Editing Flat-six engine (section)

== Engine balance ==
{{see|Flat engine}}
A [[boxer engine|boxer-style]] flat-six engine is able to have perfect [[primary balance|primary]] and [[secondary balance]]. As in other six-cylinder engines, the overlapping of the power strokes of the different cylinders (with a firing interval of 120 degrees in a four-stroke engine) reduces the pulsating of the power delivery relative to that of similar engines with fewer cylinders. 

In a [[boxer engine|boxer]] configuration, a flat-six engine does not have a [[Couple (mechanics)|rocking couple]]. The symmetry of the arrangement, in which one bank of three cylinders is mirrored by the other bank, means that there is no net force from any given mirrored cylinder pair along the axis of movement of the pistons. So not only is there no net primary or secondary reciprocating effect, there is no net turning force - moment - that would try to rotate the engine back and forth about its engine mountings. (The moment is not quite zero in practice because each cylinder pair is offset slightly from the other, or else they would clash at the crankshaft.) In this regard, the six cylinder boxer engine is the same as a flat-four boxer engine, which also does not experience any rocking couple.<ref>{{cite web |title=The Physics of: Engine Cylinder-Bank Angles |url=https://www.caranddriver.com/features/a15126436/the-physics-of-engine-cylinder-bank-angles-feature/ |website=www.caranddriver.com |access-date=9 September 2019}}</ref>

These characteristics result in low vibration for flat-six engines (as in [[straight-six engine]]s), especially when compared with the imbalances that are present in [[V6 engine]]s with a 90-degree bank angle.