This Service and Repair Manual covers International Harvester models BC144, BD144A, and BD154. These engines, known for their robust diesel power and reliable performance, are designed for demanding applications. The BC144 and BD144A feature a 144 cubic inch displacement, while the BD154 offers a slightly larger 154 cubic inch displacement, providing efficient power output and torque suitable for a variety of industrial and agricultural uses. International Harvester engines are engineered for durability and longevity, making them a trusted choice for those who require dependable operation. This comprehensive workshop manual provides essential information for maintaining and repairing your International Harvester engine. It details critical service procedures, including cylinder head and bearing installation, oil pump removal for the BC-144, and gear train timing. Troubleshooting guidance, complete with electrical system diagnostics and wiring diagrams, is included to help identify and resolve issues. Detailed engine specifications, along with hundreds of diagrams, drawings, and photos, are presented to assist owners, mechanics, and technicians in ensuring optimal performance and extending the service life of their BC144, BD144A, and BD154 engines.