i know that the honda guys have had trouble with them, but a while back I decided to email an engine builder about them.
I sent the guys at Endyn an email about the functionality of crank pulleys. My email, and his response are posted below (respectively)
I was reading your article on how to build a naturally aspirated honda
I have heard about people buying aftermarket crank pulleys and having the
crank seals deteriorate at a rapid rate due to a lack of harmonic balancing.
here's my problem: i dont have a honda (2003 Hyundai Elantra)(kidding, this
car isnt so bad), but the engine is incredibly slow revving, and sometimes
it takes a while for the revs to drop. I know that a lighter flywheel would
help a bit, but I dont know if I feel like shelling out $400 and a day for
my incompetent self to install it just yet. a cheaper solution would be an
underdrive crank pulley as well as accessory belts. The car only revs to
6500 rpm and is relatively low powered (120whp). my question is do you
think that the aftermarket crank pulleys destroy seals because they are
inproperly balanced, or because there is no additional balancing effect that
it provides? If you think its because aftermarket pulleys are improperly
balanced, could you prescribe a place to neutral balance an aluminum pulley
for me? (I live in DFW). I really appreciate your help, and look
forward to seeing some more outstanding projects from you in the future.
Balancing has nothing to do with a pulley's inability to dampen crankshaft
harmonics....and lightweight aluminum pulleys don't have the ability to
dampen harmonics either.
Removing mass at the greatest possible distance from the crankshaft
centerline will net the greatest acceleration improvement, so there's
relatively little to gain by lightening something as small as the pulley,
especially compared to what you'd see by removing weight from a
large-diameter piece like the flywheel...
Save your money and do the flywheel...your engine will thank you.
and if you read his board, he says that there is basically no form of racing (save some drag only applications) that use solid mount pulleys (thats what the OBX is). I havent actually taken the time to email a nascar team to ask, but if you're skeptical of endyn, maybe you should take the opportunity to do that.