Editing Straight-six engine (section)

=== Engine balance and vibration ===
[[File:Inline 6 Cylinder with firing order 1-5-3-6-2-4.gif|thumb|Typical firing order of 1-5-3-6-2-4]]
[[File:marinestraight6.jpg|thumb|upright|right|3890-litre ''MAN B&W 6S60MC'' marine diesel engine]]

If an appropriate [[firing order]] is used, a straight-six engine has perfect primary and secondary [[engine balance]]. The primary balance is due to the front and rear trio of cylinders moving in pairs (albeit 360° out of phase), thus canceling out the rocking motion present in a [[straight-three engine]]. The secondary balance is due to the [[crank throw]]s being arranged in three planes offset at 120°, resulting in the non-sinusoidal forces summing to zero for all free forces until the sixth order.

The engine balance characteristics of a straight-six engine compare favorably with the more common [[straight-four engine]]s, [[V6 engine]]s, and [[V8 engine]]s which experience significant secondary dynamic imbalance, resulting in engine vibration.<ref name="Nunney">{{cite book|last=Nunney|first=M J|title=Light and Heavy Vehicle Technology |edition=Fourth |publisher=Butterworth-Heinemann |year=2006 |isbn=0-7506-8037-7}}</ref>{{refpage|pp12-13}} As engine reciprocating forces increase with the cube of piston bore, the straight-six is a preferred configuration for large truck and industrial engines.<ref name="Nunney"/>{{refpage|pp40-47}}