This comprehensive Sisu Diesel Engine 320, 420, 620, 634 Series Service Repair Manual provides detailed instructions and diagrams to guide you through repairs and maintenance of your engine. It covers a wide range of topics, from basic engine components like the cylinder block, crankshaft, and connecting rods to more complex systems such as the lubrication, cooling, fuel, and electrical systems. You'll find detailed information on the valve mechanism, flywheel housing, cylinder head, and timing gear assembly. The manual also includes sections on the inlet and exhaust system, counterbalance (for the 420 series), and optional equipment. With clear and concise language, high-quality illustrations, and comprehensive coverage, this manual will empower you to perform repairs confidently and efficiently, helping you save time and money.

The Sisu Diesel Engine 320, 420, 620, and 634 series represent a range of powerful and robust diesel engines manufactured by Sisu Diesel, a Finnish company renowned for its engineering expertise and commitment to durability. These engines were widely used in various heavy-duty applications, including trucks, buses, construction equipment, and marine vessels. Their reputation for reliability and longevity made them a popular choice for demanding environments and arduous tasks. The Sisu Diesel engines are known for their robust design, featuring cast-iron cylinder blocks and crankshafts, along with durable components like pistons, connecting rods, and valves. Their robust construction ensured that they could withstand the rigors of heavy-duty operation, providing long service life and minimal downtime. The engines were also characterized by their high power-to-weight ratio, contributing to their efficiency and performance across a wide range of applications. The Sisu Diesel engine series offered a range of power outputs, with the 320 series engines producing around 180 horsepower, while the 634 series models could generate over 300 horsepower. These engines were equipped with advanced features and technologies to enhance performance and fuel efficiency. Many models incorporated turbochargers to improve power output and fuel economy, while some also featured intercoolers to further increase efficiency. The engines were also designed to meet stringent emission regulations, reflecting Sisu Diesel's commitment to environmental responsibility. These features, combined with their exceptional durability and reliability, made the Sisu Diesel engine series highly sought after across various industries. However, the Sisu Diesel brand was eventually acquired by Scania, and the production of these specific engine series was discontinued. Despite their discontinuation, these engines remain a testament to Sisu Diesel's engineering excellence and continue to be valued for their performance and reliability in various applications worldwide.