I got a 1990 Mustang GT crank problem I think

Discussion in 'Fox 5.0 Talk' started by naildriverinnc, Mar 7, 2008.

  1. naildriverinnc New Member

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    I got a shimmy and a shake in the car it's not the harmonic balancer or the flywheel. Does anyone know how the car would act if the crackshaft was bad or could this be the cause of my shimmy and shake:shrug:
  2. LiquidGT New Member

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    Dou you think it could be the driveshaft?
  3. mustangfan1990 New Member

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    I know my crankshaft was bad it caused my harmonic balancer to keep going bad....Dont know if that applies to you I just know that what happened to me
  4. ttop88 New Member

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    Shake all the time? Any noises? Crank is very unlikely. Drive shaft, u-joint or bearing is most likely.
  5. Darkwriter77 Resident Ranting Negative Nancy

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    Is it only while the vehicle is in motion, or while it's sitting still? Does it do it at any speed, or just at a certain speed and higher? Can you see the harmonic balancer wobbling? Is there a clunking/knocking sound coming from the lower end of the motor? :shrug:
  6. mustangfan1990 New Member

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    If it does it no matter what I would say harmonic balancer
  7. naildriverinnc New Member

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    I replaced the harmonic balancer with the original 50oz the rubber seal was pushing out of it. And yes when it's at an idle it's not as bad but when you give it gas it's real bad. It's a 5 speed it shakes in gear and out of gear so I ruled out the drive shaft. It kinda feels like the driveshaft is bent and when your sitting in the seat give it gas feels like it's gonna come through the floor board
  8. naildriverinnc New Member

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    On the pm I got no there is no lose of power at all
  9. Darkwriter77 Resident Ranting Negative Nancy

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    So, you're saying it vibrates in or out of gear, either while moving or while at a standstill, and the vibration coincides with RPM's, correct? That pretty much rules out anything from the tranny on back, then, so at least you've narrowed it down to something with the motor. I still doubt that it's the crank, itself, though.

    Even though you replaced the balancer before, have you looked at it to see if it's still wobbling? It's possible that you got a defective one, or that it may have been installed incorrectly/damaged during install (it happens).

    Only other thing I can think of is, being that it's a 5-speed, is that your flywheel may be out of balance somehow. Either one of the tack-welded weights might've come off somehow, or it may not have been properly torqued down if/when it was last serviced, and so it's wobbling like mad. Do you have any vibration in the clutch pedal?
  10. BLOWN 5.0 FOX Member

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    hows your motor mounts??
  11. naildriverinnc New Member

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    Motor mounts are good
  12. naildriverinnc New Member

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    I'll check to see if I the balancer is wobbling and the clutch pedal for a vibration tomorrow. I had the flywheel off to check it and it looked good.
  13. 5.0Droptop Neutered Member

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    Has this engine been rebuilt? If so was it a 28 oz balance or 50 oz balance? If its a 28 oz balance and you put a 50 oz balancer on. It will shake.
  14. naildriverinnc New Member

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    No you can't feel it in the clutch and the harmonic balancer ain't wobbling. It's got a new 50oz balancer on it i installed a new one and the flywheel is also a 50 oz.This is all the guy I bought it from had done to it NEW 5.0L CRATE ENGINE W/ GT40 HEADS AND VALVE TRAIN
    - NEW NEW WORLD T-5 TRANS AND SHORT THROW SHIFTER
    - NEW 3.73 GEARS
    - NEW HIGH PERFORMANCE FORD
    MOTORSPORT CLUTCH
    - COBRA INTAKE AND 70MM THROTTLE BODY
    - COLD AIR INTAKE & UNDERDRIVE PULLEY'S

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