Engine Vibration (Main)

Vibration accelerates wear, breaks parts and robs power.  There are three types of engine vibration that professional engine builders concentrate on minimizing.  Each has its own method to control it.  They are:


Unbalanced vibration

Unbalanced vibration is what comes to mind first.  It is a weight imbalance vibration that occurs once per revolution.  Like the consistent thumping you feel when you lose a wheel weight.  In regards to an engine, even measure and distribution of the rotating assembly weight prevents this.  A balancing service refers to precision matching the pistons, connecting rods and crankshaft counterweights to minimize unbalanced vibration.



Axial vibration

Axial vibration is forward and backward movement of the crankshaft.  The main bearing support plate and thrust bearings are in place to avoid this movement.



Torsional vibration

Torsional vibration is the end-to-end twisting and rebounding of the crankshaft caused by combustion.  The harmonic balancer (damper) controls the twist to achieve durability and efficiency. Not all are constructed or function the same. 

Important note.  A balancing service does not remedy torsional vibration.  A harmonic balancer only effects unbalanced engine vibration if it contains a counterweight.  This is referred to as an external balanced engine.  Today the Ford Power Stroke and Chevy Duramax fall into this category.  Classic external balanced engines include the Ford Windsor and 454-502ci Chevy Big Blocks.

Fluidampr specializes in torsional vibration.  Parent company, Vibratech TVD is a solutions provider to global powertrain OEMs.  Including several prestigious automotive and marine brands.  With over 70 years of experience, the company currently designs and develops the widest range of torsional viscous dampers in the industry.  Powertrain torsional vibration control applications include crankshafts, camshafts, drivelines and electric drives.

Engine vibration.  Torsional vibration measurement.Laser sensor for measuring crankshaft twist.

Engine Vibration By Any Other Name

Three unique movements of engine vibration.  Three completely different ways to control each.  It is important to know the differences to understand what parts and services are best for your engine build.

You may hear all three grouped into the general term, engine harmonics.  The Noise, Vibration Harshness (NVH) automotive engineering field also focuses on these vibrations and how it impacts consumer quality.  Terminology nuances can lead to confusion.  You can rest easy knowing that managing these three engine vibrations here is a fundamental step to achieving a high quality, long lasting build no matter what it’s called.