US Patent 7293598 Cylinder liner improvements

An engine block mold, including at least one barrel slab core (10), the or each barrel slab core (10) including a slab portion (12), and at least one barrel portion (14) adapted to receive a cylinder liner (1), wherein the barrel portion (14) of the or each barrel slab core (10) has an outer diametral taper along at least a portion of its length, and the or each liner (1) has a substantially matching internal diametral taper along at least a portion of its length. Inserting the or each slab barrel core (10) with the or each liner (1) disposed upon it, into a substantially completed mold casing, filling the mold, and then machining the cylinder liners (1) so that they have a substantially constant internal diameter along their length.