Initially the overhead camshaft versions were offered as optional equipment on the 240, becoming standard in all markets by the 1976 model year.
The overhead camshaft motors were available in displacements of 2.0 (B19 and B200), 2.1 (B21), and eventually 2.3 (B23 and B230) litres.
The B21 featured an 80 mm (3.15 in) stroke, and 92 mm (3.62 in) bore.
In the US, the B21's power output ranged anywhere between 98 hp (73 kW) and 107 hp (80 kW), based on variations in the compression ratio and was typically supplied with a B or M camshaft.


The engines are tilted approx 15 degrees to left (exhaust side) to make room for the more complicated injection systems.
B19 and B21 blocks can be identified by water plugs on one side of the block.
The B23 blocks have them on both sides.
The camshaft is driven by a toothed belt that is driven off the front of the crankshaft.
The belt turns the intermediate shaft as well, which in turn drives the oil pump, distributor (on 240 engines and BXX 700/900 series engines) and the fuel pump of carburetor models.
All single camshaft versions of the engine with the exception of the K series (B200K, B230K) are of 'non-interference' design, meaning that failure of the toothed belt will not result in engine damage.

In 1981 the B21FT (a B21F with a turbo) was introduced with a compression ratio of 7.5:1 mated with a Garrett T3 turbocharger and a T camshaft.
Additional turbo variants, not offered in the US market, were the B19ET and the B21ET, based on the B19E and B21E respectively.
The turbocharger increased power output to 127 hp (95 kW) for the B21FT, and 155 hp (116 kW) for the B21ET.
6.5 psi (0.45 bar) boost on the B21FT and 9 psi (0.62 bar) boost on the B21ET.
Also new for the 1981 model year in Canada (previously introduced in 1979 outside of North America) was the B23, with a displacement of 2.3 litres (80 mm (3.15 in) stroke and 96 mm (3.78 in) bore).
Aside from the increased bore size, the engine is identical to the B21.
Volvo used a slightly different mold for the turbo engines to cast a boss for the turbo oil return line.
Because a turbocharged engine has a higher operating temperature they used sodium filled exhaust valves and a thermostat controlled oil cooler (air/oil model).

In 1983 the B23 was introduced to the United States market as a B23F engine.
Also introduced in 1983, the "intercooler boost system" (IBS) was introduced for the B21FT motors.
The IBS kit consisted of an intercooler, appropriate ducting, a new fan shroud, new oil cooler lines and mounting brackets, and optionally an automatic transmission kit.
IBS raised the output of the B21FT to 157 hp (117 kW), slightly more than the non intercooled European market B21ET's 155 hp (116 kW).
Canada also received the B21FT, along with a detuned B23E in 1983.

Midway through the 1984 model year, the "intercooler boost system" became standard on North American 240 Turbos.
Additionally a bigger clutch and a stepped flywheel were included.
Combined with changes to the fuel system in 1984 that boosted the B21FT's non-intercooled horsepower to 131 hp (98 kW), the factory intercooled 1984.5 model horsepower rating increased to 162 hp (121 kW).

In 1985 a revised, "low friction" design was introduced, dubbed the B200 and B230 (depending on displacement).
Several components had design changes, longer rods (152 mm (6.0 in) c-c, 7 mm (0.28 in) longer), pistons with a lower compression height, lower friction bearings (smaller in size), a crankshaft with 8 counterweights (instead of 4 on the older Bxx engines) and a heavy harmonic balancer (aka damper) in the crank pulley.
1989 saw an upgrade to the crankshaft, with a relocated axial thrust bearing back to the number 5 journal, bigger main bearings, rods were enlarged to 13 mm (0.51 in) from 9 mm (0.35 in) in 1990.
Also introduced in 1989 were 16 valve, twin-cam variants of the B200 and B230, dubbed the B204 and B234 respectively.
The B204 was also available in turbo form in some markets (such as Italy) where large displacement motors were taxed heavily.
It came in two versions: The B204GT turbo mot
Initially the overhead camshaft versions were offered as optional equipment on the 240, becoming standard in all markets by the 1976 model year. The overhead camshaft motors were available in displacements of 2.0 (B19 and B200), 2.1 (B21), and eventually 2.3 (B23 and B230) litres. The B21 featured an 80 mm (3.15 in) stroke, and 92 mm (3.62 in) bore. In the US, the B21's power output ranged anywhere between 98 hp (73 kW) and 107 hp (80 kW), based on variations in the compression ratio and was typically supplied with a B or M camshaft.

The engines are tilted approx 15 degrees to left (exhaust side) to make room for the more complicated injection systems. B19 and B21 blocks can be identified by water plugs on one side of the block. The B23 blocks have them on both sides. The camshaft is driven by a toothed belt that is driven off the front of the crankshaft. The belt turns the intermediate shaft as well, which in turn drives the oil pump, distributor (on 240 engines and BXX 700/900 series engines) and the fuel pump of carburetor models. All single camshaft versions of the engine with the exception of the K series (B200K, B230K) are of 'non-interference' design, meaning that failure of the toothed belt will not result in engine damage.
In 1981 the B21FT (a B21F with a turbo) was introduced with a compression ratio of 7.5:1 mated with a Garrett T3 turbocharger and a T camshaft. Additional turbo variants, not offered in the US market, were the B19ET and the B21ET, based on the B19E and B21E respectively. The turbocharger increased power output to 127 hp (95 kW) for the B21FT, and 155 hp (116 kW) for the B21ET. 6.5 psi (0.45 bar) boost on the B21FT and 9 psi (0.62 bar) boost on the B21ET. Also new for the 1981 model year in Canada (previously introduced in 1979 outside of North America) was the B23, with a displacement of 2.3 litres (80 mm (3.15 in) stroke and 96 mm (3.78 in) bore). Aside from the increased bore size, the engine is identical to the B21. Volvo used a slightly different mold for the turbo engines to cast a boss for the turbo oil return line. Because a turbocharged engine has a higher operating temperature they used sodium filled exhaust valves and a thermostat controlled oil cooler (air/oil model).
In 1983 the B23 was introduced to the United States market as a B23F engine. Also introduced in 1983, the "intercooler boost system" (IBS) was introduced for the B21FT motors. The IBS kit consisted of an intercooler, appropriate ducting, a new fan shroud, new oil cooler lines and mounting brackets, and optionally an automatic transmission kit. IBS raised the output of the B21FT to 157 hp (117 kW), slightly more than the non intercooled European market B21ET's 155 hp (116 kW). Canada also received the B21FT, along with a detuned B23E in 1983.
Midway through the 1984 model year, the "intercooler boost system" became standard on North American 240 Turbos. Additionally a bigger clutch and a stepped flywheel were included. Combined with changes to the fuel system in 1984 that boosted the B21FT's non-intercooled horsepower to 131 hp (98 kW), the factory intercooled 1984.5 model horsepower rating increased to 162 hp (121 kW).
In 1985 a revised, "low friction" design was introduced, dubbed the B200 and B230 (depending on displacement). Several components had design changes, longer rods (152 mm (6.0 in) c-c, 7 mm (0.28 in) longer), pistons with a lower compression height, lower friction bearings (smaller in size), a crankshaft with 8 counterweights (instead of 4 on the older Bxx engines) and a heavy harmonic balancer (aka damper) in the crank pulley. 1989 saw an upgrade to the crankshaft, with a relocated axial thrust bearing back to the number 5 journal, bigger main bearings, rods were enlarged to 13 mm (0.51 in) from 9 mm (0.35 in) in 1990. Also introduced in 1989 were 16 valve, twin-cam variants of the B200 and B230, dubbed the B204 and B234 respectively. The B204 was also available in turbo form in some markets (such as Italy) where large displacement motors were taxed heavily. It came in two versions: The B204GT turbo mot
Volvo Redblock Engine