Bulkhead Instrument panel bypass.

Since I wired a 10 gauge wire from my alternator to the starter relay with a fusible link on my 64 Dart GT, is it necessary to bypass the ammeter bulkhead connectors on the instrument panel?

I wouldent think so

Take a good look at your bulkhead connector as I can never remember "what years". A "couple of years" of the early A (and B) had great big heavy feed through terminals right in the middle of the connector. They are obvious. If yours has those they will be / should be little or no trouble.

The second plan is to convert to the ‘80s-‘90s style wiring. Simply connect the alternator output stud, via some serious gauge wire (matched to your alternator’s output specs) to the battery stud on the starter relay. But be absolutely sure you splice in an appropriate length of fusible-link wire into this new conductor! Here’s what gauges to shoot for:

Alternator output rating Wire gauge Fusible Link
Under 50 Ampere 12 16
50-65 A. 10 14
85 A. 8 12
100 - 120 A. 6 10
With this done, the bulk of the charging system current will no longer flow through the firewall connector - or the ammeter. Obviously, the ammeter will no longer be accurate. The plan here is a simple accessory voltmeter, which should have its positive (+) side wired (with practically any gauge wire) to any ignition-switched 12-volt point, and the negative (-) side to ground.

As long as the ammeter never grounds out, you are fine. If it grounds to the instrument cluster or internally, you are at risk of the same issues as the charge energy flowing through it. I prefer to not have anything attached to the ammeter.

There are some voltmeters that plug into a cigarette lighter out there. Neat for someone that doesn't want an additional gauge in the car, etc. Plug it in, when you want it out, toss in glovebox, console.

I have a volt meter that is a charging port. Slightly larger than a cigar lighter socket hole. These are all over evilbay. Fill the hole in the ashtray mounting plate with one.

crackedback said:

As long as the ammeter never grounds out, you are fine. If it grounds to the instrument cluster or internally, you are at risk of the same issues as the charge energy flowing through it. I prefer to not have anything attached to the ammeter.

There are some voltmeters that plug into a cigarette lighter out there. Neat for someone that doesn't want an additional gauge in the car, etc. Plug it in, when you want it out, toss in glovebox, console.

Click to expand...

So, if I decide to disconnect the ammeter, should I just cut off the ends and tape them up? Also, now if I wanted to hook up lets say a stereo, I would not be able to use the ammeter studs for a power point, or add an accessory fuse panel from that point. I am just trying to decide what would be the best thing to do. Since I purchased the car, I have had trouble keeping the positive wire through the bulkhead connected. I have taken the bulkhead apart three times over the past 11 years to tighten up the female connector for the positive wire.

You have to hook the two wires from your ammeter together. I use a machine screw, nylock nut, elec tape/shrink tube.

cchrishefish said:

Also, now if I wanted to hook up lets say a stereo, I would not be able to use the ammeter studs for a power point, or add an accessory fuse panel from that point. ......................... I have taken the bulkhead apart three times over the past 11 years to tighten up the female connector for the positive wire.

Click to expand...

You are fighting yourself. Adding power accessories to the ammeter is what helps tear it up, and adds to the damage done to the bulkhead connector.

Many people condemn the MAD article but you should AT LEAST READ IT because it gives a great overview and why and how this system is so bad in modern times.

here..........

Catalog

And on that page is a great simplified diagram of the primary power distrobution



This diagram is a great map of the main failure points, just follow the "road." The fuse link can fail..........the bulkhead connector terminals (any of them, but especially the big red and big black)...........the ammeter wire terminals can fail, the ammeter itself can fail.......and RARE but there has been about a dozen cases I'm aware of that the WELDED SPLICE has failed

Now "in theory" everything should be "run" by the alternator, BUT IT DOESN'T happen that way, because 'back in the day' many of those alternators SAGGED at night, at low speed, at idle. So you are sitting there at a light, wherever, at idle, with the headlights on, your foot on the brake, the radio/ stereo on, the wipers on, the heater on. Now current is coming back through from the "battery side" through all of that to the welded splice. And the battery is discharging. Then you leave the light you are driving along. Now the alternator comes back up, current goes from the alternator (functionally not electron flow) through the black bulkhead terminal, to the welded splice to accessories. And through the ammeter, back out through the red ammeter wire and bulkhead to the battery.

40-50 years later, maybe someone added a "great big" alternator, corrosion, moisture, ........and......................................

JMO... the mopar charging system has NO perfect spot to pull power for accessories. With the bulkhead and ammeter in the mix, you have to choose alternator or battery side.

My way of deciding, if the item will run primarily when the engine is running, alternator side. When you have things like fans/stereos they can be on when the engine is off, where do you pull power.

Any instructions that have a comment that you want to attach power at battery, so you have "full battery power", the writer has no idea how an automotive electrical system works.

The Mad article is great for how things work, not a fan of the fix/approach.

Another issue with the actual ammeter itself.......and this depends on the model year........is the construction of the ammeter and WHERE IT MOUNTS. If you read the MAD article notice, there is a photo of a melted ammeter. I'm well acquainted with that mental picture, having see a few pickup ammeters that looked exactly like that .......from winches, "big" off road lamps, or snow plow hoists

In some years, the ammeter is mounted--------always by the studs------through the wall of the cluster casting WHICH CAN BE PLASTIC. If heat from current causes anything to be "loose" then the heat gets worse, the "loose" gets worse and a great big snowball effect (fireball effect?) happens.

Also, on some ammeters, THE STUDS ARE NOT FASTENED really, and act sort of like "bolts". So any looseness in the assembly, allows a loose connection between the stud(s) and the meter shunt---the guts of the meter. Another self destruct situation.

Now I LIKE ammeters, but the only way they can really be implemented in large current installations is WITH AN EXTERNAL SHUNT. This allows shorter, larger wiring, with good, solid terminations, and NO spade/ flag/ push on terminals such as in the bulkhead connector.

Here is how I ran mine in schematic #1. Schematic #2 shows bypassing the bulkhead altogether. If your connections at the connector are clean and tight I dont feel theres a need to bypass it and drill holes in your firewall.

Thank you for the tips. My 64 Dart GT is charging very well now, I jumped from 12.6 volts to around 14 volts. I replace the alternator last week from Advance Auto Parts. The alternator they provided me fried my brand new votage regulator. When I took their alternator back to the store for testing, it kept tripping the testing machines circuit breaker. They pulled 3 more alternators off the shelf including additional ones at other local stores. All of their alternators failed. I was able to get a good one at Pep Boys and another new solid state voltage regulator on Ebay. The next time I replace the alternator, I am going to get a 1972 version because I read in an article that it is more reliable.

Don't just "get a 72." You need to make sure it's a SQUAREBACK, and not a ROUNDBACK. The newer squareback was the improvement. "The thing is" rebuilders cannot be trusted

ALWAYS check the field circuit continuity before hooking up. MANY rebuilds come with at least one--and sometimes both--brushes grounded.

If you are using the 69/ earlier VR you can use either an earlier or a later isolated field alternator.......simply ground one field connector