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'65 Daytona, Pinion Angle "Broken Back" configuration???

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  • #16
    Ok, I spent some more time with the measurements. To insure consistency I made sure I was using a common side of the angle gauge - regardless of the contortions it took to read it.

    I got 8 degrees on the machined end of the output shaft.

    I got 4 degrees on the driveshaft.

    I got 0 (zero) degrees on the pinion yoke (using a long socket on the cap seats).

    So if I do the math (that I still struggle to grasp) I get:

    Output shaft 8 minus driveshaft 4 = 4 degrees

    Pinion yoke 0 (zero) plus driveshaft 4 = 4 Degrees

    For the moment (I'll get to it eventually) I won't sweat the 1/2 degree. I just feel content to be ... that close for now.

    Thank you all for your patience (WCP especially). Hopefully I'm moving forward. I've done all kinds of swaps, rebuilds etc., but this is the first time that I have ever had to deal with driveshafts and pinion angles. I've done two other transmission swaps and the original driveshaft just fit right in. Not this time. Still I'm happy I found an appropriate length shaft with the correct trans yoke and correct rear U-joint for $20!

    Tom
    '64 Lark Type, powered by '85 Corvette L-98 (carburetor), 700R4, - CASO to the Max.

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    • #17
      Again...
      The 'plane' that the crankshaft is whatever it is.
      The angle that the driveshaft is at in relation to the crankshaft is what counts.
      If that angle is, say 4 degree's, then the angle between the pinion shaft 'plane' should be -4 degree's in relation to the driveshaft.
      Whatever you have in front you take out in back. It should be as close to zero as possible.
      You could stand the car in it's nose and that relationship would not change.
      You do want the suspension at ride height, so jacking the side of the car up and measuring things from the side is kind of futile.
      You can jack the rear of the car up, and put the rear axle on jackstands and measure it with the front wheels on the ground.
      The crankshaft angle to driveshaft and the driveshaft angle to pinion angle will be the same as if it was on all fours.
      It is not rocket science.
      The reason for needing some angle is to oscillate the u-joint rollers in the caps and on the trunnions, or you will brinnel the rollers into the cap and trunnion and have a short u-joint life.
      Big differences in u-joint angle 'differences front to rear' will cause vibrations.
      The same rules apply for side to side.
      These specs are almost always from the driveline people (Spicer/Dana, etc) and not from the vehicle manufacturer.
      Studebaker bought from vendors and relied on their recommendations and engineering expertise.
      HTIH (Hope The Info Helps)

      Jeff


      Get your facts first, and then you can distort them as much as you please. Mark Twain



      Note: SDC# 070190 (and earlier...)

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      • #18
        IIRC, it was a lot less than 11 degree's.. More like 4 or 5 degree's....or less.
        And 'out of phase' is the rotational position of the trunnion position on the driveshaft tube, front to rear.
        I don't think he cut and rewelded his driveshaft tube, and most driveline shops would not have a clue to the original Stude OE spec for that any more.
        IIRC, there was an oscillation frequency issue that was solved by a shift in the phase of the u-joints in relation to each other.
        A cheap band-aid cure for a harmonic issue, which occasionally plagues vehicle manufacturers (think Lark convertible weights by the front end).
        Solutions have to be cheap per unit....

        Originally posted by WCP View Post
        Wittsend, what you observed is the way Studebaker built them - right or wrong. Also if you remove the driveshaft, and eyeball the universal joints, you will find that they are out of phase by some 11-13 degrees, as I recall. Apparently they had their reasons for that setup.
        HTIH (Hope The Info Helps)

        Jeff


        Get your facts first, and then you can distort them as much as you please. Mark Twain



        Note: SDC# 070190 (and earlier...)

        Comment


        • #19
          "you will find that they are out of phase by some 11-13 degrees," / "and most driveline shops would not have a clue to the original Stude OE spec for that any more."

          Apparently few if any. A 100 link per page Google search of "Studebaker drive shaft phase rotation"... and this post is the only relevant thing that showed up.

          No, I have not applied the phase rotation to the Buick shaft. Strange that other cars run the same configuration and don't use it. Is it because of the broken back configuration??? I don't see it mentioned in the other cars that run a "broken back." This is a hobby car that will see a few hundred miles a year unless something is blatantly disruptive I'll live with it.
          '64 Lark Type, powered by '85 Corvette L-98 (carburetor), 700R4, - CASO to the Max.

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          • #20
            Hi Tom.
            I have been away for a couple of days.
            What you have measured is about where it should be. The 1/2deg probably won't matter. Test drive the car and see if the tailshaft vibrates. You can tell if the 1/2deg is of any concequence by gas on gas off at 60mph. If there is any vibration with gas on (diff wind up) shim the rear engine mounts up a little bit. that will lessen the front angle and increase the rear angle.
            good luck
            Allan
            Allan Tyler Melbourne Australia

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            • #21
              I have a lark with a chevy V8 and I was able to get the engine to about 4 degrees down and set the diff at 4 and a little more up. As others have said the angle of the shaft is completely irrelevant. I have no idea if the broke back configuration will work without the yoke offset but manufactures have all gone to the more conventional arrangement for a reason I presume. As long as you are fabbing things up I'd get conventional angles on it.

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              • #22
                Hi Tom
                I checked my tailshaft today and it has no offset on the yolks. As I said earlier I forgot all about it when I had the shaft made. On my Hawk it does not appear to make any difference.
                Allan
                Allan Tyler Melbourne Australia

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                • #23
                  Allan - Thanks for checking. At this point I think I'll just go forward with my setup (which is what Junior told me to do all along) and see what I have.

                  rickhmn2 - That minimum I was able to get the transmission was 7 degrees down. Even at that the transmission was within 1/4" of the tunnel. BTW, the 7 degrees was relevant to the frame rail being at 0 (zero).

                  My assumption is that Studebaker ('65 Lark type in my case) went with the "broken back" because the car has about the shallowest driveshaft tunnel I have ever seen. If both the the transmission and the differential point downward the driveshaft can be lower.

                  ...

                  It has been an interesting journey with this subject. Some adhere to the more conventional angle down (trans) / angle up (differential) of equal angles. The end result being the transmission and differential centerlines are parallel. With the minimum of 7 degrees down on the transmission I was able to achieve I'm not too sure this is viable - at least on this particular car. My understanding is 1-3 degress is desirable.

                  While one could do the math and get the right measurement (regardless of the cars inclination) having a zero reference is helpful to the novice. This method also rules out the angle of the driveshaft as relevant.

                  ...

                  At least as I understand it with the broken back configuration the driveshaft angle does factor in. I was getting what I thought were strange numbers (T=8, DS=4, Dif=0) until I factored all three.

                  ...

                  The U-joint offset is a mystery to me. I understand about harmonics, but it would seen a compromise at best. Other manufactures don't resort to this method with similar set ups. Studebaker owners have stated to have had driveshafts made up without the offset and without issue.

                  Again, thank you to EVERYONE for your help. It was greatly appreciated.

                  Tom
                  '64 Lark Type, powered by '85 Corvette L-98 (carburetor), 700R4, - CASO to the Max.

                  Comment


                  • #24
                    The non-constant velocity behavior of a pair of u-joints occurs at twice shaft speed, so it cancels out the same whether the transmission and pinion shafts are parallel or in the "broken back" configuration. The angle between the pinion shaft and driveshaft, and between the transmission main shaft and driveshaft must still be close to equal.

                    Comment


                    • #25
                      This video, while drag race oriented, gives you an idea of how the pinion angle changes under accelleration/decelleration....

                      http://www.flickr.com/photos/simpkinsfamily/7387713670/
                      HTIH (Hope The Info Helps)

                      Jeff


                      Get your facts first, and then you can distort them as much as you please. Mark Twain



                      Note: SDC# 070190 (and earlier...)

                      Comment


                      • #26
                        Cool video Jeff. Just about straight at the rear yoke under acceleration. I would imagine the spaghetti noodle springs on my lark twist my rear end up even higher.
                        Jamie McLeod
                        Hope Mills, NC

                        1963 Lark "Ugly Betty"
                        1958 Commander "Christine"
                        1964 Wagonaire "Louise"
                        1955 Commander Sedan
                        1964 Champ
                        1960 Lark

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                        • #27
                          On my 66 Daytona it bothered me that the fan was so close to the radiator at the bottom & how the engine sat low in the rear. When I replaced the 283 overdrive with a 327 4 speed I shimmed up the trans mount as high as I could but still had the low condition. I too used a junk yard driveshaft (from a Chevelle if I remember right) & thought it would work good being it was thicker than what was in the car originally. When all was said & done I drove it fine. No vibrations or issues. I'm sure the driveshaft isnt out of phase like the original but I'm not gonna worry about it.
                          59 Lark wagon, now V-8, H.D. auto!
                          60 Lark convertible V-8 auto
                          61 Champ 1/2 ton 4 speed
                          62 Champ 3/4 ton 5 speed o/drive
                          62 Champ 3/4 ton auto
                          62 Daytona convertible V-8 4 speed & 62 Cruiser, auto.
                          63 G.T. Hawk R-2,4 speed
                          63 Avanti (2) R-1 auto
                          64 Zip Van
                          66 Daytona Sport Sedan(327)V-8 4 speed
                          66 Cruiser V-8 auto

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