I replaced my alternator with a 60 amp--(they didnt have a 50 amp in stock) Surprisingly-when i turn on my head lights-i see that the temp gauge quickly rises a little.... toward hot. Then as soon as i turn off my headlights-the temp lowers to the normal setting. Is this 60 amp too strong? Will i damage or cook any electronics continuing to use this alternator?
i will gladly purchase a lower amp alternator- if recommended by the Slant Six Forum.
Any feedback greatly appreciated-
HAPPY MOTORING
68 DART 270 225 3.7L

SEARCH: Alternator Wiring Upgrade>Search for all terms>Electrical

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1964 Dart GT

Sounds more like a grounding problem with the lights in the gauges to me..........

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Yes, you stand to have an electrical fire—a fast one or a slow one—unless you upgrade the charging system wiring. Yes, upgrading the charging system wiring is a bit of a nuisance, but it's worth doing even if you keep a lower-output alternator. Fact is, the charging circuit on an old Mopar is marginally adequate except on cars factory-equipped with the 60-amp or bigger alternator starting in '73; those got a much heavier-duty charging circuit. But most of our cars didn't get that.

You can do it quickly and cheaply by running two 10ga wires with ring terminals at each end directly from the alternator's output terminal to the battery + terminal. Each of these 10ga wires must have two 50A fuses, one located within inches of the alternator output terminal and the other located within inches of the battery + terminal.

Put the wires in sleeve/loom and route them where they're not likely to be snagged or cut. Across the top of the radiator support panel with anchored zip ties works well, or tucked under the lip at the top of the rad support. Once you've installed these wires your ammeter will no longer read correctly but you won't be running high current back and forth via thin wires through the firewall and low-rated ammeter, which is where the melt/burn/fire danger comes from.

Why a fuse at each end of each wire? Because that's a long run of (very) high-current cable we're running from the alternator to the battery, no matter what route we take with it. If we put a fuse only at the battery end, that's fine if a short circuit occurs somewhere downstream of the battery. If we put a fuse only at the alternator end, that's fine if a short circuit occurs somewhere downstream of the alternator. But if we want to protect against the prospect of big, destructive, costly fireworks no matter where a short circuit might occur in that line (say...like...in the middle of the line, halfway between the alternator and the battery) we put fuses at both ends.

This bypass will render your ammeter inoperative. If you want to keep the stock ammeter but without running full-car current back and forth through the firewall and the ammeter, you can install an external shunt; see here for example. This is more or less what the factory did starting in '71 on the bigger cars, and on the A-bodies for their last model year of '76.

If you want to do an ammeter-to-voltmeter conversion, Redline Gaugeworks and Williamsons can both do a stealth conversion of stock ammeter to voltmeter for "it must've come that way from the factory" appearance as seen in the '62 Plymouth shown here (look closely at the instrument panel; the Alternator gauge now has a scale from 8 to 18 volts rather than the original D at the left and C at the right—and the oil pressure gauge is another never-offered-by-Chrysler item done by one of the gauge specialty houses).

For less money (but more work) you can buy a Sunpro voltmeter, tear it apart, and mount the old ammeter face over it with good, clean results as show-and-told here.

Notes:

1. Sooner or later someone might mention an outfit called MAD Electrical. Steer clear; their methods are half-baked and in some cases technically/factually wrong.

2. If the alternator you bought is a "remanufactured" item from a parts store (in real life or on the internet) prepare for its short, unreliable life.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

As Dan explained, over current interruption (a fuse or such) is placed as close to power source feeding a given circuit. Being that an automotive 12v battery can discharge 450 to 1000 amps instently depending on its cold cranking listing to any circuit it's feeding one wants to keep that surge path as short as possible. Ditto for alternator which can only put out 60 amps in your case, but can melt any conductor in a car with ease in no time if not protected should a dead shot to ground occur.

This is how your house wiring is designed where power from pole is distributed via a service panel which contains fuses or with more modern installations circuit brakers between panel's buss bar, and various branch circuits serving the dwelling.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I can't find any 50 amp fuses to fit my 10 gauge atc in-line fuse holders. Largest I can find is 40 amps. Do I need to buy the larger 50 amp MAXI fuses and larger holders?

Dart is stock with 35 amp alternator, but it's 46 years old so I am replacing it soon and already have a new 60 amp on the shelf. Will the 40 amp fuses work, or just blow?

Alternator only puts out amperage required to operate whatever the electrical load is at any given time. In other words if only headlights are on, alternator supplies need amps to lights + whatever amps are needed to recharge battery, and needs of ignition circuit. As various devices are activated that amp flow increases.

The old 30 amp alternator supplied enough amps to operate all as built factory devices. Sometimes at idle current draw exceeded 30 amp alternator's ability to out put full 30 amps at which time battery would pick up the slack until engine rpm increased bringing alternator out put up to 30 amps. This would be an example of dimming headlights at idle, and brightening once rpms increase when under way.

60 amp alternator will act the same way, and probably be able to power full current load on it's own at idle. So as long as the theoretical load is still at or near factory original you should be OK with larger alternator. If you were to install a high draw sound system, or such wire harness will need to be up grades to carry the increased current flow (amperage).

One way to limit high current flow through bulkhead connector when using a higher than stock alternator in charging circuit ( which is the circuit most apt to be over loaded is with a bypass; see Madd below. My car has 60 amp alternator, and bypass, works fine, no melted bulkhead connections since rewiring harness in 2008.

As mention back in old text, all grounds need to be electrically good. In other words no voltage drop in ground path, and importantly also no voltage drop on + side of circuit (that would be the wires, connectors, and switches) Once voltage drop is eliminated from circuits, voltage regulator will correctly maintain voltage in harness. See Madd site for more information on charging bypass, and brighter headlights.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

hey wjajr, You mentioned Mad Electrical after SlantSixDan said someone would mention it sooner or (3 years!) later
Now I'm curious... Dan, what is wrong with MAD Electrical's methods?

Madd's charging bypass works well for Mopar harness where the charging electron flow between battery and alternator flow through directly wired amp gauge (non remote current reading type amp gauge used on later vehicles). Bypass directly connects alternator to battery bypassing and eliminating amp gauge and high charging current flow passing in and out through bulkhead connector. Bulkhead connector is a weak link to high current flow and often has built up high resistance over time from corrosion; high resistance = heat and sometimes melting. Bypass coupled with remote voltage sensing for voltage regulator allows harness to have stable voltage levels, and over charging problems are greatly reduced. But, one still needs to eliminate voltage drop through the entire system.

Amp gauge once bypassed can be replaced with a volt meter reading under dash voltage, or just left in place.

The head light relay adaptation for brighter lights is same design Dan uses. Using relays headlights are powered directly from battery and or alternator switched via relays eliminating high current flow through headlight switch and bulkhead connector and Mopar's pathetic under sized conductors. Once again, for best results, a good voltage drop free ground path has to be available to headlights.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Ah... I'm going to use Dan's two 10 gauge wire with 4 50amp fuse idea, as well as bypassing the ammeter and replace it with a sunpro voltmeter gauge and face.

There's nothing wrong with the concept, but their idea of how to fix/improve it has problems. There are better, more thoughtful ways to do it that don't cause or aggravate problems.
No, sir, it is not. The idea is the same—they identify the weakness/problem correctly—but their proposed fix addresses only about 1/3 of the problem. It takes the workload off the headlight switches, so that's fine, but it introduces unnecessary new splices (with attendant problems) and continues to use the original underspecified feed and ground wires and all the aged connections along the way: marginal when new, inadequate now it's old. That is plain and simply the wrong way to do it. If the job is worth doing (and it is), it's worth doing correctly and completely. The effort is not really any greater to do the whole job right.

It's also worthwhile to take a look at article 1 article 2 article 3 about crimping versus soldering for automotive applications.

And now I'm going away again.

-SSD

Quick Summation: Go with Dan's electrical recommendations, no need to look further. Brian

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https://tinyurl.com/yynpj4v2

I used Dan's method of two 10 gauge wires running to alt and battery + with 50amp fuses on each end. Also ran a ground loop from alternator body to ECU ground bolt, to voltage regulator ground, then to Battery neg...

Ran fine for the few times I drove it, but I noticed the battery boiling and stopped driving it.

Fast forward a few months, I forgot about the boiling battery, started and ran it for a few minutes, and boom! The battery blew a vent cap off as well as a small hole in the battery case. After cleaning all the acid off the underside of hood and fenders with baking soda and water, I replaced the battery with a fully charged new one. Even let it sit on a smart charger to top it up.

Tested 12.69 volts across the terminals, started car and measured 18.7 volts running. No wonder the battery blew.

Faulty new alternator or ???

Faulty voltage regulator.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Isn't the Voltage Regulator essentially bypassed by the direct connection from alternator to battery? Hopefully it is protecting the rest of the electrical system from power surges.

I believe the Voltage regulator is a fairly new standard motor products VR125.