Cummins / Cummins B series engines (B3.9 / B4.5 / B5.9 / B6.7) are the most successful in terms of reliability and simplicity. That is why their population is the most numerous in comparison with other series of engines of this company. This series of engines of the Cummins Corporation / Cummins has several modifications, dividing the engines by displacement. In the arsenal of this series (series B) there are engines with a volume of 3.9 liters (Cummins B3.9), 5.9 liters (Cummins B5.9), 4.5 liters (B4.5), 6.7 liters (B6. 7). It is worth noting that the motors of this series are available in four-cylinder and six-cylinder versions.