One way to balance an Alfa Drive shaft...

[Scott Goodwin <scotti@xxxxxxxxx>]

I was able to successfully balance the drive shaft of my GTV/6 without too much difficulty.  Here's what I found:

1)  Most drive-line specialty machine shops don't know what to do with a 2-piece drive shaft.  Further, they throw
up their hands when they see the tripod yokes at each end of the drive shaft(s).  It won't fit in their balancing
machines.

2)  Take the two sections apart, make marks on the respective halves so that you can put it back exactly the way
it was (although I would argue that if you have two, perfectly balanced halves, it doesn't matter how the two
pieces go back together).

3)  Call around your area and find a shop that does engine balancing.  Any shop that can balance an engine can
balance each half of the drive shaft.

4)  The only snag the technician will run into is that the ends of one of the shafts (I forget which half) are
different diameters.  When in the balancer, the shaft will be supported on either end by a "V" block.  As such,
the half with the different ends won't be perfectly horizontal in the balancer.  We had to make a crude bushing to
make the ends the same diameter.

5)  On the shaft that has the removable tripod (with splines), be sure to leave that piece ON while you are
balancing it.  The position of the tripod piece IS critical to the balance of just this half of the drive shaft
assembly.  The tripod piece is a rather crude casting and is visibly heavier on some lobes than others.

6)  Balancing is accomplished by welding small pieces of metal to the shaft itself (as indicated by the computer
on the balancer, or an analog meter on the old-style balancers).

7)  Once you have two perfectly balanced halves, the ONLY other variables that could impact the balance of your
entire drive shaft assembly are A) the drive doughnuts (which you have NO control over), and B) the nuts, bolts
and washers used to bolt the pieces together.

8)  If you really want to be anal retentive, put all the nut/bolt/washer assemblies together and weigh them
individually on a scale.  Use a grinder to remove metal from the heaviest 2 of the 3 assemblies (i.e.. match the
weight of the lightest set).

I did all this stuff (OK I didn't balance the bolts...), and even having lost the position of the two shafts with
respect to each other, my drive line is smooth as a baby's butt at all RPM's.

Good luck and happy (smooth) motoring.

Scott Goodwin
Austin, Texas
82 GTV/6 Balocco 3.0
scotti@domain.elided