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Hot Rods Driveline Vibration

Discussion in 'The Hokey Ass Message Board' started by Bonehead II, Jun 2, 2019.

  1. gimpyshotrods
    Joined: May 20, 2009
    Posts: 18,384

    gimpyshotrods
    ALLIANCE MEMBER

    In all 2-joint applications, the imaginary line, viewed from the side of the vehicle, that passes through the crankshaft and transmission, and the imaginary line that passes through the pinion should be exactly parallel (you pedants who will bring up bushing compression, chassis flex, and spring deflection, can shut it).

    Let's get this guy fixed up!
     
  2. gimpyshotrods
    Joined: May 20, 2009
    Posts: 18,384

    gimpyshotrods
    ALLIANCE MEMBER

    It is the equal-but-opposite operating angles that cancel vibration. You don't have this.

    -5º/+5º would be equal. You have -5º/+8º.

    -5º/+5º might still be too far to fully alleviate this issue, but it will help.

    Remember, you need to measure these angles with the vehicle on level ground (or equivalent), with ALL vehicle weight on the suspension.

    If it does not go away, do whatever you can to reduce the slope of the engine/trans/overdrive combo. Even if that is just a single degree. Correct the pinion angle to match that new angle. Every little will help. Even just a 1/4" shim under the transmission mount will help.
     
    BJR likes this.
  3. You have a few issues there
     
    gimpyshotrods likes this.
  4. moparjimd60
    Joined: Jan 22, 2018
    Posts: 71

    moparjimd60

    I was afraid you were going to say that, it is a blown hemi in a 32 frame and the bottom pulley is as low as it can go or hit the crossmember any other ideas?


    Sent from my iPad using H.A.M.B.
     
  5. Bonehead II
    Joined: Apr 18, 2005
    Posts: 428

    Bonehead II
    Member

    I will lower the pinion and put a shim under the trans. and see what happens.
    Thanks to everyone who helped....Mike.
     
  6. gimpyshotrods
    Joined: May 20, 2009
    Posts: 18,384

    gimpyshotrods
    ALLIANCE MEMBER

    Correct the pinion angle to what I indicated. See if that is enough.

    If not, cut the crossmember.

    If you won't do that, you will need a double-cardan driveshaft. That has three joints, two of which are in close proximity, linked to each other, and articulated, at the front end of the shaft. These are most commonly used in the off-road world, when you have excess deviation in height between the transfer case, and the pinion, with too short a drive shaft.

    You actually have exactly that, just upside-down. The drivetrain does not know what is up, or down. It's just metal.
     
    moparjimd60 likes this.
  7. Cut the floor out and raise the transmission where it’s supposed to be.

    If it’s got a rubber rake and a engine at 5* it’s needs done

    Study ago’s @ago 32
    He’s got it all stuffed in there
     
  8. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,912

    dirty old man
    ALLIANCE MEMBER

    Seems to me that something's off base here in this thread about pinion centerline and transmission centerline related to each other. Whether the pinion shaft is higher or lower than the transmission shaft is immaterial.
    What matters is that the centerlines. of transmission and pinion be parallel so that the angles are opposing each other, which cancels out the variation in the rotation at the pinion shaft. IOW, if the rear of the trans centerline is angled down, then the pinion shaft centerline should be angled up at an equal but opposing angle. these equal but opposing angles will cancel out pulsations at the pinion.
    Working angle enters into this simply as to the angle limits of the U joint used, and of course wear generated by excessive working angle. Some angle is needed in order to move the needle bearings around in their respective bearing cups.
    Working angle is established by the length of the driveshaft and the distance apart of the 2 centerlines which must be parallel to each other. If working angle is too much then you have to juggle things around, and possibly add a third U joint, preferably a constant velocity joint.
     
    X-cpe and BJR like this.
  9. Ziggster
    Joined: Aug 27, 2018
    Posts: 914

    Ziggster
    Member

    I stand corrected. Spicer mentions a max operating angle of 3*, but 1* is ideal. Also depends on speed of driveshaft. The attached pic might help. If correct, your first operating angle is 10* and your second is 13* which are both way over the maximum recommended. However, if I enter the data into the Spicer Calculator (5* down for trans; 5* up for driveshaft; 8* up for pinion) it gives operating angle of 10* at trans and 3* at pinion which is counter to pic below for the pinion angle. Everything I can find on the net is not clear on when you add and subtract the angles.
    image.jpeg
    Link to Spicer calculator:

    https://spicerparts.com/calculators/driveline-operating-angle-calculator
     

    Attached Files:

  10. The Mullet
    Joined: May 19, 2018
    Posts: 43

    The Mullet

    You could try a CV drive shaft but will need to change your pinion angle so it points directly at the rear of the OD

    Sent from my XT1650 using The H.A.M.B. mobile app
     
  11. The Mullet
    Joined: May 19, 2018
    Posts: 43

    The Mullet

  12. Someone set this up wrong.
    .., they stuck the drivetrain in the car and “made it fit”
    They missed the mark on “ make it work”
    C9E17D1B-1045-4B82-8986-AA91C56CA5D3.jpeg

    I’d like to see pics of the whole car.
    Profile, rake, firewall, interior trans tunnel.

    Draw a 32 ford around that drivetrain and it’s got to be odd looking
     
    gimpyshotrods and 57 Fargo like this.
  13. 48stude
    Joined: Jul 31, 2004
    Posts: 1,192

    48stude
    Member

  14. Bonehead II
    Joined: Apr 18, 2005
    Posts: 428

    Bonehead II
    Member

    Hey Guys, just to let you know I lowered the pinion 4* and it seems that all is well.
    Thank You all for your help.....Mike
     
    Terrible80 likes this.
  15. Bonehead II
    Joined: Apr 18, 2005
    Posts: 428

    Bonehead II
    Member

    Here is couple of shots , more to follow.
     

    Attached Files:

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