Torsion bars and lower control arm set-up

Discussion in 'Suspension, Steering and Chassis' started by SB69GTS, Jun 6, 2017.

  1. SB69GTS

    SB69GTS Well-Known Member

    Messages:
    438
    Likes Received:
    17
    Joined:
    Oct 21, 2009
    Location:
    Ontario
    Local Time:
    3:30 PM
    Hey guys, got the 1.03 torsion bars in and was wondering if someone can chime in on the adjustments. The lower control arm adjusting bolt was loosen right off .... this is a complete resto so when i rebuilt the lower control arms ...I did not tighten the torsion bar socket in them. Now I turned the bolt till it snugged up to the indent and did 6 complete turns .... before I lower the car down to the ground ..I started thinking ....should I have tightened the torsion bar socket nut first or is it ok now with the adjusting bolt for the torsion bars in 6 turns and lower the car to the ground and tighten the torsion bar socket nut. Also does any know the torque setting for the nut on the torsion bar socket in the control arm. Hope this makes sense. Its on a 69 dart with a 408 stroker, auto trans. Stock lower control arms
     
  2. 67Dart273

    67Dart273 Well-Known Member

    Messages:
    36,578
    Likes Received:
    4518
    Joined:
    Oct 14, 2010
    Location:
    Idaho
    View My Photos
    Local Time:
    1:30 PM
    Are you talking about the height adjusters or the LCA pivot nuts?

    Most guys advocate final tightening of the LCA pivots when the car is on the ground, has been "jounced" and sitting at ride height

    The adjusters about all you can do is "start somewhere" and see what you have for height. Most guys seem to want to adjust them when jacked up/ weight relieved
     
  3. 67autocross

    67autocross A new iron curtain drawn across the 49th parallel

    Messages:
    790
    Likes Received:
    258
    Joined:
    Jul 23, 2010
    Location:
    Winnipeg
    Local Time:
    3:30 PM
    Just don't adjust them up or down unless you have the car supported.
     
  4. AJ/FormS

    AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

    Messages:
    12,801
    Likes Received:
    2756
    Joined:
    Jan 19, 2014
    Location:
    Southern Manitoba,Canada, 900ftelevation
    View My Photos
    Local Time:
    3:30 PM
    The car should be on the ground ,the ride-height squared up and set, and then rolled a distance about equal to the front tire circumference to relax the suspension and tires. Every time you reset the ride-height, the car should be re-rolled.
    Then you can secure the LCA pivot pins to the K-member, with those big nuts.
     
  5. 75slant6

    75slant6 Well-Known Member

    Messages:
    4,525
    Likes Received:
    971
    Joined:
    May 15, 2011
    Location:
    Russellville, ky
    Local Time:
    3:30 PM
    Like Del and AJ said, leave the lower control arm pivot but loose until you have the ride height set, once you have the ride height where you think you want it, roll the car back and forth a few feet, it'll probably settle some, requiring you to readjust a little. Once you have rolled the car back and forth and the ride height is where you want it, torque the pivot nuts to 145 ft lb. If you torque the but before setting ride height, the LCA bushings can wear out prematurely
     
  6. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

    Messages:
    8,303
    Likes Received:
    2305
    Joined:
    Nov 28, 2008
    Location:
    NorCal
    Local Time:
    1:30 PM
    You only have to worry about doing the final torque to spec on the LCA pivot nuts at ride height if you've got the OE style rubber LCA bushings. If you have poly or delrin LCA bushings it doesn't matter at all, you can torque the LCA pivot nuts to spec at any location or setting. And note, if you're using the OE rubber LCA bushings you still want the LCA pivot nuts snug before you put the car on the ground, just don't fully torque them to spec. You don't want the LCA's flopping around when you set the ride height, so snug them up but don't tighten them. If that makes sense.

    Also, another interesting note, the OE rubber bushings are not bonded to the inner or outer shells. I'd always heard that the rubber was somehow bonded to the shells and that's what was damaged if you didn't torque the pivot nuts at ride height, but in fact the bushings and shells are just held in place by compression and friction. I took apart the bushings in the QA1 tubular arms I bought to upgrade them to Delrin before I installed them. Everything came apart smoothly in the press, you can see how the size of the bushing causes a compressive force that holds everything in place.

    QA1 tubular LCA as supplied with OE style rubber bushings. Not sure why fancy tubular LCA's come with rubber bushings, but they do. And yes, I did some TIG welding on brand new tubular LCA's to add gussets.
    IMG_3921.JPG

    LCA pin pressed out, bushing still intact
    IMG_3923.JPG

    Inner shell pressed out, you can see how the bushing has already deformed and shrunk to be smaller when the inner shell isn't forced into it
    IMG_3924.JPG

    Fully disassembled. Notice the shape of the bushing with the outer diameter now larger than the outer shell and inner diameter smaller than the inner shell, and perfectly clean shells.
    IMG_3925.JPG

    Anyway, doesn't matter, when the OE rubber bushings are fully assembled you can tear the bushing if you don't torque it at ride height because the compression and surface friction forces will keep the shells from turning and the rubber of the bushing can tear because nothing will move on the surfaces. So the procedure is the same. It's just not because anything was bonded together first.
     
    • Thanks! Thanks! x 1
    • 383Scampman

      383Scampman Well-Known Member

      Messages:
      735
      Likes Received:
      159
      Joined:
      Nov 24, 2013
      Location:
      New Hampshire
      Local Time:
      4:30 PM
      This is GREAT things to know . Next question : What and how to set ride height ? I tried to set mine according to the MOTORS Repair Book and one side was 1" higher than the other . ????
       
    • 75slant6

      75slant6 Well-Known Member

      Messages:
      4,525
      Likes Received:
      971
      Joined:
      May 15, 2011
      Location:
      Russellville, ky
      Local Time:
      3:30 PM
      Ride height is all personal preference, imo. I finally you want it set to exactly factory height, I think 72blu has a picture showing how that's done. I prefer my cars lower than ride height so I just set it to where I like the look and go with it. Mine is 25.5" from the ground to the highest part of the wheel well lip
       
    • rustycowll69

      rustycowll69 Well-Known Member

      Messages:
      1,263
      Likes Received:
      403
      Joined:
      Feb 19, 2016
      Location:
      Pacific northwest
      Local Time:
      1:30 PM
      I try to center them between the jounce and rebound bumpers. If you lower it too close to the bumper, it can put a bind on the control arm travel, it will ride like crap and you just might break something. Years ago, I bought a repo Dustpan. The PO was a huge fan of the snow plow look. It was riding on the lower control arm bumpers, and had cracked the upper control arm frame ears, among other damage.
       
      • Agree Agree x 1
      • 75slant6

        75slant6 Well-Known Member

        Messages:
        4,525
        Likes Received:
        971
        Joined:
        May 15, 2011
        Location:
        Russellville, ky
        Local Time:
        3:30 PM
        That's why I'm installing heavier TB's. Less likely to hit the bump stop
         
      • SB69GTS

        SB69GTS Well-Known Member

        Messages:
        438
        Likes Received:
        17
        Joined:
        Oct 21, 2009
        Location:
        Ontario
        Local Time:
        3:30 PM
        Thanks guys ...great info and pics. Now time to move to installing the glass and finishing the interior. 4 years of labour and might have her on the road shortly.

        20161208_113018.jpg
         
        • Like Like x 3
        • 72bluNblu

          72bluNblu FABO Gold Member FABO Gold Member

          Messages:
          8,303
          Likes Received:
          2305
          Joined:
          Nov 28, 2008
          Location:
          NorCal
          Local Time:
          1:30 PM
          Why yes, yes I do...

          factoryalignspecs.jpg

          It's straight out of the service manual. I combined a couple of pages so all the relevant info was in the same shot. That said, I would NEVER run the factory alignment specs with radial tires, they're for bias ply's. And yes, the ride height specs are completely irrelevant if you have upgraded your torsion bars. The wheel rate on a set of 1.03" torsion bars is roughly double the factory torsion bars even if you had V8 bars to begin with. So, you'll have about half as much suspension travel as the stock bars, which means you don't need to use the factory ride height specs to stay off the bumpstops.

          Alignment numbers for radial tires should come from this chart. The caster specs are on the conservative side, you can run more positive camber if you can get it.
          alignment-specifications-jpg-221767-jpg.jpg
           
        • rustycowll69

          rustycowll69 Well-Known Member

          Messages:
          1,263
          Likes Received:
          403
          Joined:
          Feb 19, 2016
          Location:
          Pacific northwest
          Local Time:
          1:30 PM
          the "factory" specs are amusing in light of the fact, when I picked up my new AAR in 1970, it was nearly riding on the LCA bumper. That's how they got the "NASCAR look" they touted in their marketing program, back in the day.
           
        • 72bluNblu

          72bluNblu FABO Gold Member FABO Gold Member

          Messages:
          8,303
          Likes Received:
          2305
          Joined:
          Nov 28, 2008
          Location:
          NorCal
          Local Time:
          1:30 PM
          That wasn't actually the factory spec though if you look at the measurements. That might have been something they did at the dealer to sell the car, or someone screwed up.

          Oddly enough, the AAR and T/A cars that were actually raced in the TransAm series were higher than the factory spec to clear the tires they were running for the competition.
           
        • rustycowll69

          rustycowll69 Well-Known Member

          Messages:
          1,263
          Likes Received:
          403
          Joined:
          Feb 19, 2016
          Location:
          Pacific northwest
          Local Time:
          1:30 PM
          nope, that was the way they came. They also had special rear springs, which contributed to the rake. I'm pretty sure the rear springs was for clearance on the side exit exhaust, which came in pieces in the trunk, because it wasn't legal in some states
          And no, the dealer never touched my car.
           
        • skep419

          skep419 It's only money, you can always make more

          Messages:
          3,044
          Likes Received:
          700
          Joined:
          Sep 18, 2008
          Location:
          Minesoooota
          View My Photos
          Local Time:
          3:30 PM
          Thanks. Went from 27” to 25.5”. 2 full turns. (Control arm bolt lossened than torqued at ride height)

          5C5831ED-E8AE-4CE6-A07E-7CA37705F564.jpeg
          AE5A0340-16A5-4014-B10A-5D8C681D412C.jpeg
          0F8B3312-0C86-46E8-8BFB-5F3689B51376.jpeg
           
          • Like Like x 5
          • rustycowll69

            rustycowll69 Well-Known Member

            Messages:
            1,263
            Likes Received:
            403
            Joined:
            Feb 19, 2016
            Location:
            Pacific northwest
            Local Time:
            1:30 PM
            it looks good to me, as long as tires clear sheet metal, you're not riding on the lower control arm bumper, and you're happy with it.
             
          • 75slant6

            75slant6 Well-Known Member

            Messages:
            4,525
            Likes Received:
            971
            Joined:
            May 15, 2011
            Location:
            Russellville, ky
            Local Time:
            3:30 PM
          • 72bluNblu

            72bluNblu FABO Gold Member FABO Gold Member

            Messages:
            8,303
            Likes Received:
            2305
            Joined:
            Nov 28, 2008
            Location:
            NorCal
            Local Time:
            1:30 PM
            Looks great! :thumbsup:

            Don’t forget that you’ll need to get a new alignment now.

            At that height you’ll also need low profile
            bump stops and larger than factory torsion bars, if you don’t have those already.
             
            • Thanks! Thanks! x 1
            • skep419

              skep419 It's only money, you can always make more

              Messages:
              3,044
              Likes Received:
              700
              Joined:
              Sep 18, 2008
              Location:
              Minesoooota
              View My Photos
              Local Time:
              3:30 PM
              Well crap its always something. Looks like I'll be calling pst for some 1.03's in the near future. Should have plenty of time being as we're suppose to get 8" of snow sunday.
               
            • 75slant6

              75slant6 Well-Known Member

              Messages:
              4,525
              Likes Received:
              971
              Joined:
              May 15, 2011
              Location:
              Russellville, ky
              Local Time:
              3:30 PM
              Bergman auto craft has 1.08” bars for $275 a set
               
            • skep419

              skep419 It's only money, you can always make more

              Messages:
              3,044
              Likes Received:
              700
              Joined:
              Sep 18, 2008
              Location:
              Minesoooota
              View My Photos
              Local Time:
              3:30 PM
              6C11E6F2-A1B9-4302-B0E1-E5CB75F25D95.jpeg
              :steering:
               
              • Like Like x 1
              • skep419

                skep419 It's only money, you can always make more

                Messages:
                3,044
                Likes Received:
                700
                Joined:
                Sep 18, 2008
                Location:
                Minesoooota
                View My Photos
                Local Time:
                3:30 PM
                47EBBC35-D071-47B8-94B2-9100FA9666C8.jpeg
                The left rear adjuster is jacked up. Cam will only turn so far. This is as good as he could get it for now.
                 
                Last edited: May 23, 2018
              • rustycowll69

                rustycowll69 Well-Known Member

                Messages:
                1,263
                Likes Received:
                403
                Joined:
                Feb 19, 2016
                Location:
                Pacific northwest
                Local Time:
                1:30 PM
                hahaha, almost 5/8" toe, before? must have been squealing the front tires on the way to the alignment shop.
                 
              • 69wacuda

                69wacuda Handling, and a 500ci engine.... All in good time! FABO Gold Member

                Messages:
                329
                Likes Received:
                30
                Joined:
                Aug 3, 2008
                Location:
                Washington
                View My Photos
                Local Time:
                1:30 PM
                I need to find a place that has printouts like this. Brings out my inner nerd, very neat.