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Gauge of Wire

Discussion in 'Truck & Equipment Repair' started by ptrkptz, Feb 27, 2009.

  1. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16

    I am sure that this has been addressed... but I have searched and have not found the answer that i am looking for...

    I have a 74 chevy pickup... the wire is the braided sleeve over the wire instead of the plastic that the newer stuff has... I have found that the wire is corroded a WAYS back... so I am looking on upgrading the wire off the back of the alt... but don't know the size as recommended w/o losing amps... this is a 63 amp alt that I am looking to upgrade and also add a dual battery system the problem is that all the high output systems have different connector, etc... I have read the forums on the dual bat setup, but looking for info on wire gauge off the back of the alt...

    Any help is greatly appreciated...
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    For a 63 amp alt 8 gage is plenty...but run it directly from the alt to the battery, do not follow the original path were it first runs of the alt to the bulkhead connector on the firewall and then down to the starter stud where the positive battery cable is located. You can leave all that stock charge wire there, just add the 8 gage from the alt directly to the battery. The shortest path is the best path.

    Make sure your ground wires/cables are also in 100% condition as well. A couple extra will never hurt.
     
  3. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16

    Gauge

    I have EVERY intention of upgrading the alternator this summer. So should i go a size bigger?? 4 Gauge??

    Also does anyone have any info on converting this stock 74 chevy alt (63 amp) to a newer HO alt... i am referring to the wiring... there is currently only the one wire coming of the stud, and then the TWO wire connection off the top of the alt. I have looked and the only thing that i have found that would be an 'EASY' swap is only about 85 amp... if i am going to upgrade i would like to at least upgrade to 100+... but those higher output alts are for newer trucks, w/ different connections...
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    You don't need to go newer to go bigger. Your '74 is equipped with a 10SI series alternator which can be had in amperage's as high as 140 amp. And you can also swap in a 12SI with no mods that can be had all the way to 200 amp and in some cases even more. All the big name alternator guys will have either series you choose to run in an amperage as high as you'd need to go.

    If you want to look around on line, check out DB Electrical, Powermaster just among a few that have high amp 10 and 12SI alternators for your application. You can even swap to a later model alt (130D CS144) if you do prefer to go that route with just a harness adapter that most of these guys can supply you with to allow the newer alt to be a true bolt on.


    Since you plans are for more alt then yes you want to upgrade all the battery cables, ground cables, and charging wire when you do. 4 gage is fine up to about 140 amp. Any more than that and you'll want to step up to 2 gage for all your cables. Be sure to run a new charge wire directly from the alt to the positive battery terminal when your doing the upgrades
     
  5. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16

    Thanks for the info B... I have asked around and I could not get a straight answer on this stuff... THANKS FOR THE HELP!!
     
  6. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16

    How do you crimp the terminals... you buy a crimping tool or you have another trick?
     
  7. SNOWPIMP

    SNOWPIMP Member
    Messages: 89

    Well I have a crimp tool but usually I just whack em with a hammer to smash them down (It's faster than digging out the tool). I like to smear antisezze on it all first too!
     
  8. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    I never crimp battery cables...always solder. Gives a better seal in the connection.
     
  9. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16

    Wiring Question

    So I started to tearing into the upgrade... :)

    And I found this (attached)... does anyone know what it is, and if so, do i have to leave it like this... or can i cut it off and just run the wires back??

    detail wiring.jpg
     
  10. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    It's just a factory splice in order to tie all the wires together vs using a second junction block or the existing one on the firewall. Thats just the way they did it back then.
     
  11. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16

    so i do need to leave it, or put that splice back in?
     
  12. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16

    If I where to replace it, where would i find something like this, especially b/c i wanted to upgrade the wiring, so the wire will be different gauges?

    Thanks again
     
  13. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    When rebuilding that section of the harness, which is basically the entire under hood battery feed/charging harness I run all the new wiring to the junction block on the firewall and use that as my connection point to tie all the wires together. Saves a splice mess is the harness that can cause later issues.
     
  14. BigDave12768

    BigDave12768 PlowSite.com Addict
    Messages: 1,446


    another fine post by SNOWPIMP this site needs more of him
     
  15. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16

    So I ALMOST finished this upgrade... question... I have upgrade the alt to 140 amp alt. I have upgraded the wire off the back of the alt that runs back to the firewall. Do I need to put a fuse in this wire somewhere?? I know from the factory... the wire was a wire that would 'melt' if too many amps. If so where do I get this from?? also how many amp "fuse" do you put in the line?
     
  16. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Did you also add the second 4 gage charging wire from the alternator directly to the battery like I previously mentioned and highly recommended?
     
  17. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16

    yep... I added the 4 gauge wire going directly from the back of the alt to the battery, but now I am just wondering about the fuse situation on the other wire from back of the alt to the firewall
     
  18. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16

    Nevermind... I found my answer elsewhere
     
  19. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Sounds good.

    Now that you basically have the system split into two paths; one wire for dedicated charging directly to the battery, and the other only to feed power to the truck, you do want a fusing means in there somewhere. I prefer to use a 50 amp inline resettable weatherproof circuit breaker. Simply place it anywhere in the feed wire between the alternator and your junction block on the firewall. A note though, this alone WILL NOT protect the trucks harness because you still have a direct connection via a stock power wire that runs from the junction block on the firewall down to the starter solenoid which is connected to the battery cable. You need to remove this wire. If you don't, you'll still have a direct (un-fused) connection back to the battery (via the starter cable) so your new inline circuit breaker will do no good. So be sure to remove that wire to allow the circuit breaker to protect the entire system.

    I'd also add a 150 amp breaker to your 4 gage charging wire between the alternator and battery for the best protection possible.
     
  20. ptrkptz

    ptrkptz Junior Member
    from Omaha
    Messages: 16

    Thanks B... once again, GREAT info!!! Keep the good work!!!