Posted by Oscar
on 11/7/2009, 8:17 am, in reply to "Re: Vibration"
76.111.144.201
For years, my GT6 had a real bad vibration problem. I also checked everything connected to the drivetrain. Then, someone at this site (I think it was Glen) suggested I recheck my driveshaft. I found that the rear u joint of my driveshaft was slightly loose. I replaced it and I can now go 70 MPH without fear that one of my wheels might come off.
--Previous Message--
: I would get the shaft balanced before
: going any further; at this point it is
: an unknown quantity. It may be fine
: but, but you WILL be very upset if you
: chase your tail around only to find out
: that the shaft IS the problem after all
: .
: Also realize that a lot of shops will
: just check the runout & calculate
: the amount of weight needed, and/or
: spin it at low speed. These shafts are
: long (and, depending on the shaft you
: have, several are large diameter), and
: they don't take much imbalance to get
: them jumping around. Eventually the
: tailshaft housing will crack, then the
: real bad stuff happens...
: The "whine" may or may not be
: related, but if you have followed all
: the recommendations so far, I think you
: would have discovered something by now.
: Hang in there, you'll get it...
: Glen
:
:
: --Previous Message--
: The drive shaft is refurbished but not
: rebalanced. Ouch-I had a sneaky
: feeling I should have rebalanced the
: shaft. What else could it be in the
: rear end? I do hear a bit of a whine
: when I accelerate at highway speed but
: assummed that was the engine.
:
: --Previous Message--
: Well that's actually good, it rules out
: everything from the gearbox output
: forward, but, conversely, everything
: aft is suspect...
: Which type slider is on your
: driveshaft?
: Is the replacement shaft
: new/used/rebuilt/balanced?
: Please excuse my paranoia about the
: driveshaft but I have many
: horror-stories about imbalanced
: Spit/GT-6 driveshafts...
: Glen
:
: --Previous Message--
:
: At speed on the highway, vibration is
: there but feel it more on acceleration.
: At 75+ vibration is constant and
: doesn't diminish until I coast to below
: 60- even with the engine idling.
: --Previous Message--
:
: Hmmm... how 'bout when you're running
: along in top gear, steady throttle,
: during the vibration period, or is it
: only under acceleration?
: If it is there at steady speed, does it
: go away immediately if you just pop it
: into neutral and let the engine come
: down to idle, while the car is still in
: this speed range?
: Glen
:
: --Previous Message--
: Test results from the commute this
: morning. Vibration worst in 3rd and
: 4th gear at 3-4,000 rpms when
: accelerating. Not really evident in
: 1rst and 2nd at the same rpms. It
: doesn't stop until I hit 50 mph or so
: if I push the clutch in and coast when
: the vibration starts. Seems like a
: feedback vibration so I am wondering if
: something is loose in the rear end (the
: front end is tight).
:
: --Previous Message--
: OK... is there any vibration when it is
: in neutral ie no-load, hot or cold?
: Glen
:
: --Previous Message--
: Compression was checked when we ported
: out the engine- is fine. Another
: possible clue, vibration is worse
: before the engine is warmed up.
:
: --Previous Message--
: It might be good to do a compression
: test
: if you have not done it yet.
:
: --Previous Message--
: If it pulls cleanly & makes good
: power, it's likely OK. If you were
: losing a cylinder it would make a
: vibration... but you would feel the
: loss of power.
: Glen
:
:
: --Previous Message--
:
: I don't think any questions are stupid
: when it comes to triumphs.
: (particularly-why did they design it
: that way?) Question for you- how can I
: tell if it is a missfire? The engine
: has plenty of power. It does idle a
: tad rough- RPMs move up and down a bit.
: --Previous Message--
: OK a stupid (maybe not) question...
: could
: this possibly be an engine misfire
: induced vibration that you feel?
: Glen
:
:
: --Previous Message--
: Some success, the steering rack was bad
: and has been replaced, the rest of the
: front end is tight and checked out
: fine. The "hopping" is gone.
: Vibration on the highway is down
: substanially and the car tracks well
: now. However, there still is some
: vibration, particularly when
: accelerating, that I can feel
: "through the seat" and the
: gas pedal- not so much through the
: steering wheel. The drive shaft has
: been replaced already. Anyone have any
: other thoughts? It would be nice to
: get the car vibration free.
:
: --Previous Message--
: Have you tried swapping the wheels
: front
: to rear/rear to front, see if it
: changes?
: Also is there ANY change in the engine
: "smoothness" in that RPM
: range with no load ie neutral?
: If the gear lever is not shaking, and
: there is no seat-of-the-pants vibe or
: "drone" from the rear of the
: cockpit, the driveline is likely OK.
: If there is wear in ball joints, t/r
: ends, trunnions, rack mountings, etc,
: it doesn't take too much imbalance to
: get a vibration going, ultimately
: resulting in the steering wheel
: shimmy...
: Glen
:
: --Previous Message--
: Hi Glen- It's a vibration I can feel
: through the wheel and the accelerator
: pedal. The gear shift lever is fairly
: stable. It is worse when accelerating
: at the wrong RPMs as mentioned.
:
: --Previous Message--
: Couple questions,do you get the...
: Gear lever "buzz"?
: Steering wheel shake?
: Scuttle (dash & cowl) shake?
: Also always consider the opposite
: diagonal corner when trying to isolate
: suspension issues...
:
: --Previous Message--
: Thanks to all who commented previously.
: I replaced the drive shaft in my gt6.
: Tires are balanced, new shocks,
: trunnions greased, new bearings.
: Vibration is better but still exists in
: 3rd and 4th gear at 2800 to 3300 RPMs.
: Seems to eminate from the right front
: and is worse when accelerating. May be
: connected but have an issue of the
: front end "hopping" on hard
: right turns at slow speeds when
: accelerating.
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