The B18 is a 1.8 L inline four cylinder automobile engine produced by Volvo from 1961 through 1968. A larger 2.0 L derivative called the B20 debuted in 1969. Despite being a pushrod design, the engines can rev to 6,500 rpm. They are also reputed to be very durable. The world's highest mileage car, a 1966 Volvo P1800S, traveled more than on its original B18 engine. B18 The B18 has a single cam-in-block, operating two overhead valves (OHV) per cylinder by pushrods and rocker arms. The crankshaft rides in five main bearings, making the B18 quite different in design from its predecessor, the three-bearing B16. With a bore of and stroke of , the B18 displaces . The engine was used in Volvo's PV544, P210 Duett, 120 (Amazon), P1800 and 140 series. It could also be found in the L3314 and the Bandvagn 202 military vehicles. The B18 was fitted to many Volvo Penta sterndrive marine propulsion systems. It was also used in the Facel Vega Facel III and the Marcos 1800 GT. There are four variations of this engine: B18A: Single carburettor version. B18B: Dual carburettor version with a higher compression ratio, fitted variously with dual sidedraft SU or Zenith/Stromberg carburettors. B18C: Single carburettor version with a lower compression ratio and mechanical RPM regulator, fitted in the gasoline powered versions of the Volvo BM 320 tractor. This version was also used for the elevator in the PS-15 radar system. B18D Dual carburettor version with a lower compression ratio. DOHC In 1971 Swedish engineer Gunnar Axelsson developed a DOHC cylinder head for the B18 engine family. This cylinder head was used in competition Volvos for several years. On 1 January 2014 the Grainger & Worrall company announced that they had partnered with Axelsson to reproduce the DOHC head for the B18 engine. Power output of the base engine was expected to be , while a high-output version developing would also be available. B36 In 1952 Volvo unveiled the Volvo Philip concept car powered by a 3.6 litre V8 engine that would later be called the B36. The V8 engine had exactly the same bore and stroke dimensions as the four-cylinder B18, leading some to suggest that the B18 is one-half of the V8. Significant differences between the two engines included the fact that while the V8 engine has crossflow cylinder heads, the four cylinder has a reverse-flow cylinder head. This