A liquid filter cartridge (50, 100, 170, 210, 661, 753) configured for use, in installation, in removable sealing engagement with a liquid flow collar of a liquid filter assembly; the liquid filter cartridge comprising: (a) filter media (52, 215, 681) surrounding an open filter interior (53, 215i, 682); (i) the filter media (52, 215) having first and second, opposite, ends (215u, 2151); and, defining a central axis; (b) a first end construction (64, 217, 684) positioned at the first end of the filter media (52, 215, 681); and, (c) a second end construction (65, 220, 600, 685, 773) positioned at the second end of the media; (i) the second end construction (65, 220, 600, 685, 773) being open, and including a central spigot (85, 225, 260, 601, 690, 790) projecting away from the media and surrounding and defining a central liquid flow aperture (57, 226, 688, 691) in liquid flow communication with the open filter interior (53, 215i, 682); (ii) a seal member (86, 230, 605, 693, 695, 791) positioned on the spigot (85, 225, 260, 601, 690, 790) to define a seal pattern non-orthogonal to the central axis of the media (52, 215, 681); and, (iii) a non-seal member (140, 141, 229, 700, 800) of a projection/receiver rotational alignment arrangement positioned on the second end construction at a location to engage another member of the projection/receiver rotational alignment arrangement on a liquid flow collar, in selected rotational alignment, in use, characterised in that - the non-seal member (140, 141, 229, 700, 800) of a projection/receiver arrangement on the second end construction (65, 220, 600, 685, 773) includes a first, radially outwardly projecting, interference projection (140, 141, 229, 700, 800) positioned in projection radially outwardly from an exterior surface of the central spigot (85, 225, 260, 601, 690, 790); and - the first, radially outwardly projecting, interference projection (140, 141, 229, 700, 800) defines a trapezoidally-shaped perimeter with: ( i) a base directed toward the media (52, 215, 681); ( ii) an end, opposite the base, directed toward the end tip of the central spigot (85, 225, 601, 690, 790); the end being shorter than base; and, ( iii) two, opposite, converging sides converging in extension between the base and the end. (a) filter media (52, 215, 681) surrounding an open filter interior (53, 215i, 682); (i) the filter media (52, 215) having first and second, opposite, ends (215u, 2151); and, defining a central axis; (i) the filter media (52, 215) having first and second, opposite, ends (215u, 2151); and, defining a central axis; (b) a first end construction (64, 217, 684) positioned at the first end of the filter media (52, 215, 681); and, (c) a second end construction (65, 220, 600, 685, 773) positioned at the second end of the media; (i) the second end construction (65, 220, 600, 685, 773) being open, and including a central spigot (85, 225, 260, 601, 690, 790) projecting away from the media and surrounding and defining a central liquid flow aperture (57, 226, 688, 691) in liquid flow communication with the open filter interior (53, 215i, 682); (ii) a seal member (86, 230, 605, 693, 695, 791) positioned on the spigot (85, 225, 260, 601, 690, 790) to define a seal pattern non-orthogonal to the central axis of the media (52, 215, 681); and, (iii) a non-seal member (140, 141, 229, 700, 800) of a projection/receiver rotational alignment arrangement positioned on the second end construction at a location to engage another member of the projection/receiver rotational alignment arrangement on a liquid flow collar, in selected rotational alignment, in use, (i) the second end construction (65, 220, 600, 685, 773) being open, and including a central spigot (85, 225, 260, 601, 690, 790) projecting away from the media and surrounding and defining a central liquid flow aperture (57, 226, 688, 691) in liquid flow communication with the open filter interior (53, 215i, 682); (ii) a seal member (86, 230, 605, 693, 695, 791) positioned on the spigot (85, 225, 260, 601, 690, 790) to define a seal pattern non-orthogonal to the central axis of the media (52, 215, 681); and, (iii) a non-seal member (140, 141, 229, 700, 800) of a projection/receiver rotational alignment arrangement positioned on the second end construction at a location to engage another member of the projection/receiver rotational alignment arrangement on a liquid flow collar, in selected rotational alignment, in use, - the non-seal member (140, 141, 229, 700, 800) of a projection/receiver arrangement on the second end construction (65, 220, 600, 685, 773) includes a first, radially outwardly projecting, interference projection (140, 141, 229, 700, 800) positioned in projection radially outwardly from an exterior surface of the central spigot (85, 225, 260, 601, 690, 790); and - the first, radially outwardly projecting, interference projection (140, 141, 229, 700, 800) defines a trapezoidally-shaped perimeter with: ( i) a base directed toward the media (52, 215, 681); ( ii) an end, opposite the base, directed toward the end tip of the central spigot (85, 225, 601, 690, 790); the end being shorter than base; and, ( iii) two, opposite, converging sides converging in extension between the base and the end. ( i) a base directed toward the media (52, 215, 681); ( ii) an end, opposite the base, directed toward the end tip of the central spigot (85, 225, 601, 690, 790); the end being shorter than base; and, ( iii) two, opposite, converging sides converging in extension between the base and the end.