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308--replacement "power distribution block"?

Discussion in 'Technical Q&A' started by greg328, Jun 27, 2005.

  1. greg328

    greg328 F1 Rookie

    Nov 17, 2003
    4,133
    Austin, TX USA
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    Greg
    Can anybody recommend a new, better "power distribution block" to replace the old stock one? I hear Bussman and Monster Cable make them, just don't know which one may be best suited to my 1977 308 GTB.

    Greg
     
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  3. WaltP

    WaltP Formula 3

    Nov 1, 2003
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    Walt P
    Birdman on this board makes one for a very reasonable price, check the archives.
     
  4. greg328

    greg328 F1 Rookie

    Nov 17, 2003
    4,133
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    Greg
    I'm not talking about the fuse blocks. I'm talking about the little white plastic box below the relays that houses the power distribution block..

    I already use Birdman's fuse box--love it!!


    Greg
     
  5. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    May 4, 2001
    31,348
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    That was one of the first things my mechanic got rid of
     
  6. greg328

    greg328 F1 Rookie

    Nov 17, 2003
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    Greg
    Tommy,
    What did he put in place of it?

    Greg
     
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  8. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    May 4, 2001
    31,348
    Birmingham, AL
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    Tommy
    Honestly I do not know. One evening it was running like total****. I somehow got it over to his shop and when we went to check the fuel pump relay we found that coupler was as hot as a firecracker. He told me something about these and Fiats. (Fiats used to be his thing). He fixed them together somehow but it is so wrapped up I'll have to ask him because I can't see what he did. Whatever it was worked because this was back in 98 and about 30,000 miles ago. It solved the problem I was having, that's for sure.
     
  9. greg328

    greg328 F1 Rookie

    Nov 17, 2003
    4,133
    Austin, TX USA
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    Greg
    So it's also called a "coupler"? I guess that makes sense. It joins 4 wires..

    OK, I just pulled mine out. All 4 spade connectors looked fine. I've got the white plastic rectangle in my hand now, and it looks fine. It only seems to be a plastic receptacle, 3 inches X 1 inch, that houses 2 male connectors in the center, providing 4 tips-2 per side- to the female connectors.

    First, does anybody know which wire goes to what? The order/color is:
    left side upper: double white wire,
    left side lower: red,
    right side upper: red,
    right side lower: red w/ a black sleeve. All wires are heavy gauge.

    This thing looks fine. I see no evidence of worn/rotted connectors. Yet, I'd like to replace it w/ something more robust, if anybody can recommend something...

    As most of you may know, I'm trying to figure out the cause of my "G" light woes, glowing under seemingly light load (brake light circuit, blinker circuit, etc.....), also evidenced by my newly installed voltmeter showing 10-12 volts......

    Greg
     
  10. tatcat

    tatcat F1 Veteran
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    Sep 3, 2001
    8,367
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    rick c
    good luck greg.if you can dope this out you may go down in the fchat annals as a god. you could be the go to guy for electrics. the thought of this stuff sends me into convulsions. crazy things happen to me. i was driving yesterday and the wipers started working all by themselves. i turned the switch on and then off and they stopped and were ok today. why? who knows. maybe you greg. i've been plagued by electrical problems since i owned my first TR3.
     
  11. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    May 4, 2001
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    Tommy
    I guess that's not the problem. When mine crapped out it was screwing with the fuel pump. The white plastic part had brown "hot spots" all over it too from overheating. You should PM rifledriver about this. He will know.
     
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  13. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    May 4, 2001
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    Tommy
    I just remembered another thing. About a month after I got my 308 (Fall 97) the "G" light (solid red light in my QV) lit up and stayed on right after I washed the car. I ran it back to the same guy. The brushes on the regulator were worn out. He put a new one on and that solved that problem too. The alt has never been out of my car since I have had it.
    I never understood why it came on right after I washed it though since it was the brushes that were bad, not a water problem.
     
  14. greg328

    greg328 F1 Rookie

    Nov 17, 2003
    4,133
    Austin, TX USA
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    Greg
    Tatcat,
    Believe me, I'm flying blind! I'm just exploring all my options, as I discover them on this fantastic website...

    My "power distribution block" looks fine, but I probably need to test it for resistance, to be sure.....

    Any Monster or Bussman alternatives, anybody???????

    Tommy,
    My alternator was rebuilt last month, including a new voltage regulator.
    I need to check out my electrical system, but just have been swamped with work (a great thing when you're in the music business!!) I would be really shocked if my battery or alternator were at fault, as they are both new...
    Greg
     
  15. greg328

    greg328 F1 Rookie

    Nov 17, 2003
    4,133
    Austin, TX USA
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    Greg
    bump..........
     
  16. Verell

    Verell F1 Veteran
    Consultant Owner

    May 5, 2001
    7,000
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    Verell Boaen
    I think you're looking in the wrong place. To the best of my admittedly ageing memory, the power coupler has never come up as an issue in Fchat or Flist.

    Unless there are signs of overheating, It's probably adequate.

    However, I'm sure that a pair of the smaller monster power blocks could be made to work, just have to figure out how to insulate them. Or you could just get some neutral bar from an electrical supply place & figure out how to mount it.
     
  17. Gianluca

    Gianluca Formula Junior

    May 6, 2003
    349
    Centreville, Virgini
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    Gianluca Chegai
    Mine was overheated really baddly from a bad spade connector.
    I made a bus strip out of brass to accomodate the natural lay of the wires.

    Since my memory is very similar to Verell's (but just a bit worse) I do not remember how I insulated them. Probably with a bunch of electrical tape. I do remember thinking to adapt a pill box or something like that but I do not think I ever done it.

    This bus was extremely easy to make.
     
  18. greg328

    greg328 F1 Rookie

    Nov 17, 2003
    4,133
    Austin, TX USA
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    Greg
    You're right, that part tested fine. I put it back.

    Took some measurements today w/ my multimeter, and determined that my big voltage draw occurs when I turn on the A/C. I recently installed (not personally!) a modern A/C compressor, a rotary Sanden, to improve cooling.
    This thing really pulls the system down; I can hear the engine lug, which of course is normal to a certain extent, and the whole electrical system becomes "overtaxed". My voltage readings drop to 10 volts or so, both on my VDO voltmeter on the dash, and testing fuse readings.

    Brake lights and blinkers also pull the readings down about 1.5 volts (from a healthy 13.6 volts with no accessories on). What do you think--bad voltage regulator? I just had the alternator rebuilt, to 75 amps, and a new voltage regulator. New battery also (Optima red-top)
     
  19. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
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    Paul
    These cars produce very little charging current at idle, so when the AC kicks in, the motor drops revs, the electrical load jumps, and with an already reduced Alt. output, your voltage would drop down fast even with a good battery. Lower voltage requires higher amperage, which causes higher resistance. Only cure is to increase engine speed, or change the pulley size to drive the Alt. faster. But then you will over rev the Alt. at high engine speeds.
     
  20. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    May 4, 2001
    31,348
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    My repaired connection is insulated with lots electrical tape. It has done well for 7 years now
     
  21. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
    6,687
    North shore, MA
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    THE Birdman
    Greg,
    When you turn on the AC, does the voltage drop at the battery or only at the fusebox? If it drops at the battery, the battery is bad. You either have a bad battery or a bad connection someplace between the AC and the battery. The current requirements of the AC clutch should not drop the voltage at the fusebox enough to worry about.

    Remove and clean the big cables on the battery, and also clean the ground cable where it attaches to the frame. Work your way backwards with the voltmeter until you find the issue.

    I personally would try swapping out the battery first.

    Birdman
     
  22. greg328

    greg328 F1 Rookie

    Nov 17, 2003
    4,133
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    Greg
    Thanks, Birdman. I was hoping you'd chime in on this. Also, see my other post "New voltmeter reveals big problems!" Along the same lines.....

    I need to measure at the battery w/ A/C on. I haven't done that yet. You're saying that if it drops to 10 v or so, then it's bad? Is that because a good battery should never drop below 12 v? It shows ~12.5 v with engine off....

    More ideas, please!! I'm pumped about solving this without having to pay my mechanic!!!!!


    Greg
     
  23. Birdman

    Birdman F1 Veteran

    Jun 20, 2003
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    Greg,
    Just go one step at a time. You need to find out if the battery is the issue first. Then work your way methodically along the electrical system.

    Birdman
     
  24. greg328

    greg328 F1 Rookie

    Nov 17, 2003
    4,133
    Austin, TX USA
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    Greg
    Birdman,
    For sure I will check battery cables, and clean the ground.
    But, my battery shows ~12.5 V cold, engine off....

    Doesn't that mean it's OK?

    Greg
     
  25. Jdubbya

    Jdubbya Two Time F1 World Champ
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    Dec 28, 2003
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    John
    Drive the car down to where you bought the battery and have them load test it!! It may read fine cold with the car off but may not be fine under load! Start with the easiest and cheapest fix first. If it's bad ( yes, many people have had bad, brand new batteries- myself included) you should be able to get it replaced free! Can't get any easier or cheaper than that!!
     
  26. Verell

    Verell F1 Veteran
    Consultant Owner

    May 5, 2001
    7,000
    Groton, MA
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    Please stop creating new threads related to this problem.

    Having 2 threads for this problem is too confusing. Easy for members to miss info/advice/results posted in the other thread. (Actually I think it's more like 3 or 4 threads if you go back a few weeks.)

    Put yourself in the place of a future researcher who's trying to solve the same problem. He'll go nuts trying to figure out the time sequencing between the threads.

    As to the specific question, yes, a bad battery with high internal resistance, or a bad cell can measure 12.5V when disconnected (ie: cold & engine off) & the voltage drop way down under load.

    To facilitate this, I"m copying the last couple of posts from the voltmeter thread here:


     
  27. greg328

    greg328 F1 Rookie

    Nov 17, 2003
    4,133
    Austin, TX USA
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    Greg
    Sorry, my bad. I created this post related to a question about my "Power distribution block", under the relays. In hopes of finding the cause of my low voltage situation. The other thread was also created for the same purpose, referring to my VDO voltmeter readings.....

    Sorry.....!

    I still welcome more ideas....I'll be taking some more measurements later today and tomorrow....


    Greg
     
  28. greg328

    greg328 F1 Rookie

    Nov 17, 2003
    4,133
    Austin, TX USA
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    Greg
    OK, I took some more battery voltage measurements:

    Again, cold, engine off, 12.36 Volts.

    Engine running, no accessories, 14.06 Volts (after alternator kicks in)

    Engine running, wipers and blinkers on, 14.06 volts..

    Engine running, A/C turned on, 12.5 volts, and engine lugs way down...!

    I'm trying to pull the power lead on the A/C clutch to isolate the problem, but I can't get to it! Somebody said you can pull it off from the top....

    By the way, the right-side front fan runs with A/C on; that's normal, right?

    Greg


    PS--Haven't taken any measurements at A/C compressor/clutch, alternator or starter solenoid. My rear left is up on a jack stand awaiting a repaired shock, so I can't lift the rear right.....
     

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