Cylinder liner for insert casting

A cylinder liner for insert casting of a cylinder block by flowing molten metal over an outer periphery of a base of the cylinder liner, the cylinder liner including the base and a plurality of protrusions on the outer periphery of the base, wherein a distance between adjacent protrusions, an area of top portions of protrusions, and a space between the top protrusions and the outer periphery of the base are selected such that a molten metal running index YI as defined by the following Formula is 2.2 or more and 14.5 or less, wherein:

• YI=[area ratio St (%) of top portions of protrusions×molten metal infiltration volume V (mm3)/outer peripheral surface area A (mm2) of cylinder liner base]/[average surface-to-surface distance Pav (mm) between the top portions of the protrusions], the area ratio St of the top portions of the protrusions is a projected area ratio of the protrusions viewed from an outer peripheral side of the cylinder liner in a height direction of the protrusions, the molten metal infiltration volume V is represented by V=α−β−(γ×δ), where α=π×(outermost diameter dmax (mm) of the cylinder liner including the protrusions/2)2×axial length L (mm) of cylinder liner, β=π×(outer diameter d (mm) of cylinder liner base/2)2×axial length L (mm) of cylinder liner, γ=Number of protrusions per unit area×[(outer diameter d (mm) of cylinder liner base×π×axial length L (mm) of cylinder liner)/unit area (mm2)], and δ=π×(average diameter dpav (mm) of the top portions of the protrusions/2)2×average protrusion height Hav (mm), and when an end or ends of the cylinder liner is or are chamfered, the axial length L of the cylinder liner is defined as the length of the cylinder liner minus a length of chamfered portions of the end or ends of the cylinder liner.