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Alternator Question
#1
When I use the turn signal the headlights dim, same with the cockpit
fan, etc. I am thinking I need a new alternator. The battery is less
than one year old and regulator was recently replaced. The one now
installed is ~65 amp(?) and don't know how old but not factory
original. I assume installing a 100 amp unit is not a problem. The
question is do I need one with single wire and internally regulated?
Summit Racing has one for $105 and NPD for $265.

mike

[Image: 1_11_11_13_11_50_27.png]
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#2
From the factory, most our Mustangs were equipped with an Autolite 55 AMP alternator that ist externally regulated. The regulator is a box located on the right fender apron, close to the starter solenoid.

Converting the car to an internally regulated alternator with a one-wire hookup is possible. The stock regulator will then have to go.
Under normal driving conditions and with standard equipment, the car does not need 100 AMP to properly operate. If you have added power equiment and large stereo amplifiers, 100 AMP and more can make sense.

To check the alternator performance and regulator condition do the following:
Start the car and bring it to operating temperature. Hook up a Voltmeter to the alternator circuitry. Turn on as many power consumers in the car as possible, headlights, high-beam, blower, radio, interior lights, ...
Observe the voltage. If it goes down significantly from 14 Volts, chances are high that your alternator or regulator are shot. If the fluctuation is only small, the regulator may be defective. Sometimes, mechanical regulators (used by Ford back then) begin to operate faulty when aging. They cannot compensate for quick changes in power demand any more.

I had this twice on Ford cars. I fixed it by using an electronic regulator of high quality.
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#3
Unfortunately the replacements for our stock external regulators suck. They are the typical china made crap. I converted to an 95 amp internal regulated alternator and never looked back. Not a single issue since.
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#4
West Coast Classic Cougar for electronic VR no more probs.
  Reply
#5
Spechti;155733 Wrote:From the factory, most our Mustangs were equipped with an Autolite 55 AMP alternator that ist externally regulated. The regulator is a box located on the right fender apron, close to the starter solenoid.

Converting the car to an internally regulated alternator with a one-wire hookup is possible. The stock regulator will then have to go.
Under normal driving conditions and with standard equipment, the car does not need 100 AMP to properly operate. If you have added power equiment and large stereo amplifiers, 100 AMP and more can make sense.

To check the alternator performance and regulator condition do the following:
Start the car and bring it to operating temperature. Hook up a Voltmeter to the alternator circuitry. Turn on as many power consumers in the car as possible, headlights, high-beam, blower, radio, interior lights, ...
Observe the voltage. If it goes down significantly from 14 Volts, chances are high that your alternator or regulator are shot. If the fluctuation is only small, the regulator may be defective. Sometimes, mechanical regulators (used by Ford back then) begin to operate faulty when aging. They cannot compensate for quick changes in power demand any more.

I had this twice on Ford cars. I fixed it by using an electronic regulator of high quality.

With engine at idle the voltage at the battery reads 13.72, with
everything turned on it reads 13.18 and this is the regulator currently
installed from Marti Auto

http://www.martiauto.com/itemselection.c...editem=yes

mike
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#6
My electronic regulator from NAPA has also been fine. Doesn't look like original but certainly works for cheap.

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#7
goodnigh;155745 Wrote:
Spechti;155733 Wrote:From the factory, most our Mustangs were equipped with an Autolite 55 AMP alternator that ist externally regulated. The regulator is a box located on the right fender apron, close to the starter solenoid.

Converting the car to an internally regulated alternator with a one-wire hookup is possible. The stock regulator will then have to go.
Under normal driving conditions and with standard equipment, the car does not need 100 AMP to properly operate. If you have added power equiment and large stereo amplifiers, 100 AMP and more can make sense.

To check the alternator performance and regulator condition do the following:
Start the car and bring it to operating temperature. Hook up a Voltmeter to the alternator circuitry. Turn on as many power consumers in the car as possible, headlights, high-beam, blower, radio, interior lights, ...
Observe the voltage. If it goes down significantly from 14 Volts, chances are high that your alternator or regulator are shot. If the fluctuation is only small, the regulator may be defective. Sometimes, mechanical regulators (used by Ford back then) begin to operate faulty when aging. They cannot compensate for quick changes in power demand any more.

I had this twice on Ford cars. I fixed it by using an electronic regulator of high quality.

With engine at idle the voltage at the battery reads 13.72, with
everything turned on it reads 13.18 and this is the regulator currently
installed from Marti Auto

http://www.martiauto.com/itemselection.c...editem=yes

mike

Mike the original looking style concours regulators are very ground sensitive
I see you bought one on my web site, thank you
But as you drive your car daily and have the CA heat - you might be better off with the electronic ones from an auto parts store - you can always paint it blue and get the yellow decal.
It will not be correct but won't be real noticeable if it is dressed up.
Let me know and I can cancel the order if you go the electronic route.
Don

Ohio Mustang Supply
440-949-2556

[Image: oms_sig_banner.jpg]
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#8
OMS;155781 Wrote:Mike the original looking style concours regulators are very ground sensitive
I see you bought one on my web site, thank you
But as you drive your car daily and have the CA heat - you might be better off with the electronic ones from an auto parts store - you can always paint it blue and get the yellow decal.
It will not be correct but won't be real noticeable if it is dressed up.
Let me know and I can cancel the order if you go the electronic route.
Don

No, complete the order. It is better than taking the car to a local
garage. Horror of Horrors!
A drop from 13.8 to 13.1 is not good at idle. If the regulator is not
the problem we will move on.

mike
  Reply
#9
Another issue often overlooked is if the alternator belt is not tight. At idle, a loose belt will slip, allowing the alternator not to put out as much voltage as needed to charge the battery. With the engine at running RPMs, the alternator will spin enough to be good.

Let me check your shorts!
http://midlifeharness.com

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#10
Hey Mike,

Is this something new that it's doing or has it done it forever?
My interior light would dim when I turned on headlights, and everything blinked with the turn signal on.

I'm thinking that a higher output alternator might help, but may not solve the issue.
There is just a huge amount of draw when you turn on the lights because of how they were factory wired.
I ended up putting my headlight power through a relay pack, and used the switch only to trip the relays.
My headlights are way brighter and nothing dims or flickers anymore.
I did pretty much this:
http://www.midnightdsigns.com/james/headlights.htm

It might not solve your issue, but worst case is it will definitely make your headlights brighter.
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