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408W Rotating Assy Balance

  • Thread starter Thread starter js66coupe
  • Start date Start date Jan 9, 2011
J

js66coupe

Member
May 10, 2009
49
0
7
Florida
Jan 9, 2011
#1
  • Jan 9, 2011
  • #1
It's my understanding that the 351W uses an external balance weight to balance the rotating assy. I am seriously considering having the rotating assy. internally balanced so I don't have to run external balance weights. Has anyone here done this? TIA
 

rbohm

Founding Member
Apr 12, 2002
6,698
550
204
tucson,az
Jan 9, 2011
#2
  • Jan 9, 2011
  • #2
yes it has been done, and there are even flywheels and balancers that you can buy that are for zero balanced engines.
 
J

j69302

Active Member
Jan 31, 2006
325
1
29
Jan 9, 2011
#3
  • Jan 9, 2011
  • #3
is there a benefit to having a internal balance assembly vs external?
 

rbohm

Founding Member
Apr 12, 2002
6,698
550
204
tucson,az
Jan 10, 2011
#4
  • Jan 10, 2011
  • #4
j69302 said:
is there a benefit to having a internal balance assembly vs external?
Click to expand...

not really. the weight of the rotating assembly comes out the same either way, though some will say that an internal balanced engine will run slightly smoother, but the reality is that unless you are going racing at the highest level, an external balanced engine is going to feel and work just like an internally balanced engine, and both will last as long as the other will.
 

BuckeyeDemon

Member
Apr 13, 2010
130
9
19
Cincinnati, OH
Jan 10, 2011
#5
  • Jan 10, 2011
  • #5
if you're planning on getting a new damper, flywheel and forged crank then go internal. if you have a cast crank then don't even consider it.
 
M

mycoses

New Member
Jul 29, 2010
18
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Jan 11, 2011
#6
  • Jan 11, 2011
  • #6
Internal balance allows you to replace the flywheel and balancer(neutral balance) anytime without the need to rebalance the engine. Also precludes the need to deliver the flywheel and balancer to the engine builder when the engine is being assembled.
 
6

65coupe408w

Member
Mar 26, 2010
192
0
16
Jan 11, 2011
#7
  • Jan 11, 2011
  • #7
my 408w is zero balance. I have no regrets about having this done. I feel the motor revs up extremley quickly which is likely helped by the lack of a counter weight on the flywheel.
 

Wicked65

Member
Aug 10, 2003
490
3
19
NORCAL
Jan 11, 2011
#8
  • Jan 11, 2011
  • #8
Id go with what 65 Coupe said. If you really want to see a difference, do a zero balence. But really, id take a look at what your going to be doing with the motor to see if that extra money is even worth it. later model 351's are all 28oz already. and honestly, mine revs pretty damn quick.
 

blown65

Founding Member
Jul 7, 1999
1,938
4
39
Queen Creek Arizona
Jan 11, 2011
#9
  • Jan 11, 2011
  • #9
rbohm said:
not really. the weight of the rotating assembly comes out the same either way, though some will say that an internal balanced engine will run slightly smoother, but the reality is that unless you are going racing at the highest level, an external balanced engine is going to feel and work just like an internally balanced engine, and both will last as long as the other will.
Click to expand...


Going to pretty much agree with this. No reason to internally balance a street motor IMO. Turning some high revs then ya, definitely go internal.

Internal balancing can get pretty spendy if your crank is needing heavy metal.
 
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