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1966 V8 (302ci with MSD ignition and coil - AGM battery, stock alternator)

Just noticed that my ammeter needle never moves. I can switch on the AC and the headlights, and it still doesn't move, whether I'm idling or at speed.

Shouldn't that needle deflect at least when I engage something electrical?

Thanks.
When I did a conversion to a 66 gauge cluster some 17 years ago, I used a dedicated wire and a 10 watt 18 ohm resistor and a fuse holder with a 2 amp fuse. I tried several ohm ratings and settled on 18 ohms which made the gauge responsive but not too responsive. The gauge will deflect fully with less than an amp across it and they will fry if the battery main terminal is degraded or disconnected...it was one bad design, but I safeguarded it. Still working great years later. The retro voltage gauge though is a nice alternative that I don't think was available 17 years ago.
 

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The first two pictures NEFaurora posted are actually my instrument cluster. The third is a Rocketman conversion I believe. To answer your question, the wheel is a Nardi product.
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Discussion Starter #23
When I did a conversion to a 66 gauge cluster some 17 years ago, I used a dedicated wire and a 10 watt 18 ohm resistor and a fuse holder with a 2 amp fuse. I tried several ohm ratings and settled on 18 ohms which made the gauge responsive but not too responsive. The gauge will deflect fully with less than an amp across it. Still working great years later.
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Wow! That's what imma talking about!! Thank you! Worth a try.

So, for a 4th grader electrician, I run a wire from WHERE, to a 2A fuse and fuse holder, to the 10V 18 ohm resistor, to a blade connector to one side of the ammeter, and the other side of the ammeter goes to ground?
 

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Wow! That's what imma talking about!! Thank you! Worth a try.

So, for a 4th grader electrician, I run a wire from WHERE, to a 2A fuse and fuse holder, to the 10V 18 ohm resistor, to a blade connector to one side of the ammeter, and the other side of the ammeter goes to ground?
If I rememer correctly, the ammeter circuit is in parallel with the 10 gauge black wire that goes between the alternator output and the + battery terminal. So you run one wire from the alternator output terminal to one of the ammeter posts. Then another wire running from the battery + terminal or the + battery terminal of the starter solenoid to a 10 watt 18 ohm resistor and then a fuse holder with a 2 amp fuse in it and then that goes to the other ammeter post. If the ammeter deflects the wrong way, then swap the wires on the ammeter posts. Your car could be different than mine and a different ohm rating for the 10 watt resistor may be needed. Make sure the 10 gauge wire from the ammeter output to the battery is in good condition first or you'll keep blowing fuses.
 
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