Shawn,
Did you have the drive shaft balanced at a drive shaft specialist?
They have a machine that balances it at high speeds. Sounds like this may
be it.
Mike MacLean
60 Sprite
shk wrote:
> I posted a couple of months ago about vibration I had in my '63 Sprite.
> It has a 948 with a ribcase. The vibration is strongest around 3K
> RPM. Several people suggested I replace my U-joints which I did
> but unfortunately it didn't help. I've had an opportunity to
> road test the car some since then and I have discovered some things
> of note. You can really feel the vibration through the shift lever.
> Most curious though is if you "bump" the clutch slightly so that the
> disc slips a little you can make the vibration go away. If you keep
> doing this you can cause the vibration to fade in and out. As if some
> harmonic vibration is passing in and out of phase. The RPM range which
> leads to the vibration is very localized, about 400 RPM. I am not
> certain about 1st or 2nd, but the vibration is there in both 3rd and
> 4th gear. I am thinking this may be caused by the pilot bearing or
> maybe bearings on the transmission input shaft. Or maybe even a bent
> shaft. I suppose another possibility would be the clutch. Anybody
> tackled a similar problem, or have any suggestions?
>
> Shawn
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