Editing Camshaft (section)

==== Lift ====
The camshaft's lift determines the distance between the valve and the [[valve seat]] (i.e. how far open the valve is).<ref name="summitracing.com lift">{{cite web |title=Camshaft Lift |url=https://help.summitracing.com/app/answers/detail/a_id/4699/ |website=www.summitracing.com}}</ref> The farther the valve rises from its seat the more airflow can be provided, thus increasing the power produced. Higher valve lift can have the same effect of increasing peak power as increased duration, without the downsides caused by increased valve overlap. Most overhead valve engines have a rocker ratio of greater than one, therefore the distance that the valve opens (the ''valve lift'') is greater than the distance from the peak of the camshaft's lobe to the base circle (the ''camshaft lift'').<ref name="hotrod.com camshaft basics">{{cite web |title=Be The Camshaft Expert |url=https://www.hotrod.com/articles/0607phr-camshaft-basics/ |website=www.hotrod.com |access-date=18 July 2020 |language=en |date=14 June 2006}}</ref>

There are several factors which limit the maximum amount of lift possible for a given engine. Firstly, increasing lift brings the valves closer to the piston, so excessive lift could cause the valves to get struck and damaged by the piston.<ref name="jegs.com"/> Secondly, increased lift means a steeper camshaft profile is required, which increases the forces needed to open the valve.<ref name="summitracing.com lift"/> A related issue is ''valve float'' at high RPM, where the spring tension does not provide sufficient force to either keep the valve following the cam at its apex or prevent the valve from bouncing when it returns to the valve seat.<ref name="summitracing.com valve float">{{cite web |title=What is valve float? |url=https://help.summitracing.com/app/answers/detail/a_id/4765/kw/float |website=www.summitracing.com |access-date=18 July 2020}}</ref> This could be a result of a very steep rise of the lobe,<ref name="jegs.com"/> where the cam follower separates from the cam lobe (due to the valvetrain inertia being greater than the closing force of the valve spring), leaving the valve open for longer than intended. Valve float causes a loss of power at high RPM and in extreme situations can result in a bent valve if it gets struck by the piston.<ref name="hotrod.com camshaft basics"/><ref name="summitracing.com valve float"/>