Volvo B18 engine

The B18 is a 1.8 L inline four cylinder overhead valve 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 3039122 mi on its original B18 engine.

B18
The B18 is a 1.8 L overhead valve (OHV) engine with two valves per cylinder. It has five main bearings, two more than the B16.

With a bore of 84.14 mm and stroke of 80 mm, the B18 displaces 1778 cc. The cylinders are on 105 / split bore centers, where the spacing between cylinders 2 and 3 is wider than that between cylinders 1 and 2 or 3 and 4. 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 190 bhp, while a high-output version developing 225 bhp 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 suggests that the engines are for the most part separate designs.

B20
The 2 L B20 is a bored-out B18 introduced in 1969, with its bore diameter enlarged to 88.9 mm and a displacement of 1986 cc. The design is virtually identical to the earlier B18, thus most parts are functionally interchangeable, albeit with running changes to the manufacture and design of components. The B20 engine was used in the Volvo 120, 1800, 140, C202 and 240 series, and also in the Bofors Haubits FH77 howitzer. A modified version was used in the one-off 1969 Volvo GTZ concept car. The B20 was produced until 1981.

There are five variations of this engine:
 * B20A: Single carburettor version. First produced in 1969.
 * B20B: Dual carburettor version with a higher compression ratio. First produced in 1969.
 * B20D: Dual carburettor version with a lower compression ratio. First produced in 1971.
 * B20E: Fuel injection version with a high compression ratio. First produced in 1970.
 * B20F: Fuel injection version with low compression ratio. First produced in 1972 for lower emissions.

The B20E and B20F versions featured larger valves, and intake/exhaust ports and for 1974–1975 switched from electronic D-Jetronic to mechanical K-Jetronic injection.

In 1974 the number of bolts holding the flywheel increased from 6 to 8 and the size of the connecting rods was increased.

The B20A was revived for use in the C202 from 1977 to 1981.

B30
The 3.0 L six-cylinder B30 is a B20 with two additional cylinders, introduced for the 1969 model for the newly released Volvo 164.