Can't get dwell high enough...

Electrical and Ignition

  1. TylerW

    TylerW Well-Known Member

    Messages:
    974
    Likes Received:
    74
    Joined:
    Feb 29, 2008
    Location:
    Elkton, TN
    Local Time:
    7:01 PM
    Hello again:

    I am dealing with an unusual issue on a common '67 single-point distributor. I cannot get the distributor to come into spec regard dwell and point gap. Point gap spec out of the FSM is .014-.019 and dwell angle is supposed to be 28-32 degrees. Both of these are very common specs.

    At .017 point gap I have about 11 degrees of dwell. I closed the point gap up to .014 and that increased the dwell to 15 degrees. At this rate the point will nearly be closed up before I can get the dwell where the book specs it and that's nowhere near normal. That's asking for a set of burned points IMHO.

    This is annoying, because I went to much effort to set up the points with the distributor out on the bench. The distributor shaft is nice and tight with thrust within spec. it has not been rebuilt. The points are new old replacement stock Mopar points(in the old green box), the rotor is NORS Mopar and the cap is NORS Standard...for what it's worth.

    How does it run? Well it runs good most of the time. The only time it doesn't run good is when I lean on the secondaries hard for a while, then it starts to miss. It also breaks up when you have it in neutral and hold the engine at about 3K....so, something's not right.

    So...what is the general consensus when the specs won't jibe? Wear somewhere in the distributor? I did double-check my readings with two different "period-correct" dwell meters I have and they both agreed. Thanks for any advice.
     
  2. toolmanmike

    toolmanmike FABO Staff Staff Member FABO Gold Member

    Messages:
    43,674
    Likes Received:
    26984
    Joined:
    Jan 18, 2006
    Location:
    Iowa
    Local Time:
    7:01 PM
    I bet your distributor cam is worn. The rubbing blocks do need a little grease.
     
    • Agree Agree x 4
    • RustyRatRod

      RustyRatRod 30 Degrees Outta Whack FABO Gold Member

      Messages:
      56,309
      Likes Received:
      25213
      Joined:
      Jun 7, 2010
      Location:
      Georgia
      Local Time:
      8:01 PM
      What are we workin on here, a briggs and stratton?
       
      • Like Like x 1
      • Agree Agree x 1
      • Demonic

        Demonic Well-Known Member

        Messages:
        589
        Likes Received:
        349
        Joined:
        Mar 21, 2015
        Location:
        Maryland
        Local Time:
        8:01 PM
        Yup. Time to go electronic.
         
      • 1969383S

        1969383S FABO Gold Member FABO Gold Member

        Messages:
        4,830
        Likes Received:
        1992
        Joined:
        Jan 8, 2012
        Location:
        Cumming, GA.
        Local Time:
        8:01 PM
        And or the shaft bushing is slap wore out! Or your dwell meter is just flat out lying to you!
         
      • rustycowll69

        rustycowll69 Well-Known Member

        Messages:
        1,955
        Likes Received:
        841
        Joined:
        Feb 19, 2016
        Location:
        Pacific northwest
        Local Time:
        5:01 PM
        is the dwell tach set to the correct number of cylinders?
         
      • yellow rose

        yellow rose Doctor of Thinkology.

        Messages:
        18,812
        Likes Received:
        14910
        Joined:
        Jun 19, 2015
        Location:
        Living on the razors edge
        Local Time:
        5:01 PM

        Ok, define slap. I just need to know what scale slap correlates too.

        Thanks In Advance.

        YR
         
        • Agree Agree x 1
        • halifaxhops

          halifaxhops It's going to get stupid around here! FABO Gold Member

          Messages:
          54,505
          Likes Received:
          22325
          Joined:
          Jan 20, 2014
          Location:
          CENTRURAL, PA
          Local Time:
          8:01 PM
          You guys hit it one of three things the cam plate is worn and smaller than it should be, ditrib bushings can be worn and also the top of the distrib shaft can also be bent, You will see that cranking the engine it will wobble.
           
        • halifaxhops

          halifaxhops It's going to get stupid around here! FABO Gold Member

          Messages:
          54,505
          Likes Received:
          22325
          Joined:
          Jan 20, 2014
          Location:
          CENTRURAL, PA
          Local Time:
          8:01 PM
          anything over .003 play side to side they are done.
           
          • Thanks! Thanks! x 1
          • yellow rose

            yellow rose Doctor of Thinkology.

            Messages:
            18,812
            Likes Received:
            14910
            Joined:
            Jun 19, 2015
            Location:
            Living on the razors edge
            Local Time:
            5:01 PM

            Thank you. I'll add that to my limited but quite spicy vernacular.
             
          • halifaxhops

            halifaxhops It's going to get stupid around here! FABO Gold Member

            Messages:
            54,505
            Likes Received:
            22325
            Joined:
            Jan 20, 2014
            Location:
            CENTRURAL, PA
            Local Time:
            8:01 PM
            :rofl::rofl::rofl:
             
          • RustyRatRod

            RustyRatRod 30 Degrees Outta Whack FABO Gold Member

            Messages:
            56,309
            Likes Received:
            25213
            Joined:
            Jun 7, 2010
            Location:
            Georgia
            Local Time:
            8:01 PM
            "Slap" means moreso than normal. Like Brenda has some good stuff, but Trixie can slap suck a golf ball through a garden hose. See how that works?
             
            • Like Like x 2
            • Thanks! Thanks! x 1
            • RustyRatRod

              RustyRatRod 30 Degrees Outta Whack FABO Gold Member

              Messages:
              56,309
              Likes Received:
              25213
              Joined:
              Jun 7, 2010
              Location:
              Georgia
              Local Time:
              8:01 PM
              Why is that? A points ignition can operate every bit as good as electronic as long as everything is right and adjusted properly.
               
              • Agree Agree x 3
              • j par

                j par Well-hung Member

                Messages:
                17,928
                Likes Received:
                8776
                Joined:
                Jul 2, 2014
                Location:
                Portland Oregon
                Local Time:
                5:01 PM
                Redneck adjectives...
                 
              • RustyRatRod

                RustyRatRod 30 Degrees Outta Whack FABO Gold Member

                Messages:
                56,309
                Likes Received:
                25213
                Joined:
                Jun 7, 2010
                Location:
                Georgia
                Local Time:
                8:01 PM
                It's an adverb, since in this example, it's describing the verb "worn" as in worn out.
                 
                • Like Like x 2
                • Thanks! Thanks! x 1
                • j par

                  j par Well-hung Member

                  Messages:
                  17,928
                  Likes Received:
                  8776
                  Joined:
                  Jul 2, 2014
                  Location:
                  Portland Oregon
                  Local Time:
                  5:01 PM
                  You're probably correct I just got my first cup of coffee yet still 5 in the morning..
                  at any rate this is exactly why I have all my customers just put in electrical module in there. It's almost 2020, at this day and age filing points and reading dwel meters is ridiculous... Not one of my customers likes paying for the electronic conversion but all of them loved the idea of one less thing to worry about more..
                  Edit; the last one was a 65 Ford Mustang and it fired right up and he loved it...
                   
                • Demonracer

                  Demonracer 71 Demon 00 Ram 16 Chrysler 300S 05 Caravan FABO Gold Member

                  Messages:
                  2,269
                  Likes Received:
                  432
                  Joined:
                  Jan 31, 2010
                  Location:
                  Cleveland, Texas
                  Local Time:
                  7:01 PM
                  Points distributor, maintenance. Electronic, no maintenance set it & forget it.
                   
                  • Agree Agree x 1
                  • RustyRatRod

                    RustyRatRod 30 Degrees Outta Whack FABO Gold Member

                    Messages:
                    56,309
                    Likes Received:
                    25213
                    Joined:
                    Jun 7, 2010
                    Location:
                    Georgia
                    Local Time:
                    8:01 PM
                    I don't disagree at all, but it's what he has now. It's almost always cheaper and easier to fix what you already have than to convert to something else.
                     
                  • AJ/FormS

                    AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s FABO Gold Member

                    Messages:
                    16,883
                    Likes Received:
                    5447
                    Joined:
                    Jan 19, 2014
                    Location:
                    South-Central Manitoba,Canada, 900ftelevation
                    Local Time:
                    7:01 PM
                    I'm gonna guess the Dwell meter is on wrong scale, or the rubbing block is too short, or the corners of the breaker cam are really really worn off, or your feeler gauge is in metric,lol. Of these, the meter is the most likely.
                    Here's how you prove the D is ok ;
                    Firstly vertical thrust on Mopar Ds pretty much doesn't matter. But side play, as mentioned, sure does.
                    So just set the points to whatever, just get a number. Then check the pointgap on every lobe; it should be the same. Then pick a lobe any lobe, and measure the gap with the lobe pushed as far away from the rubbing block as it will go, and then pull the lobe as close to the rubbing block as possible and remeasure the gap. As you have discovered, there is a direct correlation between the pointgap and the dwell, with the variation being something like 1* per thou change in gap. So that's why .003 side play takes you from one side of the spec to the other. But worse is that this varying pointgap plays havoc on cylinder to cylinder timing.
                    I'm gonna guess that your D will be close enough to run, cuz I still think it's your meter.(or feeler gauge lol)
                    So reset the gap to the wideside of the spec and call it done. Then go borrow a second dwell meter and recheck the dwell, with it set to the proper number of cylinders. If it still acts gooffy, I would check the alternator output looking for an A/C component and fix that; it ain't supposed to be there; one or more of the diodes is leaking.If it still acts goofie,I would suggest to replace the condenser. If it still acts gooffy IDK.

                    If this is a slanty; I feel your frustration.
                    If a slanty in an old combine, with the D on the backside. I think I'd rather go dig a latrine
                     
                  • TylerW

                    TylerW Well-Known Member

                    Messages:
                    974
                    Likes Received:
                    74
                    Joined:
                    Feb 29, 2008
                    Location:
                    Elkton, TN
                    Local Time:
                    7:01 PM
                    Thanks for the help so far. I'll try to address the questions for clarification:

                    1. It's not a Briggs. It's a 383. I purposely keep some details out of the question so that the replies are not unduly influenced.

                    2. The dwell meter is on the right scale. Both of them. That's too easy of an answer.

                    3. Living in the south, I understand "slap", along with pretty near, about liked to and won't stay cranked...lol.

                    4. I had 4 different distributors to choose from. Two were original un-rebuilt units and two were remans, which I don't ever use. All of the distributors, with the exception of one original unit, had negligible side to side shaft movement. I selected what I thought was the best unit to clean and use. I suspect that the worn cam lobe is a possibility. I'll look at it again.

                    5. I agree that points "can" work as well as electronic. My slant runs just fine with points. However, you constantly have wear going on with points which leads to something like what I am going through.

                    Thanks again.
                     
                  1. This site uses cookies to help personalize 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.