Certified speedometer

General Mopar Tech Discussions

  1. peabodyracin

    peabodyracin FBBO Gold Member FBBO Gold Member

    Messages:
    381
    Likes Received:
    301
    Joined:
    Jul 10, 2015
    Location:
    Minnesota
    Local Time:
    8:54 AM
    Is this unit one that would have come from a police car? I've not seen this before. For some reason I always thought certified speedos just had more gradients between the digits.

    SANY0001.JPG
     
  2. 1967coronet

    1967coronet FBBO Gold Member FBBO Gold Member

    Messages:
    1,330
    Likes Received:
    1581
    Joined:
    Jun 19, 2014
    Location:
    Iowa
    Local Time:
    8:54 AM
    Yes , police , sheriff , state troop, ect .
    Some plain jane state cars or locals would have them also, fire marshal, ect.
     
    • Agree Agree x 6
    • PurpleBeeper

      PurpleBeeper Well-Known Member

      Messages:
      4,528
      Likes Received:
      3286
      Joined:
      Mar 20, 2011
      Location:
      Chicago
      Local Time:
      8:54 AM
      Yep agree with 1967.
       
      • Agree Agree x 2
      • peabodyracin

        peabodyracin FBBO Gold Member FBBO Gold Member

        Messages:
        381
        Likes Received:
        301
        Joined:
        Jul 10, 2015
        Location:
        Minnesota
        Local Time:
        8:54 AM
        Thanks much!
         
      • YY1

        YY1 Well-Known Member

        Messages:
        15,237
        Likes Received:
        7364
        Joined:
        Jun 26, 2010
        Location:
        FL
        Local Time:
        9:54 AM
        They are "certified" to be accurate within a certain spec.
         
        • Agree Agree x 2
        • rolling_Thunder

          rolling_Thunder Well-Known Member

          Messages:
          652
          Likes Received:
          163
          Joined:
          Jul 19, 2008
          Location:
          Los Angeles, CA
          Local Time:
          6:54 AM
          A lot of corporate fleets cars were equipped with them - mostly Law enforcement

          The certifying process is basically putting it on a dyno and getting the vehicle to predetermines speeds (ie. 15mph, 30mph, 60mph) and verifying the speedo reads within a certain percentage variance. I had to do that on the police vehicles we serviced back when.
           
          • Like Like x 1
          • Bluenoser

            Bluenoser New Member

            Messages:
            4
            Likes Received:
            1
            Joined:
            Feb 19, 2018
            Location:
            B.C.
            Local Time:
            6:54 AM
            I agree with all the other posters as to which cars had certified speedos. I used to do dealership PDI's on police vehicles. Each car with the certified speedo would have a paper in the glove box stating what the actual speed was and what the speedo showed. E.G the speedo might show 60 MPH when the actual speed was maybe 61 or 59 MPH or whatever. This was shown for all speeds from about 20 MPH to max Mph on the speedo. A speedo could be out by 1 MPH at 60 and be out by 3 MPH at 90. Hence the Certified Speedo.
             
          • peabodyracin

            peabodyracin FBBO Gold Member FBBO Gold Member

            Messages:
            381
            Likes Received:
            301
            Joined:
            Jul 10, 2015
            Location:
            Minnesota
            Local Time:
            8:54 AM
            Thanks again to all for your input. Kind of a neat piece!
             
          • machphil

            machphil Member

            Messages:
            22
            Likes Received:
            2
            Joined:
            Sep 23, 2012
            Location:
            Illinois
            Local Time:
            8:54 AM
            I had a '64 Dodge 330 Ex Illinois State Police car in '71. It had that certified speedometer. It was to provide law enforcement with a speedometer that could provide a degree of accuracy for reporting on police reports. Was it effective. I don't know. However, I later had a '77 TBird and while browsing a salvage yard up around Beloit, Wi I found a '79 LTD II that was a former police car and had the Certified speedometer in it. Since my T Bird was equipped with an 85 mph speedometer I pulled the Certified speedo from the '79 LTD II and installed it in the T Bird. The LTD speedo was calibrated and marked for speeds up to 140.
             
          • Slap Stick

            Slap Stick FBBO Gold Member FBBO Gold Member

            Messages:
            2,439
            Likes Received:
            2581
            Joined:
            Jan 15, 2017
            Location:
            Missouri
            Local Time:
            8:54 AM
            Thing is that speedymeter was calibrated for a certain rear gear and tire size. It may have been on the money or way off after the swap.
             
          • peabodyracin

            peabodyracin FBBO Gold Member FBBO Gold Member

            Messages:
            381
            Likes Received:
            301
            Joined:
            Jul 10, 2015
            Location:
            Minnesota
            Local Time:
            8:54 AM
            But it says CERTIFIED. Shouldn't that be good enough? You're right of course. I am just intrigued by it, having not seen one before for that vintage.
             
          • James L. Coster

            James L. Coster Member

            Messages:
            5
            Likes Received:
            0
            Joined:
            Jan 29, 2020
            Location:
            Pittsburgh, PA
            Local Time:
            9:54 AM
            i practiced criminal defense law for some 28 years in Pittsburgh, PA and often did a lot of "speeding citation" cases. most citations state the driver was exceeding the speed limit by 10 miles per hour or more. on some occasions, usually in small towns, a driver would be charged with exceeding the posted speed limit by "5 mph." in those cases, i would often argue that the average auto manufacturer speedometer can vary 3-7 miles per hour over the actual speed of the vehicle and thus, a driver cited for driving "5 miles per hour" over the posted limit could not be found guilty if he testified that he was "going the posted speed limit" according to the speedometer in his car. in some cases, i brought in articles from various test facilities showing the OEM speedometer deviations. most judges would accept that defense. this "lawyer trick" was happening all over the State so the Pennsylvania Legislature added a statute to the motor vehicle code that provided that if a driver was charged with driving "5 miles per hour over the posted speed limit", a plea of guilty would not result in any points being assessed against the driver's license. in Pennsylvania, it is relatively easy to accumulate enough "points" to have your license suspended for a period of time. that statute ended the "factory speedometer" defense in a lot of my cases as after the statute was passed, i could usually get the policeman to just change the citation to "driving 5 miles per hour over posted speed limit" and the driver would plead guilty, pay the $300.00 fine and court costs and walk out of the courtroom. the drivers were happy, the State of Pennsylvania was happy collecting more fines, and i was happy because i walked out with a decent fee just for "negotiating the deal."
             
          • peabodyracin

            peabodyracin FBBO Gold Member FBBO Gold Member

            Messages:
            381
            Likes Received:
            301
            Joined:
            Jul 10, 2015
            Location:
            Minnesota
            Local Time:
            8:54 AM
            Interesting, and welcome to the forum!

            The times I got ticketed (many years ago) were for 'exhibition of speed'. In those situations I found it ironic that others appearing for speeding tickets recorded at a speed appreciably higher than I'd been tagged for, got out with much lower fines. Often the offender would have an attorney with them and they'd even negotiate the fine lower. When my turn would come, the judges seemed to like throwing the book at me because of the title of my offense. I vividly recall the court room gasping when my fine was announced. Painful lesson to learn on a service man's pay at the time.
             
          • DeltaV

            DeltaV When you have to shoot, shoot, don't talk! FBBO Gold Member

            Messages:
            7,879
            Likes Received:
            20513
            Joined:
            Jul 11, 2015
            Location:
            Savannah, GA.
            Local Time:
            9:54 AM
            Pics below are from my small "stash" of parts. The Mopar box label is copyright dated "1972" and the certified speedo (and calibration slip) must be from 6-74 (see box label).

            IMG_20200202_114921753.jpg
            IMG_20200131_192805088.jpg IMG_20200131_192648586.jpg

            BTW, this Mopar p/n 3592927 certified speedo is a perfect fit/replacement for the 85 mph speedo that came in the '79 300 cars (Cordoba SS22L9R).
            --------------
            Edited 02-02-2020 to correct errors.
             
            Last edited: Feb 2, 2020
            • Thanks! Thanks! x 1
            • rarefish

              rarefish Well-Known Member

              Messages:
              342
              Likes Received:
              147
              Joined:
              Jul 9, 2013
              Location:
              NY
              Local Time:
              9:54 AM
              Here is a certified speedometer that I took out of a 1964 Savoy Police car that I found in a junkyard several years ago.

              102_5980.JPG
               
              Last edited: Feb 4, 2020
              • Like Like x 1
              1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
                By continuing to use this site, you are consenting to our use of cookies.