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Guages Adjustment

Discussion in 'Early CJ5 and CJ6 Tech' started by mickeykelley, Jun 22, 2019.

  1. Jun 22, 2019
    mickeykelley

    mickeykelley Well-Known Member

    Republic of Texas
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    I looked in the back of the guage cluster and I don't seem to see any adjusting holes. I'd like to get a better sense on both the temp and fuel. With a 190 temp thermostats, I usually really run right at 190 so I'd like the guage to register right at the middle not above. On hot Texas summers when running a steady 45, I creep up to 200-205. On the fuel, when I show almost empty, I still have a good 3 gallons out if the 10.5. I've read about some adjusting hole where you put a jeweler's screw driver in to adjust but I just don't see it. Can anyone show a pic of it?
     
  2. Jun 22, 2019
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Why not run with the 165ºF thermostat? It was OEM.
     
  3. Jun 23, 2019
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    There's no adjustment at the gauges, AFAIK.

    I thought the standard temperature values are 160, 180 and 195F. The 195F is associated with the emissions era engines that run at a higher temp to make the combustion more efficient. With a F134, I'd think your choices would be 160 or 180F. Re the temp creeping up, the thermostat is a negative feedback system (NFS), and how close it stays to the set point depends on how much gain is in the system. A NFS can never stay exactly at the set point without infinite gain, and too much gain makes the system oscillatory (unstable). So you'd expect a small amount of variation depending on the ambient temperature and the load. If the cooling system is topping out its capacity, you'd expect temperature control to go away entirely at some point, and then coolant temp would rise in direct proportion to conditions.

    The fuel gauge is adjusted by bending the float arm at the gas tank.
     
  4. Jun 23, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    I agree with either a 160 or 180 thermostat, probably 160 would be first choice. Keep in mind your newly rebuilt engine might run a bit warmer for a while too.
     
  5. Jun 23, 2019
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    My FSM calls for the standard thermostat to operate from 165ºF to 170ºF.
     
  6. Jun 23, 2019
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    I don't doubt it. However, I looked up a '60 F134 on RockAuto (the ultimate authority) and there is no 165-170F thermostat listed. They claim a 180F is the OE part. They also list a 160, a 195 and a 205F (!) as "alternate temperatures." Right or wrong, this matches my experience when I worked parts counter. A 'stat was a generic part, and owners would experiment with engine temperature. Typically they were trying to prevent overheating by using a lower set point ... not effective. They'd ask for a cooler 'stat and we'd grab a 160F part from the shelf; didn't need to look it up.
     
  7. Jun 23, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    My FSM, new in '69, calls for a 190 thermostat. Starts to open at 180 and is fully open at 202. :shrug:
     
  8. Jun 23, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    FWIW it lists the same temp for the V-6.
     
  9. Jun 23, 2019
    mickeykelley

    mickeykelley Well-Known Member

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    I was using my memory on the 190 number, but I guess I'll have to look it up and see now. Pretty sure I got the stat from Walcks.

    I know that my modern vehicles consistently run, according to the guages, right at 200.
     
    Last edited: Jun 23, 2019
  10. Jun 23, 2019
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    They are adjustable, they have to calibrated at the factory after all...

    Depending on whether you have original or aftermarket repros there will be one or two adjustment slots but once you play with them all bets are off on accuracy, you *will* be worse off than when you started.

    For the gas gauge you'll never get it to read empty "properly", once the float bottoms on the tank there's still at least a inch of gas left.

    [​IMG]

    IMHO best off to leave them the way they are.

    H.
     
  11. Jun 23, 2019
    mickeykelley

    mickeykelley Well-Known Member

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    Yes I have the oem NOS. I've been tempted to adjust the float in the tank itself but thought it might be easier at the guage. But now you have scared me away form it, at least for now. I may play with the original I still have at some point.

    Is the worse off based on personal experience?
     
  12. Jun 23, 2019
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

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    Yes, I went through a lot of grief getting the darned things to read reasonably accurately, that was with the ones with two adjustments (maybe a King-Seely only thing)- one was for range & one for setting the lower end position & the little buggers are extremely interactive. There must have been a factory test jig & procedure but without that there's a *lot* of tweaking involved. :(
     
  13. Jun 23, 2019
    mickeykelley

    mickeykelley Well-Known Member

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    Has anyone tried to put a slight bend in the tank float for the gas issue?
     
  14. Jun 23, 2019
    mickeykelley

    mickeykelley Well-Known Member

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    I looked up receipt and yes it was a 180 thermostat from Walcks. After a drive, I've used one of those laser temp units (yes I know about them, blah, blah but it's a good quick estimate and beats the hell out of 'borrowing' the wife's kitchen unit and trying to talk my way out of that) and it has been showing 190-200.
     
  15. Jun 23, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    I've bent the float arm before, but only went for "better", not total accuracy.
     
  16. Jun 23, 2019
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

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    Howard, if you are offering this picture with the obvious screw in the middle as evidence of adjustibility, are you certain the screw does not adjust the PWM VR? That's what I would assume. This is a temperature gauge? I suspect this gauge works by the wire coil element to the right heating in response to the PWM regulated voltage. If it's bimetallic, it would bend and deflect the needle. Adjusting the cycle of the VR might change the reading, or it might release the magic smoke.
     
  17. Jun 23, 2019
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

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    Not the screw, you're correct on it's function.

    I'm referring to the area circled in gree, this adjusts (on this model) the pivot point for the gauge assembly. Again I've seen them with two adjustments.

    Either/or tricky to get right.

    upload_2019-6-23_16-0-41.png
     
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