How To: Upgrading Wiring and Alternator

[HawkRod]

So if I understand you your 8 ga wire that runs from the battery in the trunk to the distribution block on the firewall does not have a fusible link? Although a stock car does not have a fusible link from battery to distribution block, I would put one in near the battery as protection in this circuit. Why? Well this wire goes a long distance through lots of turns and potential sharp edges. If it ever gets pinched, insulation wears off, etc, you will have a fusible link to protect you from a fire. Certainly not mandatory, but I would if it were my car.

You don't need a fusible link between the distribution block and the alternator. The stock alternator will work fine with 12 ga wire. If you upgrade your alternator, you should upgrade the wire but no fusible link is used in between - the alternator can't power 800 amps and weld metal...

As far as where to run the wire to the solenoid. Check out the picture below - I don't have a recent picture from my car so this is before it was restored. There is some incorrect wiring but this picture will serve its purpose. See the yellow and red wires on the distribution block? The wire just above that with the square basket to hold the wire is the mount for the starter solenoid.

 

[krowbar]

Yes that is how I have it wired now to the alternator. The original starter relay that you pictured. I have to tie into that wire back to the trunk mounted relay? Or do I just take that one off and go from that stud ( original relay ) to the trunk mounted relay with a New wire.

 

[HawkRod]

Yes that is how I have it wired now to the alternator. The original starter relay that you pictured. I have to tie into that wire back to the trunk mounted relay? Or do I just take that one off and go from that stud ( original relay ) to the trunk mounted relay with a New wire.

The distribution block is already a relay. See the yellow wire in the picture? This is the start wire from the ignition key, and this is a low power wire. The big fat red wire in this picture next to it is where the start signal from the yellow wire gets grounded. For my 4 speed, it is grounded by a safety switch to make sure the clutch is depressed before you start the car. In an automatic, it makes sure the tranny is in Park or Neutral. In this picture, someone bypassed that and ran a big fat red wire straight to ground (this means my starter would turn anytime the key was placed in the start position, regardless of clutch position). The result of the yellow wire completing a circuit is how the distribution block relay gets tripped and it then puts 12 volts on the starter solenoid.

From a power and safety perspective, you could run a second wire from the yellow wire connection point to your relay in the trunk. The problem with that scenario is that your trunk relay wouldn't have the same interlocks (like a clutch) to trigger it. More than likely, your relay coil in the trunk goes straight to ground. So the choice then is to come off your starter relay wire.

What I would do is take a second, 14 or 16 ga wire off of the same lug that powers the starter relay (the "square one" above the yellow/red). However, I might suggest an inline fuse (not fusible link) in this wire near the source. Run this wire to the trunk to power your trunk relay coil. Then your relay in the trunk will trigger with the same interlocks as your distribution relay.

To make sure we are not missing anything in our conversation, see if you can sketch up your circuit and post it. This way, we can be sure neither one of us is misunderstanding the other.

Good luck,

Hawk

 

[krowbar]

Thanks, I think I understand. I will try to post a sketch this evening.

 

[krowbar]

The orange highlighted wire is the one I plan on running for the one we discussed earlier. I need a relay and fuse for the fuel pump and probably a 10amp fuse for the MSD box. Am I on the right track?

 

[HawkRod]

the orange highlighted wire is the one i plan on running for the one we discussed earlier. Am i on the right track?

OK, so several comments:
1) The orange highlighted wire will do fine to power your solenoid. If it were me, I would add an in-line fuse where the red rectangle is located to protect this line since it does go a long distance. While it will work without it, I think this is cheap insurance. Note that in your current picture you have no fused protection for that wire. In the start position, the battery terminal (where my blue line #3 goes) is connected to this line. This goes straight back to the battery with no protection.

2) So speaking of no protection. I would add a fusible link at my green circle. No, stock cars do not have a fusible link between the battery and starter solenoid, but again, this wire is traveling a long distance. This is cheap insurance, in my opinion.

3) I am assuming that you still have a fusible link that goes where my blue line is located from this point to your bulkhead connector. This wire ultimately goes to the ammeter gauge in the dash.

4) Putting a fusible link where I indicated the yellow triangle is not common, and I see no reason to add one here. It certainly won't hurt anything, but I doubt your alternator would be able to melt it anyway due to a short.

I am confused by a couple of things in your drawing. I assume that your new 12 volt distribution block electrically ties all the lines together that you have shown. If my assumption in #3 is correct, your ammeter gauge will no longer work. The ammeter gauge measures current flowing either in from point 3 (discharging) or from the original charge wire (charging). Since you are also connecting the charge lug of the alternator to the distribution block, current can charge the battery without going through the ammeter gauge.

The other thing I am confused about is the drawing of the original starter relay. Mine has 4 connections, not 5.

I need a relay and fuse for the fuel pump and probably a 10amp fuse for the msd box. Am i on the right track?

I would agree with this.

 

[krowbar]

#3 comment is correct. I use all aftermarket gauges w/ voltmeter so I hardly ever look at the amp gauge anyway. The original starter relay --I wasn't sure of the exact location of the connections. ( at work now ). What size fuse for the orange highlighted wire is recommended? MSD says a 30 amp for their box will work. The fuel pump rates @ 4 amps full draw so I figure a 30 amp relay and 5-10 amp fuse for that. I will work a fusible link in the #2 location you noted. Thank you very much for helping me with this. Ken.

 

[HawkRod]

What size fuse for the orange highlighted wire is recommended?

This wire should only be powering the coil of your relay. Probably a 1A fuse will be fine.

MSD says a 30 amp for their box will work. The fuel pump rates @ 4 amps full draw so I figure a 30 amp relay and 5-10 amp fuse for that.

My MSD instructions (MSD-6A) state that it draws 0.9A per 1000 RPM. Sounds to me like a 10A fuse should be fine. Of course, you may want to check other references - I am not sure where you got your 30A number from - but if this recommendation comes from MSD for your box, then so be it. It just sounds high to me...

For the fuel pump, yeah, a 5A fuse sounds right - 10A if you have access to nothing else.

Thank you very much for helping me with this. Ken.

You are very welcome. Good luck with it!

 

[micmoe]

Thanks loads hsorman, I'm beginning to rewire my 66 Belvedere with a harness from Speedway parts but this sheds some more light on what to upgrade under the hood. But I stll have one question; Did you replace any terminal ends on the wires in the Firewall Terminal Block? and if so Where did you get them? This would seem to be the quickest method to rewiring or just eliminate the Firewall Block.

Micmoe

 

[HawkRod]

Thanks loads hsorman, I'm beginning to rewire my 66 Belvedere with a harness from Speedway parts but this sheds some more light on what to upgrade under the hood. But I stll have one question; Did you replace any terminal ends on the wires in the Firewall Terminal Block? and if so Where did you get them? This would seem to be the quickest method to rewiring or just eliminate the Firewall Block.

Micmoe

Hi Micmoe,

In my case, I did not replace any terminal ends on my wiring harness. For my car, I purchased all new wiring to ensure all my wiring worked well and that I did not have any issues with old, cracked wires. I wanted to keep the car as stock looking as possible, and also to make any mods I made as easily reversible as possible.

A very common modification is to disconnect the terminals and drill out the alternator and battery wire connections and just run a straight wire through the firewall. This allows for the use of heavier gauge wire and it eliminates the weak point of the terminals. The method I used is inferior to this, but since I split the load, I am still not exceeding factory power (I am also not drawing tons of extra power either).

Hope this helps.

Hawk

 

[dink]

Just replace all of the wires and connection... Ron Francis has the best retrofit out there.... Then use relays on all Tue switches to reduce switch load... And then you're basically where I'm at in the wires... Also I use tinned marine wire when I can and heat shrink soddered connection...

 

[Nacho-RT74]

Won't post what I have told since... ever about this. Lot of ppl knows it, and is pretty much similar to 72RoadrunnerGTX has made, but sure I need to tell one thing.

when you understand what the ammeter gauge is, how works and what means its reading, You'l be CLEAR on everything and sure about your what car requirements and mods, for REAL.

THAT'S the first step.

Lot of "upgrades" or mods made on our cars wiring are really unnecesary and that's because ppl doesn't understand this. More based on fear than kwoledgement.

 

[HawkRod]

Won't post what I have told since... ever about this. Lot of ppl knows it, and is pretty much similar to 72RoadrunnerGTX has made, but sure I need to tell one thing.

when you understand what the ammeter gauge is, how works and what means its reading, You'l be CLEAR on everything and sure about your what car requirements and mods, for REAL.

THAT'S the first step.

Lot of "upgrades" or mods made on our cars wiring are really unnecesary and that's because ppl doesn't understand this. More based on fear than kwoledgement.

So Nacho, thanks for the post but may I request that you add some details. The purpose of this thread is to help people understand and upgrade their wiring systems. If you have something to add, please do so, but be specific so someone reading this can understand what you are telling them to do and why.

Thanks

 

[Nacho-RT74]

sorry! I thought pasted the link!

http://www.dodgecharger.com/forum/index.php/topic,33574.0/all.html