Volvo B23 Specifications
| Engine Model: Volvo B23 |
| Engine Type: 4-cycle inline 4-cylinder SOHC 8-valve liquid-cooled gasoline |
| Total Displacement: 141.3 cu.in (2.31 L) |
| Rated Engine Power: 112-173 Hp (82-127 kW) at 5500 rpm |
| Fuel System Type: Carburetor or fuel injection |
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The Volvo B23 is a 2.3-liter inline-four gasoline
engine representing the "big-bore" evolution within the renowned Volvo Redblock
engine family. Produced from 1980 until 1984, this power unit served as the
premium engine option across Volvo’s rear-wheel-drive lineup during the early
1980s. It was developed to provide a significant increase in displacement and
torque over the preceding B21 series while retaining the robust architectural
principles that defined the Redblock lineage.
The B23 is distinguished by its heavy-duty internal components, including a
forged crankshaft and robust connecting rods, establishing a foundation for
durability that has made it a favored choice for high-performance and motorsport
applications despite its relatively short production run before the transition
to the B230 series.
The B23 engine is a four-stroke, spark-ignition unit defined by its oversquare
bore-to-stroke ratio. It utilizes a single overhead camshaft (SOHC) arrangement
with two valves per cylinder. The engine was produced in several distinct
variants, primarily distinguished by the fuel system and compression ratio,
which resulted in varying power outputs to suit different market demands and
vehicle applications.
Engine Type: Inline 4-cylinder, SOHC, 8 valves, gasoline
Displacement: 2.3 L; 2315 cc (141.3 cu.in)
Bore: 96.0 mm (3.78 in)
Stroke: 80.0 mm (3.15 in)
Firing Order: 1-3-4-2
Idle Speed: 850 ± 50 rpm
Valve Arrangement: 2 valves per cylinder (1 intake, 1 exhaust)
Compression Ratio
B23A (Carbureted): 10.3:1
B23E (Mechanical Fuel Injection, early): 10.0:1
B23E (Mechanical Fuel Injection, late): 10.3:1
B23ET (Turbocharged): 9.0:1
Power Output
B23A: 82 kW at 5000 rpm; 112 hp at 5000 rpm
B23E: 95-103 kW at 5400-6000 rpm; 129-140 hp at 5400-6000 rpm
B23ET: 127 kW at 5700 rpm; 173 hp at 5700 rpm
Max Torque
B23A: 185 Nm at 3500 rpm; 136 lb-ft at 3500 rpm
B23E: 190-200 Nm at 4000-4500 rpm; 140-148 lb-ft at 4000-4500 rpm
B23ET: 250 Nm at 3800 rpm; 184 lb-ft at 3800 rpm
The cylinder block is constructed from cast iron, a
defining characteristic of the Redblock engine family that contributes to its
structural rigidity and resistance to wear. This B23 variant is frequently
referred to as the "big main" block due to its substantial main bearing
dimensions, which are larger than those found in the subsequent B230 series. The
block features thick cylinder walls with a significant wall thickness, providing
a robust foundation for increased displacement and performance modifications.
The crankshaft is forged steel, offering exceptional strength for high-load
applications. Connecting rods are of the "M" designation, forged and shot-peened
for enhanced durability. Five main bearings support the crankshaft, with the
thrust bearing located at the rear of the crankshaft in this generation.
The cylinder head is manufactured from aluminum alloy
and features a single overhead camshaft design. The combustion chambers are of a
hemispherical design, which promotes efficient flame propagation. The camshaft
is driven by a rubber-toothed timing belt from the crankshaft sprocket. Valve
actuation is achieved through the camshaft acting on hydraulic or mechanical
lash adjusters, depending on the specific variant, which in turn operate the
valves via a rocker arm arrangement.
Valve Head Diameter (Intake): 44.0 mm (1.73 in)
Valve Head Diameter (Exhaust): 38.0 mm (1.50 in)
Valve Stem Diameter (Intake): 8.0 mm (0.31 in)
Valve Stem Diameter (Exhaust): 8.0 mm (0.31 in)
Camshaft Drive: Toothed timing belt
Camshaft Profiles (Variant Specific): Various profiles designated as A, H, K,
and V-cam were utilized across B23A and B23E versions, with the K-cam providing
the highest lift and duration for naturally aspirated performance. The B23ET
utilized a specific turbo-optimized camshaft profile.
The fuel system configuration varied substantially
across the B23 engine variants to suit differing performance and market
requirements.
B23A: Utilized a single downdraft Zenith-Stromberg or Solex carburetor mounted
on an aluminum intake manifold. This system employed mechanical and vacuum-based
controls for fuel delivery.
B23E: Employed the Bosch K-Jetronic continuous mechanical fuel injection system.
This system utilized a fuel distributor and airflow sensor plate to meter fuel
continuously to the injectors. The intake manifold was designed with individual
runners to optimize flow to each cylinder.
B23ET: Utilized the Bosch K-Jetronic system adapted for forced induction,
designated as K-Jetronic Turbo. This system incorporated a fuel distributor
calibrated for higher flow rates and a boost-enriched control pressure regulator
to provide additional fuel under positive manifold pressure. The intake manifold
was a cast unit designed to direct airflow from the turbocharger.
The lubrication system is a pressurized, wet-sump
design. A gear-type oil pump, driven by the crankshaft via the distributor drive
gear, draws oil from the cast aluminum oil pan. The system includes a full-flow
oil filter mounted externally on the cylinder block. Oil galleries are cast into
the cylinder block to supply the main bearings, connecting rod bearings,
camshaft bearings, and valve mechanism. The robust oil pump construction ensures
consistent oil pressure across a wide range of operating conditions.
Oil Capacity (with filter): 3.8 L (4.0 qt)
Oil Capacity (without filter): 3.5 L (3.7 qt)
Recommended Oil Grade: SAE 10W-30 or 10W-40 meeting API SF, SG, or higher
The cooling system is a pressurized system utilizing a
belt-driven water pump mounted to the front of the cylinder block. Coolant
circulation is regulated by a wax-pellet thermostat housed in a cast thermostat
housing. A cross-flow radiator with a pressure-rated cap provides primary heat
dissipation. A mechanically driven engine cooling fan with a thermostatic fan
clutch was standard, with an auxiliary electric fan employed on turbocharged
variants and vehicles equipped with air conditioning.
Coolant Capacity (total system): 7.5 L (7.9 qt)
Thermostat Opening Temperature: 87 °C (189 °F)
System Pressure Cap Rating: 75-100 kPa (0.75-1.0 bar; 11-15 psi)
Ignition System: The B23 employed a breakerless
electronic ignition system with a hall-effect sensor in the distributor. The
distributor was mounted on the side of the cylinder block and driven by a gear
from the intermediate shaft. The B23ET turbocharged variant utilized a knock
sensor and a more advanced ignition control unit to manage ignition timing under
boost conditions to prevent detonation. Spark Plug Gap: 0.70-0.80 mm
(0.028-0.031 in).
Electrical System: 12-volt with an alternator rated between 55 and 70 amperes
depending on the vehicle specification.
Exhaust System: Naturally aspirated variants utilized a cast iron exhaust
manifold. The B23ET featured a specific high-flow cast iron exhaust manifold
designed to direct exhaust gases to the turbocharger, a Garrett T3 unit, which
was integrated into the exhaust system.
Overall Length: 760 mm (29.9 in)
Overall Width: 570 mm (22.4 in)
Overall Height: 690 mm (27.2 in)
Dry Weight (without fluids): 165 kg (364 lb)
Valve Clearance: Mechanical valve lash adjusters (on
early and high-performance variants) require inspection; clearance: intake
0.35-0.45 mm (0.014-0.018 in) cold; exhaust 0.40-0.50 mm (0.016-0.020 in) cold.
Hydraulic lash adjusters (on later variants) require no adjustment. Timing Belt
Replacement Interval: 80,000 km (50,000 mi) for B23E and B23ET; 50,000 km
(31,000 mi) for B23A in some markets.
Engine Oil and Filter: Replacement interval of 6 months or 7,500 km (4,700 mi)
under normal conditions. Spark Plugs: Replacement interval of 30,000 km (18,600
mi). Air Filter Element: Replacement interval of 30,000 km (18,600 mi). Coolant:
Replacement interval of 2 years. Drive Belts (Accessory): Inspect every 7,500 km
(4,700 mi); replace if cracking or glazing is evident.
Cylinder Head Bolts: 30 Nm (22 lb-ft) plus
angle-tighten 90 deg.
Main Bearing Cap Bolts: 100 Nm (74 lb-ft).
Connecting Rod Cap Bolts: 55 Nm (41 lb-ft) plus angle-tighten 90 deg.
Camshaft Bearing Cap Bolts: 20 Nm (15 lb-ft).
Flywheel / Drive Plate Bolts: 55 Nm (41 lb-ft) plus angle-tighten 90 deg.
Spark Plugs: 25 Nm (18 lb-ft).
Oil Pan Bolts: 10 Nm (7 lb-ft).
Water Pump Bolts: 20 Nm (15 lb-ft).
Timing Belt Tensioner Bolt: 25 Nm (18 lb-ft).
The Volvo B23 engine served as the premier powerplant
across several Volvo rear-wheel-drive models during its production years,
frequently designated in GLT (Grand Luxe Touring) and GLE trim levels to denote
the enhanced performance specification.
1980-1984 Volvo 240 Series (242, 244, 245): Utilized B23A, B23E, and in some
markets, the B23ET.
1984 Volvo 740: Early production models utilized the B23E and B23ET before the
transition to the B230 series.
1982-1984 Volvo 760 Turbo: Exclusively utilized the B23ET during the model’s
debut years, providing the flagship sedan and estate with forced-induction
performance.
1980-1984 Volvo 260 Series: Select markets received B23-based variants in place
of the PRV V6 engine.
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