An engine structure for a multi-cylinder, opposed-piston engine includes a cylinder block with a plurality of inline cylinders. Each cylinder has ends with an outside diameter and an intermediate portion between the ends of a relatively larger outside diameter than the ends. The cylinder block includes a bearing web structure that positions bearing web elements outside of a plane that longitudinally bisects all of the cylinders. The cylinder block is split into two sections so as to permit cylinder liners to be inserted into and removed from cylinder tunnels in the cylinder block.