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Projects Best Voltage drop for gauges

Discussion in 'Traditional Hot Rods' started by Sweet & Low, Dec 28, 2018.

  1. Sweet & Low
    Joined: Feb 13, 2014
    Posts: 248

    Sweet & Low
    Member

    During a conversation regarding voltage drop for the stock gauges on my 46 Ford I had mentioned that I was going to go with the C & G 3 wire unit they advertise in their catalog. I was to told that people have been having trouble with this 3 wire unit and it didn't last 3 months.

    I had taken the gauges and well as the speedometer to the Speed O shop to be checked out. The speed O needed to be rubbed on a little but all of the gauged checked out fine.

    Have any of you guy's used this 3 wire voltage drop unit with success.
     
  2. Ford used 6V gauges in their vehicles well into the '70s, get a gauge regulator for one of those.
     
  3. Also mopar, they work good and don't cost an arm and a leg. I think thi s a NAPA part number1622412-285 c
     
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  4. Bursonaw
    Joined: Jun 19, 2011
    Posts: 78

    Bursonaw
    Member

    I’ve used the runts style. So far no issues (3 years), use one for each gauge. C & G sells them as well.


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  5. 47streetrodder
    Joined: Oct 27, 2007
    Posts: 30

    47streetrodder
    Member

    I've also used the "Runtz" voltage reducers on my '47 Ford for about 3 years. Used one on each stock gauge except for the amp meter. For the amp meter, I just ran the battery charge wire through the back of the gauge from the opposite direction since I changed to Negative ground the same time I changed to 12V. I used a 65 amp alternator and the "range" of the stock gauge was just fine.

    Buy the 12 Volt conversion guide that Speedway sells. It will answer a lot of your questions that you might have regarding the ballast resistor on the coil and your other accesories. It also has a handy conversion guide for the various light bulbs.
     
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  6. Bursonaw
    Joined: Jun 19, 2011
    Posts: 78

    Bursonaw
    Member

  7. 48fordor
    Joined: Jan 16, 2009
    Posts: 137

    48fordor
    Member
    from York, PA

    LM7806 voltage regulator works great if you are comfortable with electronics. They cost less than $1.

    Sent from my SM-G960U using The H.A.M.B. mobile app
     
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  8. rudestude
    Joined: Mar 23, 2016
    Posts: 2,135

    rudestude
    Member

    Can't get much easier than these...been running them in my car for years and no problems...... 1546056252237.jpeg

    Sent from my QTASUN1 using The H.A.M.B. mobile app
     
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  9. deucemac
    Joined: Aug 31, 2008
    Posts: 988

    deucemac
    Member

    There are millions and millions of Fords running around using a stock CVR/IVR (instrument voltage regulator ) with no problem from the factory. From 1928 to 1985, Ford used a 6 volt gauge system. Except in 196 when they went to 12 volts, but installed the 6 volt gauges for 1957 and used the IVR. One regulator for all three gauges. I use a 1959 regulator because it uses spade terminals instead of the later snaps for a printed circuit board. Run the gauge power wire to one side and the other side is parallel wired to the power side of each gauge. The IVR will produce a pulsed 6 volt signal to the gauges. I have also installed later gauges when I couldn't find good original ones. Simply swap the gauge face and needle from the original gauge to the new gauge and all is well.
     
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  10. G-son
    Joined: Dec 19, 2012
    Posts: 567

    G-son
    Member
    from Sweden

    How much current does the gauges draw?
    Do you means a pulsed 12V? If you pulse 12V at 50% of the time it averages to 6V, and non-sensitive electric items will run as if they were fed a stable 6V.
     
  11. dwollam
    Joined: Oct 22, 2012
    Posts: 794

    dwollam
    Member

    I have had 2 of these Runtz from 2 different suppliers go bad on my fuel gauge. Am I doing something wrong? Yes they are grounded. Going to try a Mopar gauge voltage regulator this time.

    Dave
     
  12. deathrowdave
    Joined: May 27, 2014
    Posts: 1,823

    deathrowdave
    ALLIANCE MEMBER
    from NKy

    The Ford stuff is the answer , I have done it many times and it works as if God designed it
     
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  13. Because I had them in house when it was time. Runtz, one on each of the 3 gauges and now into 16 years of Fun they still are doing there job just fine. Being a Ford guy I also have used the stock 57 up unit on different projects but didn't have one on hand at the time. Not sure what would cause one to burn out except maybe a Power surge. High amp Alt and high R.P.M.'s maybe?
     
  14. Sweet & Low
    Joined: Feb 13, 2014
    Posts: 248

    Sweet & Low
    Member

    Thanks Much guy's for the replies. After doing a little research on the Ford Instrument regulators and how long they had been using them I'm thinking I will be at Napa on Wed.
    Man!!! you gotta love this site.
     
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  15. dwollam
    Joined: Oct 22, 2012
    Posts: 794

    dwollam
    Member

    Pist-n-Broke, it is a '58 stock 230 flathead 6 Mopar and a basic single wire gm alt in a '36 Dodge pickup. Gas gauge is the only instrument needing the voltage drop. It does still have 4:11 gears but not screaming it that hard!

    Dave
     
  16. The LM7806 regulator is the cheap and easy solution. Will work great for gas gauge, others should be mechanical and only need 12v lightbulbs.

    I run the LM7806 in my 37 Chevy Ute for many years with no problems

    Sent from my SM-J337V using The H.A.M.B. mobile app
     
  17. I see, a little Mix-n-Match going on. What can happen is even though the actual Motor isn't turning high R.P.M's Pulley size on the Crank can spin the Alt. at a high R.P.M. if not sized properly. If the Alt spins to fast the output can exceed 13 Volts. Now your Runtz has a problem. Do you have a Volt meter or Amp meter in the dash? You may need to install a larger pulley on your Alt.
    The Wizzard
     
  18. dwollam
    Joined: Oct 22, 2012
    Posts: 794

    dwollam
    Member

    Yeah, it has a stock amp gauge. It has a fair sized pulley. My Model A's run gm Alt too with very small pulleys. BTW, modern alternator systems run more like 14 volts to maintain a 12 volt battery.
    Mix and match, yep. Even has some Ford parts. The alt spacer tube is a chunk of Model A headlight bar left over from making a set of headlight mounts for a fenderless car!
    My '51 Fords and my flathead V8 cars seem to be the only cars I can keep generators working in, other than my Dodge Brothers stuff. Even my '27 T roadster has a 6 volt alternator.
    Just realized I am horning in on OP's post. Sorry.

    Dave
     
  19. I've used the stock 50s-60s ford gauge "voltage limiter" on my 41 and 48 Pontiacs and about 4 shubox fords, using original 6 volt gauges. Had great luck with all of 'em.
    Last one I bought from FoMoCo and it was $18!!!! I'm going back to NAPA for my next one.
     
  20. FWIW, the Ford style IVR that I bought from NAPA didn't work at all....
    Made in china now of course and not returnable. Found an OEM one some 40+ years old at the junkyard and works perfect. Buyer beware.
     
  21. BigChief
    Joined: Jan 14, 2003
    Posts: 2,045

    BigChief
    Member

    If your looking for NOS or junk yarding, the Ford IVR uses spade terminals on '69 and earlier Mustang/Cougar as well as F series trucks and Econolines. The snap on units were used on 1970ish and later vehicles ....the other vehicle lines probably followed suit. One will handle all of the gauges on your 46....oil, temp and fuel. The amp gauge needs to be delt with separately. Your clock will be happier with a 12v conversion and updating of the guts. As others have mentioned just swap out your gauge bulbs for 12v ones.

    Sent from my SM-G950U using The H.A.M.B. mobile app
     
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  22. Normal charging system voltage for a 12 volt system is about 13.6 volts. A fully charged 12 volt battery on its own should read 12.6 volts.


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  23. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 4,739

    Ebbsspeed
    ALLIANCE MEMBER

    The safe upper limit for a Delco 10SI is 18,000 RPM. Figure your maximum engine RPM and multiply that by the diameter of the crankshaft pulley that is driving the alternator. Divide the result by 18,000 and that is your minimum alternator pulley diameter.
    For example. assume max engine RPM is 5000, and crank pulley is 8 inch diameter, giving us a result of 40,000. Divide by 18,000 and your answer is a minimum alternator pulley diameter of 2.22 inches. Note that when you measure pulley diameters that you should measure the diameter where the belt will ride in the pulley groove, which is not necessarily the OD of the pulley. In many cases the alternator pulley will be a deep groove, which is done intentionally to keep the belt from floating out at high RPM,s.
     
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