An assembly comprising one or more bearing caps and a cylinder block, wherein each bearing cap comprises: receiving means for receiving a crankshaft bearing; contact means for, in use, contacting the cylinder block, and at least two projection means (22, 24) extending from the contact means for, in use, positioning the bearing cap on the cylinder block for attachment, wherein each of the projection means comprises an externally facing contact surface (26, 28) and an internally facing non-contact surface (30, 32), wherein the externally facing contact surface comprises at least a first face of the projection means which is configured to face away from the receiving means, and the internally facing non-contact surface comprises at least a second and distinct face of the projection means which is configured to face towards the receiving means, and the externally facing contact surface is dimensioned to, in use, contact a different receptacle (46, 48) of the cylinder block when positioning the bearing cap on the cylinder block for attachment, and the internally facing non-contact surface is dimensioned such that, in use, it does not contact the respective receptacle of the cylinder block when positioning the bearing cap on the cylinder block for attachment, and the externally facing contact surface comprises at least a first portion (36, 38) and second portion (52, 54) such that, for any two projection means separated by the receiving means, the separation of at least the first portion of each externally facing contact surface is smaller than the separation of outer extremities (42, 44) of the receptacles in which, in use, the projection means are received, and the separation of at least the second portion of each externally facing contact surface is larger than the separation of the outer extremities of the receptacles in which, in use, the projection means are received; and wherein the cylinder block comprises: a cylinder block contact surface for abutment to the or each contact means, and for each of the one or more bearing caps, at least two receptacles in the cylinder block contact surface, for receiving the at least two projection means extending from the contact means. receiving means for receiving a crankshaft bearing; contact means for, in use, contacting the cylinder block, and at least two projection means (22, 24) extending from the contact means for, in use, positioning the bearing cap on the cylinder block for attachment, wherein each of the projection means comprises an externally facing contact surface (26, 28) and an internally facing non-contact surface (30, 32), wherein the externally facing contact surface comprises at least a first face of the projection means which is configured to face away from the receiving means, and the internally facing non-contact surface comprises at least a second and distinct face of the projection means which is configured to face towards the receiving means, and the externally facing contact surface is dimensioned to, in use, contact a different receptacle (46, 48) of the cylinder block when positioning the bearing cap on the cylinder block for attachment, and the internally facing non-contact surface is dimensioned such that, in use, it does not contact the respective receptacle of the cylinder block when positioning the bearing cap on the cylinder block for attachment, and the externally facing contact surface comprises at least a first portion (36, 38) and second portion (52, 54) such that, for any two projection means separated by the receiving means, the separation of at least the first portion of each externally facing contact surface is smaller than the separation of outer extremities (42, 44) of the receptacles in which, in use, the projection means are received, and the separation of at least the second portion of each externally facing contact surface is larger than the separation of the outer extremities of the receptacles in which, in use, the projection means are received; and wherein the cylinder block comprises: a cylinder block contact surface for abutment to the or each contact means, and for each of the one or more bearing caps, at least two receptacles in the cylinder block contact surface, for receiving the at least two projection means extending from the contact means. a cylinder block contact surface for abutment to the or each contact means, and for each of the one or more bearing caps, at least two receptacles in the cylinder block contact surface, for receiving the at least two projection means extending from the contact means.