My 360 build.

Wyrmrider said

OK
my 2 cents on the balance
you balance 100% of the rotating weight- you are not changing that
you only factor in 50% (or so) of the reciprocating weight
which is the rod small end, piston, pin, rings
not an exact science
so what? 50% of the difference in piston weight?
so you end up overballanced a little figure out how much
what impact does an overballance that size make
who overballances Dilibertly and why?
in which plane would any overballance shake be felt- H or V
would motor mounts hide?

Click to expand...

FWIW...... 50% of the piston weight change is doubled because there are 2 piston/rod assemblies represented by each bobweight. So, if you're thinking of it in that fashion, then think of 100% of the piston weight change going into the bobweight.

The over- or under-balance creates a rocking motion in the engine at the same rate as the RPM's. Imagine passing an imaginary axle through the #3 main bearing, and the engine rocking back and forth on that... .front is going up while rear is going down and vice versa, back and forth once per crank rotation. The trannie and its mounts tends to limit this rocking motion, but then those forces all go into the front and rear of the bearings, crank, block etc.

The balancing of the piston/rod assemblies minimizes a different imbalance around the main axis of the crank.