RE: 75 Driveshaft balancing

["John Fielding" <johnf@domain.elided>]

Hi All,

A very knowledgable friend who runs a balancing shop here advised about me
the Alfa transaxle clutch assembly.  In his long experience ALL of the ones
he has had through his shop have been severely out of balance.  The folks
who lighten theirs are looked upon with dismay by this person.  He strongly
advised me against doing this to our Alfetta race car.  The clutch flywheel
is pretty skinny as standard and it is common for these to literally explode
if lightened to any degree.  I saw a transaxle case a few weeks back where
the owner had made a rush job of replacing the clutch friction disk without
having it rebalanced.  It had more than half of the casing missing where the
clutch flywheel had let go!

A second fact that I learnt the hard way was when replacing the donuts.  I
have recounted this tale before but it bears repeating.  I changed the
broken front donut and after what can only be described as a real PITA
weekend on my back I was sorely disappointed to find the driveshaft vibrated
like a real b**tard!  Thinking I had missed some vital step I went crying to
my friendly Alfa guru on Monday.  He smiled and told me they usually do that
when a new donut is installed.  Apparently the rubber is very stiff when new
and needs softening before the vibration goes away.  The cure is simple.
Find the revs which cause the worst vibration and set the idle to there.
Run the motor for one hour and switch off and let it rest for a couple of
hours.  BTW Whilst doing this turn up the TV or radio to drown out the
noise!

Repeat this for an hour at a time until the vibration dies down.  In my case
I ran the motor every evening when I got home from work and it took 4
evenings before the problem went away.  After this the driveline was silky
smooth!  Thought you all would like to know.

John Fielding
Durban
South Africa

Alfetta 1.8L turbo & GT40 on the way!

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