stock gage output wire 67 barracuda engine harness

[moparmat2000]

Hi Y'all,

I am looking at my year one repop engine harness alternator output wire. It looks to be 10 gage to me. I am going to wire out the amp gage setup that goes thru the bulkhead so i will be running this lead directly to the starter relay lug with a fuse link.

According to some different websites including i believe painless wiring show a 14 gage fusible link with a 10 gage alternator output lead. And this diameter wire to be sufficient for 50A to 65A output alternators.

I am going to run a mini denso 50 amp alternator. So my question is, what is the stock gage alternator output wire in this harness for a 67 b cuda. Simply because i am sure the repop harness is made to stock specifications. If its a 10 gage great, if its a 12 gage thats ok, as well the websites i visited stated 12 gage is good max up to 50 amp but requires a 16 gage fuse link.

Anyone know the true gage of this wire.
Please let me know
Matt

 

[67Dart273]

Frankly, I'd upgrade it to at least no8. (10 ga in the "house" world is a 30A circuit) If you are going to run a "one wire" you need even larger, no6. this is because a "one wire" senses voltage right at the alternator

 

[moparmat2000]

Yes its a 1 wire Alt. Im sure you know what your talking about housewise, however houses are typically 110V plus amperage. Guys are typically running 6 ga wire with 100 amp alternators. This is 50.

 

[67Dart273]

You have to understand the reason on a "1 wire." It's because the sense point is IN the alternator so the charging wire becomes MUCH more important, because voltage drop on the charge wire will allow the battery / system voltage to sag, meanwhile the regulator "thinks" things are just fine.

If you can find the chart Delco put out, "one wire" setups require MUCH larger charging wire than do external VR systems.

 

[67Dart273]

Yes its a 1 wire Alt. Im sure you know what your talking about housewise, however houses are typically 110V plus amperage. Guys are typically running 6 ga wire with 100 amp alternators. This is 50.

You missed my point. a 10 ga wire in a house circuit is fused for only 30A, something like the water heater

 

[67Dart273]

Here is the chart I was thinking of. Notice that 50A up to 4 ft is right on the dividing line to 8GA. This "4 ft" is "round trip" meaning you must also consider the GROUND return

http://delcoremy.com/Documents/Troubleshooting/Delco-Remy-Charging-Cable-Flyer-8-14.aspx

 

[moparmat2000]

I cant edit my title, what i meant was alternator output wire thickness. Stock harness 67 b cuda

 

[moparmat2000]

Here is the chart I was thinking of. Notice that 50A up to 4 ft is right on the dividing line to 8GA. This "4 ft" is "round trip" meaning you must also consider the GROUND return

http://delcoremy.com/Documents/Troubleshooting/Delco-Remy-Charging-Cable-Flyer-8-14.aspx

Ok understood, however isnt the ground, a case ground from the alternator to the engine?

 

[67Dart273]

Well you have to consider the entire length and there IS some drop. In a factory car the path would be alternator.........engine block........to battery cable........to battery NEG.

In that case there might not be much drop, but there will be SOME. This is why, when a chart "hits" the borderline, you always fudge to the larger size.

Also, if you still have the stock wiring in through the bulkhead, ammeter, and back out, that is probably more than the 4 ft in the chart. Alternator......around through the bulkhead.......through the ammeter.....back out the bulkhead.....fuse link......starter relay........and finally to battery POS

The other thing you wanna consider is "modern times." If you are (I am) running EFI, a big stereo amp, or some other electronic devices, you really want better regulation that we had "back then."

Let's take a "stocker," in the winter, idling parked with the lights, wipers running. You stopped to pick someone up. The old 35A alternator lets system voltage sag clear down to 12.6 OR BELOW. Then when you get to tootin' down the road, you are up there at 14.2 and in some cases MORE

I like to compare this to house voltage. If your house voltage changed from 120 to 140V you would think something was gonna blow up, and it just might!!! The same percentage of chage applies from 12--14V

 

[moparmat2000]

Well i got a 50A alt within 4 to 7 foot length of wire. Chart shows that to be 8 gage. 50 amp is at the lower end in that block 65A is at the higher end.

Block ground, then heavy battery to engine block ground cable.

 

[67Dart273]

That's it!!

 

[moparmat2000]

Thanks 67dart273

I snap shotted your chart onto my phone. I got to unwrap part of the new harness to mod it anyways. No big deal going a bit further down the line to run an 8 gage wire to the alternator. I will prob run this lead along with its fusible link directly to the battery positive terminal.

Btw i just got my mini denso 50A in the mail yesterday. Dang, if that aint the cutest lil alternator i have ever seen LOL.

Thanks 4 your help
Matt

 

[moparmat2000]

67dart273, You prev asked about the wiring going thru the bulkhead and the ammeter connection.

I am not running the alternator output wire thru the bulkhead. Its going to be run with the other wiring in the harness but will loop around right to the positive battery terminal. Prob around 7 ft including a fusible link. I will be going w the 8 gage, and a 12 gage fusible link.

I converted the ammeter to a volt meter, and attached the 2 ammeter wires together and stuck it back in the harness. The black wire in the engine side of the bulkhead that the ammeter used to feed i put a repop fusible link on, just like the one on the red feed wire that goes into the bulkhead from the starter relay and feeds the other side of the ammeter this wire with the additional fuse link runs now as a red 10 gage wire back to the starter relay. In other words the starter relay now has 2 red 10 gage feed wires going to the bulkhead and attaching where the red and black ammeter/alternator wires attached. These both have fusible links. My alternator output wire goes straight to the battery.

Heres another question. I have 3 ft of fusible link wire. I planned on crimping and soldering a ring terminal to the fusible link to attach at the battery post. How long should i make the fusible link wire before attaching it to my 8 gage output wire.

I am assuming the shorter the fusible link the faster it will blow if over loaded, the longer it is the more overloading it can take before it blows. I may be wrong with this, but if i am right, is there a chart or a formula to figure out fusible link length for application.

Thanks
Matt

 

[67Dart273]

I think you want them "shorter the better." They operate I believe more like an undersized piece of wire, that is the longer the wire, the more voltage drop, IE the more power they must dissipate.

Chart? Sorry. Maybe contact whoever manufactured them.

I reworked my own car with a Jeep fuse/ relay / power center, actually TWO of them (one parted out) and melded together so to speak. What you are looking at here is the prelim mockup in my 67. I have replaced the driver side vent box with a very very cut down Mustang vent, leaving only enough for the damper butterfly. The EZ/ Painless panel is up in the "stock" location, the Jeep box in the middle, and the Holley EFI computer at bottom. Believe it or not a kick panel will fit over it

Anyhow, "I digress." The main fuse will simply be a couple of parallel of those "big" fuses into that panel. It is fed with no4 starter cable coming from a bulkhead feed-through where the battery cable goes out the firewall.

 

[moparmat2000]

Everywhere i have looked online all they say is fuse link needs to be 4 sizes smaller than the wire it protects, and never more than 9 inches long.

This is all the consistent info i have found on this subject. I guess i will make the first link at 6" long and see how it goes.