Taking It For A Spin: Why Are Some Crankshafts Externally Balanced?
If you’ve ever driven with a missing wheel weight, you’ve experienced how just a little bit of imbalance can cause a whole lot of vibration. It’s not hard to imagine, then, how a properly balanced crankshaft can result in a smoother running engine, less bearing wear, and reduced parts breakage.
Although all stock engines leave the factory with an assembly-line-quality balance, the balance of the rotating assembly can often be improved. In balancing the rotating assembly, the weight of the crankshaft counterweights offsets the rotating and reciprocating forces of the piston/rod assemblies. But why are some engines internally balanced, while others are externally balanced? We’ll get to that, but first, let’s look at how an engine is balanced.
