Flywheel imbalance

[Jerry Clayton]

Callies 302 Ford stroker
Holes drilled and reamed for 1 inch pieces of Mallory heavy metal to internal balance

[xb-60]

Thanks Jerry. That does seem more sophisticated than an external balance, but no doubt horses-for-courses.
Would a corrective imbalance flywheel and front balancer tend to induce some flex into the crank, as the masses are applied some distance from the imbalance they are trying to correct?
Cheers,
Glen

[xb-60]

I was doing a bit of trolling around, and saw reference to an SFI balancer for an internally balanced engine - why do you need one for an internally balanced engine?
"Pioneer part number 872034 ... for... Ford SB 302-351W with 6.37" Dia Internally Balanced"

I'm some way off talking to an engine builder, so I'm 'chewing-the-fat' a little here...

Cheers,
Glen

[blykins]

You need a harmonic balancer to take out the harmonics of a rotating assembly...which even internally balanced assemblies have harmonics.

The SFI rating just shows that it's been approved by SFI guidelines, which is a standard for most racing sanctions.

[xb-60]

Understood....so if an engine is internally balanced or not, it still needs a harmonic balancer. The harmonic balancer for an internally (zero) balanced engine would obviously (yes?) be different to that of say a 28oz/in engine?
Cheers,
Glen