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Technical 6 volt gauges/12 volt system

Discussion in 'The Hokey Ass Message Board' started by 66panel, Apr 20, 2014.

  1. 66panel
    Joined: Jan 1, 2012
    Posts: 39

    66panel
    Member

    I've spent several hours searching, found tons of info but nothing specific to my issue.
    working on a 50 f1, 302/c4. Installed an ir1 regulator to get 6v to the gauges then grounded the sender wires at each sender-all 3 gauges moved full scale. Replaced the oil sender with echlin op6091, temp sender with echlin ts6464 (correct replacement for the original) and purchased a new fuel sender.
    The oil pres. ga moved up about a 1/2 in. then dropped back down. The temp ga seems to be functioning ok but the needle starts from the hot side and moves towards the cold side. The fuel sender moves about a 1/2 in. Grounding the sender circuits still moves the gauges full scale. Vehicle is grounded well, battery to motor, motor to frame and to body.
    There must be something obvious I'm missing, I just don't see it. Any suggestions? Thanks in advance.
     
  2. Leviman
    Joined: Dec 11, 2012
    Posts: 201

    Leviman
    Member

    Wouldn't that truck be a 6v positive ground? I have a 55 Ford car radio and it's 6v positive ground. That would explain at least the temp gauge.
     
  3. 66panel
    Joined: Jan 1, 2012
    Posts: 39

    66panel
    Member

    I thought about that but all the info I found says it doesn't matter. The needle is at the high side even at rest (key off).
     
  4. Do you still have the copper tabs connecting each gauge to the next one? I used Runtz reducers on mine, removed the copper tabs then wired the gauges in sequence. Everything works fine.
     

  5. 66panel
    Joined: Jan 1, 2012
    Posts: 39

    66panel
    Member

    Thanks GreenMonster48. Yes, the straps from ga. to ga. are there. Using the cvr, it's wired just as ford did it in later years. It should work. I'll go back out today with a fresh mind and take another look. thanks for the link, good info.
     
  6. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,406

    Flat Ernie
    Tech Editor

    You shouldn't have changed the senders. The IR1 (which I don't like, but it does work) reduces your voltage and is all you need. If you want to try to change all your senders, you don't need the IR1. Trying to match modern 12V senders to original KS gauges is challenging at best, but it can be done.
     
  7. JeffB2
    Joined: Dec 18, 2006
    Posts: 8,826

    JeffB2
    Member
    from Phoenix,AZ

  8. The temp gauge will always go to hot with the key off. Normal.
    The King-Seely fuel gauge does not seem to work correctly with any sender except the stock one. I had to find an OE sender to get my fuel gauge to work right.
    If you use the stock senders and the correct amount of voltage, they should work.
    Still not super accurate tho...
     
  9. 66panel
    Joined: Jan 1, 2012
    Posts: 39

    66panel
    Member

    Thanks for the replies fellas. The reasoning behind replacing the senders was to have new parts in place, he's working towards daily driver status. The temp sender is the correct replacement for the original, the fuel sender is a reproduction and the oil sender is a common ford sender (good replacement for original I don't know but seems to be commonly used in this situation). The correct replacement oil sender apparently no longer available. I'm getting the same results with new/old senders, what I haven't figured out is why if I ground the sender circuits with direct ground, the gauges will go full scale. Using either fuel sender hooked up to that grnd the gauge will only come up just about 1/2 in. (manually moving the sender). I've checked resistance of both fuel senders they do seem to match, but I don't have an analog meter. The digital jumps around so much it's difficult to get accurate readings. I 'm not breaking new ground here, this should work. At this point I'm considering installing newer gauges in the original housing. Maybe using 80-86 f series gauges. Thanks again for the help.
     
  10. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,406

    Flat Ernie
    Tech Editor

    The original KS senders don't use variable resistance, so measuring their resistance proves almost nothing except they're not "open".

    6V conversion (I prefer CVR vs IR1 choppers or Runtz resistors), original senders, done.
     
  11. 66panel
    Joined: Jan 1, 2012
    Posts: 39

    66panel
    Member

    So getting a resistance reading says the sender isn't open, yet the gauge doesn't respond. How do ks senders operate? There has to be some sort of variable signal to move the gauge. Yes/no? I get the same result at the gauge with either sender. I hope I don't sound argumentative, just trying figure out what I don't know that's keeping me from figuring this out.
     
  12. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,406

    Flat Ernie
    Tech Editor

    The King Sealy senders used a heated bi-metallic strip to open/close a set of contacts multiple times sending a full 6V to the gauge in intervals. The gauge also has a bi-metallic strips which heats and bends and moves the needle via a gear train.

    It's all about a total current through the gauge to cause enough heat to move the needle the appropriate amount. The KS senders use a full 6V intermittently and a variable resistance reduce the voltage to lower the current. It CAN be done with variable resistance senders, but they're not always accurate...
     
  13. 66panel
    Joined: Jan 1, 2012
    Posts: 39

    66panel
    Member

    Thanks Flat Ernie. Got a clearer picture of what's going on.
     
  14. 66panel
    Joined: Jan 1, 2012
    Posts: 39

    66panel
    Member

    Fired it up to move it and the fuel ga. started working. Seems some what accurate. He's gonna drive it for a while and see what happens. He still likes the idea of later gauges in the original housing. To be continued....
     
  15. If you have a gauge that is reading backward swap the wires fro one side to the other. For your oil sender just use the stock oil sender it is not volt specific all it does is creat resistence until it reaches full ground.

    99.9% of the time if a functional guage doesn't read properly it is the fault of the sender. The sender has to supply the proper OHM value for the guage to reads properly. Again resistence is not volt specific, it is resistence not voltage that your guage is measuring.
     
  16. 66panel
    Joined: Jan 1, 2012
    Posts: 39

    66panel
    Member

    Thanks porknbeaner. RMR&C tells me the temp ga. does start from the hot side. So I'm good there. As far as the oil pres. sender, haven't found a direct replacement, at least through napa. If anyone has a source for original let me know. Thanks.
     
  17. Autozone now has vintage parts in their computer system. They had to do this because anyone born after 1990 can't read a book.


    Go the zone and tell the counter guy to look in the vintage parts. I have actually found brake parts for 40 fords in their system.

    Another trick I do, I know it probably isn't kosher is to not daisy chain my gauges especially when I am changing voltage. I run a seperat power source to each gauge. You can still run them off of a single resister but use a separate wire for power to each gauge. I will not look factory but if you don't let anyone under your dash it will be fine. it works for me.
     
  18. 66panel
    Joined: Jan 1, 2012
    Posts: 39

    66panel
    Member

    Right on . I'll try auto zone and see what they come up with. If I can get the right sender I'll separate the power feeds to each gauge and see how it works. Thanks man.
     
  19. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,406

    Flat Ernie
    Tech Editor

    The temp sender in early Fords works backwards. No juice, it reads full hot, key on it goes cold.

    The senders in the early Fords do not use variable resistance. That said, you can replicate the chopper action of the original KS senders with a variable resistance gauge with some very careful trial and error. The action of the gauge serves as a built-in dampening effect, so go slowly when evaluating different resistance senders...
     
  20. Stock F-1 oil pressure senders are available through any early Ford supplier.....Mac's, Dennis Carpenter, etc. I have several extra used ones if you wanna try a different one.
    I ended up using a mechanical gauge in my F-1 because the OE one was not very accurate.
     
  21. deucemac
    Joined: Aug 31, 2008
    Posts: 1,136

    deucemac
    Member

    The Ford gauges work just as Ernie said.They deflect based on the amount of heat in the bi-metal spring. Henry figured out that the gauge will last longer if less heat is usually run through it so the highest heat will be at a point on the gauge you don't want to see normally i.e. oil pressure very low/ high heat in normal range and up the lower the heat. The temp gauge full hot is the most heat on the gauge so that if you are running normal there is low heat on the spring. Same with the fuel gauge, If you were like me in H.S. I NEVER had enough money for a full tank and full on the gas gauge is the high heat point. In my case the fuel gauge would have lasted darn near forever! One side bonus for the fuel gauge is that because it works by heating a bi-metal spring, it does not heat or cool quickly, and that gives it a great dampening on the gauge to nullify reading changes from driving along a rough road and fuel splashing in the tank. My SW gauges drove me nuts without a baffled tank and add a bouncing sender and a magnetic gauge, it would bounce all over the place!
     

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