Editing V4 engine (section)

==Design==
Some V4 engines have two [[crankpin]]s that are shared by opposing cylinders. The crankshaft is usually supported by three [[main bearing]]s in this type of engines. However this arrangement results an uneven firing engine. Split crankpins are preferred for even firing intervals.

Compared to the more common inline-four engine layout, a V4 engine is much shorter. Although different V angles can be used, if the two pistons are at a 90° V-angle with shared crankpins, the engine also achieves a perfect [[Engine balance#Primary and secondary balance|primary balance]] and offers the additional advantage of better [[Engine balance#Primary and secondary balance|secondary balance]] that reduces vibration.<ref>{{cite web|last=Dusil |first=Tomáš |title=Automobilový vidlicový čtyřválec (V4): Proč se skoro nepoužívá? |url= http://www.auto.cz/automobilovy-vidlicovy-ctyrvalec-v4-proc-se-skoro-nepouziva-106584 |website=Auto.cz |language=cs |date=17 May 2017 |access-date=20 March 2018}}</ref> The shorter crankshaft of the V4 engine is less susceptible to the effects of [[torsional vibration]] due to its increased stiffness and also because of fewer supports suffers less friction losses.{{citation needed|date=December 2019}}

Disadvantages of V4 engines include its design being inherently wider compared to inline-4 engines, as well as the requirement of two exhaust manifolds, two-cylinder heads, and two valvetrains (thus needing two sets of camshafts for overhead cam engines) rather than only one cylinder head, one manifold, one valvetrain, and one set of camshafts for an inline-four engine.<ref>{{cite web|last=Torchinsky |first=Jason |title=Why Are V4 Engines So Rare? |url= https://jalopnik.com/why-are-v4-engines-so-rare-1792917763 |work=Jalopnik |access-date=20 March 2018}}</ref> Having two separate banks of components increases cost and complexity in comparison with inline four engines.

Because V4 engines are wider than inline-four engines, incorporating auxiliary drives, inlet systems, and exhaust systems while maintaining an overall compact size may be more difficult like other V-type engines. In order to reduce width, a narrower V-angle could be utilized, such as 60 degrees. Although a 60° V4 is more compact than a 90° V4 engine, the 60° design does not have perfect primary balance (if the crankpins are not split) and, therefore, often require a [[balance shaft]] to reduce vibrations similar to the [[V6 engine]]s. Additionally, any (four-stroke) V4 engine with shared crankpins will [[big-bang firing order|fire unevenly]] which will result in more vibration and potentially require a heavier flywheel. Using split crankpins in a 60° V4, as used on the [[Ford Essex V4 engine]] and [[Ford Taunus V4 engine]]s, results in an even firing order.