It sounds like something let go in the clutch. Pressure plates in DS & DST
type clutches (B&B, QH) move off-centre and cause unpleasant vibrations,
sometimes sufficient to break the crank.BTW the ubiquitous Haynes manual
gives the wrong torque for 6-cyl flywheel bolts- 46ft/lb (correct for
TR2-4A). 90 ft/lb is the correct figure, or if you use the good ARP bolts,
up to 115 ft/lb can be used. Sometimes the starter ring gear moves backward
on the flywheel unevenly- another possible cause. I think the damper is
unlikely to be involved. Certainly flywheel related bad vibes do manifest
themselves exactly in this rev. range.
Jon C.R.
----- Original Message -----
From: "kas kastner" <kaskas@cox.net>
To: <Jasonsmf@cs.com>; <FOT@autox.team.net>
Sent: Thursday, August 21, 2003 7:02 PM
Subject: Re: TR6 engine vibration..
> I suggest pulling off the starter motor and seeing if the flywheel is
loose.
> ----- Original Message -----
> From: <Jasonsmf@cs.com>
> To: <FOT@autox.team.net>
> Sent: Thursday, August 21, 2003 9:56 AM
> Subject: TR6 engine vibration..
>
>
> > Amici.. Our TR6 has developed a pretty nasty vibration in the
> engine that starts right around 2900 RPM (or so the 31 year old tach
> reads)and continues up to around 3200 RPM. This vibration seemed to
appear
> on it's own, without any changes being made on the car. The engine has
been
> internally balanced (a couple years prior to this problem). I'm pretty
sure
> the vibration is from the engine, it will vibrate weather the car is
moving
> or stopped, neutral or in gear, clutch engaged or dissengaged, none of
these
> make any difference. The engine has been tore down to the bare block
since
> then, everthing seemed to be OK inside (bearings good, all rotating parts
> visually good...). I'm not sure what is going on. Could the crank damper
> have gone bad and no longer damp a harmonic at this RPM?? This car still
> sees some street duty and this vibration is right smack dab in the meat of
> crusing RPM. This vibration can really be felt strong if I hold my hand
on
> the intake manifol!
> > d as I free rev the engine as the rev's fall off through this 2900-3200
> rpm range. Any ideas??Thanks in advance.Jason Sukey
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