When I rebuilt my old SAAB V4 I had it balanced.  If done right, it's
expensive and does wonders for the motor.  I seriously doubt that the
factory goes thru the effort that a true balance process requires.

You literally have to grind away metal with a dremel until all moving parts
weigh exactly the same.  The process takes into account the weight of
the bearing and rings as well.  A jig is used so these weights are dynamic
not just static.

My V4 cost $250 about 7 years ago.  I imagine a 6 would run upwards
of $500 these days.

The result was an engine that ran smoooooth, put out more power with
less gas.  I was able to take several pounds OFF the flywheel with no
sacrifice to smoothness, making the engine rev faster as well.

The flywheel was balanced and marked to the crank for correct orientation.

Seems odd that the flywheel would be unbalanced on purpose.  You would
want that to occur on the crankshaft counterweights, else the loads
on the end of the crank end near the flywheel would be extreme.

- Frank (a firm believer in balanced engines)

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Frank Terhaar-Yonkers,  Manager
High Performance Computing and Communications Research
MCNC
PO Box 12889	3021 Cornwallis Road
Research Triangle Park,  North Carolina  27709-2889
fty@mcnc.org   voice (919)248-1417   FAX (919)248-1455

http://www.mcnc.org/hpcc.html