Inline-four engine
This B18 is a automobile Inline-four engine produced by Volvo from 1961 through 1968. The cam-in-block engine had overhead valves (OHV) operated by pushrods. The crankshaft rode in five main bearings, making the B18 quite different in design from its predecessor, the three-bearing B16. A larger version called the B20 appeared in 1969.