Ammeter to Voltmeter...who does it?

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I tell you what i will also be modifying on the back of the cluster housing. The ground points to the circuit boards. I intend to drill out all the board mounting screw holes in the metal gage housing frame, tap the holes for 10/32 threaded screws, and superglue threaded studs in the tapped holes. I had 2 of the self tapped screws that were stripped in the housing, if i have to modify these for studs, then i may as well modify the remainder. My other option will be to helicoil all the grounding screw holes to a 10/32,:and use some nice stainless steel phillips button head screws.
 
All,

What 12v source are you using to power the new voltmeter?

Is there a How To better than the MAD site to do the rewire of the ammeter?

Thanks,

Marion
 
Your 12V source SHOULD reflect the actual battery voltage. Others on here, as well as myself have discussed the problems with voltage drop in the harness. Even if you bypass the ammeter, the ignition switch / connector, and feed out through the "ignition run" circuit can still have drop, cause overcharging at the battery, and a wrong reading on your voltmeter.

One way around that is to use the original "ignition run" wire out in the engine bay to trigger a relay, then feed the alternator field/ regulator / ignition / etc off the relay. This in most cases will "work around" the remaining voltage drop problem, as well as relieve the under-dash circuit enough that your meter will read more closely

As far as the MAD article, it's as good as any with factory wiring. One thing you must understand, there, is that they were trying to do that mod with as little as possible into the appearance of factory. Part of the reason it was done that way is to provide additional wire capacity (ampacity) into the interior of the car
 
67Dart273,

Thanks for the reply.

I'm thinking about not messing with the dis-aasy and drilling the distribution block and just go in thru the fire wall and use grommets for the power feeds. Get a Sun meter and use it.

Thanks for the wiring info. My engine is out but coming back in a few weeks, with a break in the weather I'm finishing up my issues under the hood to include new steering box.

Marion
 
mario03srt said:
67Dart273,

Thanks for the reply.

I'm thinking about not messing with the dis-aasy and drilling the distribution block and just go in thru the fire wall and use grommets for the power feeds. Get a Sun meter and use it.

Thanks for the wiring info. My engine is out but coming back in a few weeks, with a break in the weather I'm finishing up my issues under the hood to include new steering box.

Marion
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One thing you might do is try to find a photo of how the what was called "fleet police taxi" wiring was done. This was an option for some years that in fact DID run the ammeter wiring through separate grommets in the firewall. This was a factory / dealer mod for the 60? or maybe 65A alternators that provided heavier wiring and bypassed the bulkhead terminals.

This is documented in some of the factory shop manuals in the wiring diagrams. You can download many at MyMopar

Here is a partial screenshot out of the '72 shop manual, for Satellite

65A_zps8yw79eri.jpg


Look over at far right, where it shows the original red / black ammeter wires cut and abandoned
 
All,

Well the steering wheel and instrument cluster are out and the ammeter bypassed. Just came thru the firewall. I have a couple of new questions. Can I use a fuse instead of the fusible link, and if so what is a good amperage type for the 90 amp alt?

Secondly, do I need to splice the new side of the loop from the black lead into the red side before the fuse/fuse link? Can I not just run it to the starter relay? The other end that comes from the ammeter to the new fusible link or fuse that I'm installing. Seems that the circuit is still protected but a little cleaner this way.

I also was thinking of running the two 8 awg power leads to a stud type junction block , then feed the fuse/fusible link to the starter relay. Does anyone have a set up similar to this? Seems clean and organized to me too.

Stud Type Junction Block - Surface Mount - 5/16 Inch Stud

Thanks,

Marion
 
Basically you need a good quality fuse / holder at least as large as the alternator output. Make certain the wire you use is large enough.
 
67Dart273 said:
Basically you need a good quality fuse / holder at least as large as the alternator output. Make certain the wire you use is large enough.
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Hi,
I bought a crackedback alt wire w/ a fusible link. So I'm good there. What about at the starter relay?

Thanks,
Marion
 
Rbob said:
I tried the Cen-Tech and it did not work for me. I ended up going with a Sunpro CP8215 that I got from Amazon. Pretty simple just took the guts out and slipped it in to the spot and put the original face back on.

Curious if you had to stretch the holes out in the housing. When I slipped the gauge into the holes, the needle hits the round center post. I will need to move the gauge up about an 1/8" so that the bottom of the needle does not hit the post.

SunproVolt.jpg
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I ground this part off mine with a rotary file in a high speed straight air grinder to allow the gage needle to swing. Your conversion looks pretty square in there i wouldent move it. If you move it up any further your volt gage internals wont be hidden but will be easily seen. Of course to grind out the spot in your housing for the gage needle to freely swing, you have to remove all the gages from the housing because of metal chips when you grind out the center pin.

I insulated the red feed wire with a plastic grommet going thru the housing, and 2 thin phenolic washers. One on either side of the metal gage housing, but i used metal washers to ground the negative gage stud to the metal housing this way you only have to run one feed wire. You can run that 12v volt gage positive wire right over to the 12v input feed that sends gage cluster power into the voltage regulator in the fuel gage. Remove the stamped nut that holds the fuel gage in the housing that is also the 12v feedcoming in, use a washer, a nut and a ring terminal and tap in.

I also clipped the old needle off the old ammeter, and clipped the needle of the new volt gage short to glue the ammeter needle to it to complete the mod. I also hooked the newly modded volt gage up to a car battery charged to 13.5 volts, checked with an volt ohmmeter, and while the gsge had power running to it , i adjusted the needle where i wanted it to point to by adjusting the potentiometer on the volt gage internals to tune in the pointer

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While in there, why not remove the IVR out of the fuel gage, and wire in a solid state IVR, and install some 5630 LED strip lighting. For more uniform backlighting

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moparmat2000 said:
I ground this part off mine with a rotary file in a high speed straight air grinder to make the gage needle swings. Your conversion looks pretty square in there i wouldent move it. If you move it up any further your volt gage internals wont be hidden but will be easily seen. Of course to grind out the spot in your housing for the gage needle to freely swing, you have to remove all the gages from the housing because of metal chips when you grind out the center pin.

I insulated the red feed wire with a plastic grommet going thru the housing, and 2 thin phenolic washers. One on either side of the metal gage housing, but i used metal washers to ground the negative gage stud to the metal housing this way you only have to run one feed wire. You can run that 12v volt gage positive wire right over to the 12v input feed that sends gage cluster power into the voltage regulator in the fuel gage. Remove the stamped nut that holds the fuel gage in the housing that is also the 12v feedcoming in, use a washer, a nut and a ring terminal and tap in.

I also clipped the old needle off the old ammeter, and clipped the needle of the new volt gage short to glue the ammeter needle to it to complete the mod. I also hooked the newly modded volt gage up to a car battery charged to 13.5 volts, checked with an volt ohmmeter, and while the gsge had power running to it , i adjusted the needle where i wanted it to point to by adjusting the potentiometer on the volt gage internals to tune in the pointer

Thanks for the tips. I didn't think about trimming the center post on the housing. It appears to be completely covered by the plastic cap so no harm. I suppose the only negative might be dust getting into the cluster.

View attachment 1714955995

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Thanks to this thread, I have completed my conversion, but I want to bench test the voltmeter gauge before I reinstall the dash. Can anyone give me ideas for easy ways to do this?
 
Yep 12V car battery. Attach clip on leads to the battery and the volt gage. use a voltmeter on the battery to get its actual voltage, then you can adjust the potentiometer on the volt gage itself to fine tune move the needle to the left or right where you want it set. I adjusted my gage needle with the battery charged at 13.5V on the bench to where the needle is just a tick over half. Or slightly on the charge side of the ammeter face.
 
moparmat2000 said:
Yep 12V car battery. Attach clip on leads to the battery and the volt gage. use a voltmeter on the battery to get its actual voltage, then you can adjust the potentiometer on the volt gage itself to fine tune move the needle to the left or right where you want it set. I adjusted my gage needle with the battery charged at 13.5V on the bench to where the needle is just a tick over half. Or slightly on the charge side of the ammeter face.
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OK dumb question, but connect VM (+) to battery (+) and VM (-) to battery (-) ? When I did that the needle pegged over rapidly to the point I thought I might burn something up.
 
SteveM said:
OK dumb question, but connect VM (+) to battery (+) and VM (-) to battery (-) ? When I did that the needle pegged over rapidly to the point I thought I might burn something up.
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Gauge should have shown battery voltage. Maybe you shorted something in the mod/adapt process? Potentiometer shorted to screen? Without more info/pics, I'm guessing.
 
It shouldent do that. It should read batt voltage somethings not right. Are you sure you hooked + to + and - to - .if not it will peg the needle try reversing the leads. Or look at my pic of the conversion. The stud with the red plastic insulator / spacer i have made and installed is the positive connection.
 
Opening up an old thread but need some info. I just completed converting the amp gauge in my 73 Dart Sport to the volt meter using the Sun Pro gauge. Only problem is the gauge is not identified anywhere as to positive / negative post. Anyone done this who remembers which post is positive? would like to get it id'd before I'm ready to install it.
 
Post #135 will answer your question. Look at position of home made red plastic insulator in pic. Make sure that post doesnt short to the gage cluster housing, the negative side you can bolt right to the cluster housing using it as a ground.
 
supertruck said:
Opening up an old thread but need some info. I just completed converting the amp gauge in my 73 Dart Sport to the volt meter using the Sun Pro gauge. Only problem is the gauge is not identified anywhere as to positive / negative post. Anyone done this who remembers which post is positive? would like to get it id'd before I'm ready to install it.
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If you do hook it up backwards it should register a negative charge. Just change it back.
 
Thanks moparmat2000 and toolmanmike. Wasn't sure if hooking it up backwards would do any damage.
 
What is the IVR? Integrated voltage regulator? what are the specs or part number of the one you purchased? While looking for volt meters I've noticed new ammeters. Has anyone looked into using a higher capacity Bosch ammeter to swap out the old one?

Bosch ammeter..JPG
 
IVR is instrument voltage regulator. The gages run at 5.5 6.0 volts. Leftovers from 6v electrical systems. When it all went to 12v the car companies came up w a tungsten tipped vibrating point type regulator to bring the 12v down to 5.5-6.0 volts. As it gets old if the points stick open typically your oil press, fuel, and water temp gage drop off, if it sticks closed they peg. On dodges and chryslers its a little box w 3 prongs on it clipped to the gage circuit board. One prong is ground, ine is 12v in, the other is 6v out. Plymouths for some reason have the damn thing mounted in the fuel gage. This requires some surgery to disable the regulator while leaving the gage working.

Back then a solid state semiconductor was expensive so the vibrating points was the way to go. Now a days a NTE 960 semiconductor chip does the same job for about $1.50 plus a small capacitor as a shock absorber. For about $5 you can make one.

Forget the ammeter. The whole point of a volt conversion is to take the amp load off the bulkhead connector.
 
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