How to Redesign a Crankshaft for Dual Connecting Rods?

[ydeardorff]

I am redesigning a crankshaft to support two connecting rods per journal from it's stock one per journal.
I will be machining a new crankshaft out of 4340 billet. This design will reduce the counterweights to 9mm in thickness.
This engine is a 9k redline design so I need to get this right.

Can anyone point me in the right direction? I need to map out the current 6 cylinder crankshaft. But a direction on the counterweight design formulas , and design process would be of great help.
Yaughn

 

[autodoctor911]

what kind of straight six are you trying to make into a v12?

If your counterweight s will be 9mm narrower, and you will be putting two rods and pistons on each trow instead of one, the counterweights must be made heavier somehow. Heavy metal may be needed, or adding counterweights where there were none before.