In a message dated 96-06-22 23:42:27 EDT, jscohen@m2.sprynet.com (James
Cohen) writes:

<< 
 I haven't heard that before.  If that is the case, why is the red line on
 the wasserboxer tach all the way up to 6000rpm?  (or thereabouts, I just
 know that it goes well beyond 4000).
 
 I did know that the red line on the ac is 4400 rpm, however.
  >>
The Engine control computer is set to cut out the fuel at about 5400 rpm.
 The engine will withstand higher speeds for short durations , but why push
it.  The big problem is the boxer motion coupled with a non counter wieghted
crank,(counter wieghts and balancing are different issues).  When reeved too
high, the crank does bend and twist a bit.  This flexing is especially hard
on the center bearing.  As this bearing is a split bearing, the forces are
directed to the case which then gets distorted.  American cars,( and Audis)
use a harmonic balancer on the pulley end of the crank to reduce some of the
crank twisting.  These engines need this due to the longer crankshafts and
higher loads placed on the crank.