear to function normally.

1940, good hint on the battery gauge function. I will check the link you posted, thank you.

Re: 1 wire alternator installation questions..
 

>>>Jack, I would like to know more about the 1st exciter terminal. I am guessing that you are referring to the smaller red wire here and not the white?>>>


The exciter wire spade terminal to the ignition switch is not used on a 3- to 1-wire conversion. For this reason you may have to blip the engine a bit on starting so the alternator self-excites from residual magnetism. This is typical for 1-wire operation. Only the sensor wire spade terminal is connected to the alternator main battery output terminal. 15 +/- volts is unlikely to cook a battery. Jack E/NJ


https://www.fordbarn.com/forum/attac...1&d=1612733025

Re: 1 wire alternator installation questions..
 

Thank you Jack. This will be part of the next test.