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Technical FE guys- crank pulley question

Discussion in 'The Hokey Ass Message Board' started by Ryans65, Oct 30, 2025 at 5:50 PM.

  1. Ryans65
    Joined: Apr 12, 2018
    Posts: 150

    Ryans65
    Member
    from Yulee FL

    On my 63 country squire there is a very rhythmic vibration from about 1000 rpm's through 1500 or so then it comes back in the 2000 rpm range but smoothes out after that as I'd expect from some sort or lower end imbalance. This is a stock 352 with stock cruise o matic. I've ruled out ignition and compression/ valve train issues as I've had both valve covers off recently and did a compression/ leak down test. It idles very smooth too with no noticeable "chuffing" from the single exhaust. Im sort of moving in the direction of the crank pulley but I don't think I'm dealing with a spun balancer but maybe just worn out rubber? The only visual indication I see of this is a piece of rubber sort of sticking out where it's vulcanized to the pulley. This is my first FE so I'm still learning but certainly not my first old car. Just wanting to see how much that pulley has to do with engine balance/ harmonics. Doesn't seem to be much meat on it.
     
    chryslerfan55 likes this.
  2. Ryans65
    Joined: Apr 12, 2018
    Posts: 150

    Ryans65
    Member
    from Yulee FL

    Not sure if anyone can tell but there's a small flap towards the bottom sticking out. I'm****uming it's also 62 years old. haha IMG_1204.png
     

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  3. Oneball
    Joined: Jul 30, 2023
    Posts: 1,603

    Oneball
    Member

    I’ve got a 1962 and the rubber doesn’t bulge like that could just be a difference in the way they’ve been made IMG_6513.jpeg IMG_6581.jpeg
     
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  4. jimmy six
    Joined: Mar 21, 2006
    Posts: 16,972

    jimmy six
    ALLIANCE MEMBER

    Send it to the Damper doctor in central California for rebuild and balance…There’s also the Damper Dude in the same general area….
     
    alanp561 and Oneball like this.
  5. tb33anda3rd
    Joined: Oct 8, 2010
    Posts: 17,573

    tb33anda3rd
    Member

    take all the belts off and run it, see if the vibration is still there.
     
    loudbang, 3blapcam and alanp561 like this.
  6. 64gal
    Joined: Jan 18, 2007
    Posts: 148

    64gal
    Member

    I doubt its the dampner, they are "0" balance.More likely sacked out engine mounts,or something fouling against frame.
     
    alanp561 and Crazy Steve like this.
  7. Ryans65
    Joined: Apr 12, 2018
    Posts: 150

    Ryans65
    Member
    from Yulee FL

    Interesting, I'll get a closer look at mine tomorrow.
     
  8. Ryans65
    Joined: Apr 12, 2018
    Posts: 150

    Ryans65
    Member
    from Yulee FL

    I think I'll do this tomorrow, good suggestion.
     
  9. Ryans65
    Joined: Apr 12, 2018
    Posts: 150

    Ryans65
    Member
    from Yulee FL

    I meant to put my jack under it this evening while running to lift the engine up slightly and see it made any change, the mounts look good but then again they could be some chinese replacements. Not sure on when they were done but they don't look like a burned marshmallow like most old mounts.
     
  10. alanp561
    Joined: Oct 1, 2017
    Posts: 5,507

    alanp561
    ALLIANCE MEMBER

  11. Ryans65
    Joined: Apr 12, 2018
    Posts: 150

    Ryans65
    Member
    from Yulee FL

    On these cruise o/ 352 combos was there a pilot bushing for the torque converter in the crank or was the end of the crank machined to receive the protrusion on the torque converter? The manual doesn't explicitly say there is a machined dowel for automatics, it covers manual trans obviously but didn't see anything with regards to automatics.
     
  12. No bushing. The convertor indexes directly into the crank. And I've seen much rattier dampers than yours run with no issues. As long as it spins true it should be OK.
     
  13. Ryans65
    Joined: Apr 12, 2018
    Posts: 150

    Ryans65
    Member
    from Yulee FL

    Ok thank you I can rule that out then!
     
  14. corncobcoupe
    Joined: May 26, 2001
    Posts: 8,693

    corncobcoupe
    SUPER MODERATOR
    Staff Member

  15. FrozenMerc
    Joined: Sep 4, 2009
    Posts: 3,395

    FrozenMerc
    Member

    Does the vibration happen in gear, when driving, or just sitting in neutral and bringing the revs up?

    When you say rhythmic, I interpret that to indicate something is hitting a natural frequency resonance and generating a low frequency, high amplitude vibration. That would most likely come from a drive shaft or a tire imbalance, hence my first question. In other words, can you give us some more details to help narrow down the source of the vibration?
     

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