Filter element with torsion lock and assembly

A liquid filter in the form of a filter element or a filter cartridge provides torsion locking relative to a filter head when the housing of such filter is threaded onto a filter head. Many embodiments employ a filter that includes a nipple portion at a top end with the torsion lock detent provided outboard of the nipple portion or integrated into the nipple portion. Many embodiments employ a simplified shoulder transition region at the top end of a torsion locked filter element. Valve actuation and/or filter differentiation is used in some embodiments. Different torsion locking arrangements, deformable thread profiles and other liquid filter features are disclosed.