Opel B12XER Specifications
| Engine Model: Opel B12XER |
| Engine Type: 4-cycle inline 4-cylinder DOHC 16-valve liquid-cooled gasoline |
| Total Displacement: 75 cu.in (1.22 L) |
| Rated Engine Power: 70 Hp (51 kW) at 5600 rpm |
| Fuel System Type: Multi-point fuel injection |
____________________________________________________________________________________
The Opel B12XER is a 1.2-liter, naturally aspirated
inline four-cylinder gasoline engine produced from 2014 through 2019 as part of
the GM Family 0 engine architecture. The B12XER was developed as the Euro 6
emissions-compliant successor to the A12XER, incorporating internal refinements
to reduce exhaust emissions and improve fuel efficiency while maintaining the
fundamental architecture of its predecessor.
The engine’s designation reflects the transition within the Opel naming
convention, where the “B” prefix indicates the Euro 6 generation. As a member of
the Family 0 series, the B12XER shares its fundamental architecture with other
small-displacement engines in the Opel lineup, including the 1.0-liter and
1.4-liter variants, utilizing an all-aluminum construction, a timing
chain-driven valvetrain, and Double Continuous Variable Camshaft Phasing
(DC-VCP) on both intake and exhaust camshafts.
The engine was designed to meet the stringent Euro 6 emissions standards that
took effect in 2014, requiring reductions in nitrogen oxides and particulate
emissions compared to the earlier Euro 5 standards. The B12XER found its primary
applications in the Opel Corsa E and Opel Adam, serving as the entry-level
gasoline engine in these model lines.
The B12XER engine represents the final evolution of the naturally aspirated
1.2-liter engine within the GM Family 0 series before Opel’s transition to
turbocharged small-displacement engines under the PSA ownership period. The
engine’s 1,229 cc displacement is achieved through a bore of 73.4 mm and a
stroke of 72.6 mm, a configuration that is slightly oversquare compared to the
longer-stroke 1.4-liter A14XER, favoring higher engine speeds and a more
responsive character suited to the lighter Corsa and Adam platforms.
The DOHC valvetrain with 16 valves provides efficient cylinder filling, while
the DC-VCP system allows for continuous independent adjustment of intake and
exhaust camshaft timing, enabling the engine to optimize volumetric efficiency,
internal exhaust gas recirculation, and idle stability across the operating
range. The all-aluminum cylinder block and cylinder heads contribute to a dry
weight that enhances vehicle dynamics and fuel economy. The timing chain drive
eliminates scheduled replacement intervals, reducing long-term ownership costs.
The engine’s power output of 70 horsepower at 5,600 rpm and 115 Nm of torque at
4,000 rpm is modest, reflecting its positioning as an entry-level powertrain
focused on urban fuel efficiency rather than performance. The B12XER’s
refinement at idle and under light throttle is notable for a 1.2-liter
four-cylinder, with the DC-VCP system contributing to smooth operation across
the engine speed range. The engine’s Euro 6 compliance was achieved through a
combination of optimized combustion chamber design, revised catalyst
formulation, and improved engine management calibration.
Production Period: 2014-2019.
Engine Code: B12XER.
Configuration: Inline four-cylinder (I4).
Displacement: 1,229 cc (75.0 cu.in).
Bore: 73.4 mm (2.89 in).
Stroke: 72.6 mm (2.86 in).
Firing Order: 1-3-4-2.
Compression Ratio: 10.5:1.
Combustion System: Multi-point fuel injection (MPI).
Aspiration: Naturally aspirated.
Valvetrain: DOHC, 16 valves, DC-VCP (dual variable valve timing).
Maximum Engine Speed: 6,500 rpm.
Maximum Power: 70 hp (51 kW / 69 PS) @ 5,600 rpm.
Maximum Torque: 85 lb-ft (115 Nm) @ 4,000 rpm.
The B12XER cylinder block is manufactured from cast
aluminum alloy, utilizing an open-deck design at the top of the cylinder bores
to reduce weight while maintaining adequate structural integrity for naturally
aspirated operation. Cast iron cylinder liners are inserted during the casting
process, providing a durable wear surface for the piston rings and ensuring
compatibility with the aluminum pistons.
The block features a deep-skirt design that extends below the crankshaft
centerline, contributing to reduced vibration and improved main bearing
alignment. Five main bearings support the crankshaft, with the bearing caps
integrated into a structural aluminum ladder frame that also serves as the lower
crankcase. The crankshaft is constructed from cast iron, a material choice
appropriate for the engine’s power output and operating range.
The block incorporates oil galleries drilled to supply pressurized lubricant to
the crankshaft, connecting rods, and cylinder head. Oil jets are integrated into
the block, directed at the underside of the pistons to provide cooling and
reduce thermal stress. The engine’s mounting points are cast into the block to
accommodate the transverse orientation used in all applications.
The cylinder head is manufactured from cast aluminum
alloy and features a dual-overhead-camshaft (DOHC) arrangement with 16 valves.
The DC-VCP (Double Continuous Variable Camshaft Phasing) system utilizes
hydraulically actuated camshaft adjusters on both the intake and exhaust
camshafts, allowing independent timing adjustment to optimize volumetric
efficiency across the engine speed range.
The system is controlled by the engine control unit based on inputs including
engine speed, load, and coolant temperature. The valvetrain utilizes hydraulic
lash adjusters and roller finger followers, eliminating the requirement for
manual valve clearance adjustments. The intake valves measure 30.0 mm (1.18 in)
in diameter, while the exhaust valves measure 26.5 mm (1.04 in).
The combustion chamber is a pent-roof design with centrally positioned spark
plugs, optimized for flame propagation and thermal efficiency. The camshafts are
driven by a silent timing chain, with the chain routing from the crankshaft to
the exhaust camshaft and a secondary chain linking the exhaust camshaft to the
intake camshaft. The cylinder head incorporates the intake and exhaust ports on
opposite sides, with the intake ports designed to generate swirl within the
combustion chamber to enhance air-fuel mixing and combustion stability.
The fuel system utilizes multi-point fuel injection
(MPI) with a fuel injector positioned at each intake port. The system operates
at a nominal fuel pressure of 3.8 bar (55 psi), regulated by a fuel pressure
regulator mounted on the fuel rail. Fuel is delivered from an in-tank fuel pump
through a filter and to the fuel rail, which is constructed from stainless
steel. The injectors are sequentially fired by the engine control unit based on
signals from the crankshaft position sensor and camshaft position sensors.
The engine control unit calculates injector pulse width using inputs including
mass airflow, engine speed, throttle position, coolant temperature, and exhaust
oxygen sensor feedback. A hot-film mass airflow sensor is located in the intake
tract, providing precise measurement of incoming air mass. The fuel system
utilizes a returnless architecture, with the pressure regulator integrated into
the fuel pump module within the fuel tank to reduce fuel heating and evaporative
emissions, contributing to the engine’s Euro 6 compliance.
The lubrication system employs a wet-sump design with a
gear-type oil pump mounted within the front timing cover, driven directly by the
crankshaft. The pump incorporates a relief valve to maintain consistent oil
pressure across the engine speed range. Oil is drawn from the sump through a
screened pickup tube and delivered through a full-flow spin-on oil filter
mounted on the cylinder block.
The filtered oil is distributed through internal galleries to the crankshaft
main bearings, connecting rod bearings, camshaft bearings, and the hydraulic
lash adjusters. Dedicated piston cooling oil jets are supplied from the main oil
gallery, directing a stream of oil to the underside of each piston crown to
manage combustion temperatures
The DC-VCP system relies on consistent oil pressure and cleanliness for proper
operation. Total system capacity, including the filter, is 4.0 liters (4.2 qt).
The engine is specified to use low-viscosity synthetic oils, with 0W-20 grade
recommended in later applications to reduce cold-start friction and improve fuel
economy.
The cooling system is a pressurized water-cooled design
utilizing a crossflow aluminum radiator with plastic end tanks. A centrifugal
water pump, driven by the timing chain, circulates coolant through the cylinder
block, cylinder head, and radiator. The water pump is a service item with a
lifespan commensurate with the cooling system maintenance interval. A
wax-element thermostat is positioned in the coolant outlet housing, with a
nominal opening temperature of 95°C (203°F) to support thermal efficiency and
emissions compliance.
The system incorporates an expansion tank to accommodate coolant expansion and
to facilitate air removal. An electric cooling fan, controlled by the engine
control unit via a pulse-width modulated signal, provides variable airflow
across the radiator. The cooling system is designed to provide rapid warm-up to
reduce friction and fuel consumption during cold-start operation, a critical
factor for meeting Euro 6 emissions standards. Coolant capacity is 5.0 liters
(5.3 qt).
| Intake and Exhaust Systems |
Intake System: The intake system consists of an air
cleaner housing with a replaceable dry-type filter element, a hot-film mass
airflow sensor, and a two-piece intake manifold constructed from composite
plastic. The intake manifold incorporates a variable intake system with flaps
that adjust the effective runner length based on engine speed, optimizing torque
delivery across the operating range. The flaps are actuated by a vacuum-operated
diaphragm controlled by the engine control unit.
Exhaust System: The exhaust system utilizes a cast iron exhaust manifold
designed to withstand thermal cycling. The system incorporates a close-coupled
catalytic converter mounted directly to the manifold outlet, allowing the
catalyst to reach operating temperature rapidly to meet Euro 6 emissions
standards. Oxygen sensors positioned upstream and downstream of the catalyst
provide feedback for closed-loop fuel control and catalyst monitoring.
| Ignition and Electrical System |
Ignition System: The ignition system utilizes a
distributorless design with individual ignition coils mounted directly over each
spark plug in a coil-on-plug configuration. This arrangement eliminates
high-tension ignition wires, reducing electromagnetic interference and ensuring
consistent spark energy delivery. The engine control unit manages ignition
timing based on inputs including engine speed, load, knock sensor feedback, and
intake air temperature.
Electrical System: The engine is equipped with a 12-volt electrical system. The
starter motor is a reduction-gear type, sized to provide adequate cranking
torque for the 10.5:1 compression ratio. The alternator is belt-driven from the
crankshaft pulley and provides charging current for the battery and vehicle
electrical loads. The engine control unit utilizes a 32-bit processor with
integrated control for fuel injection, ignition timing, the DC-VCP system, and
the variable intake manifold flaps.
Overall Length: 610 mm (24.0 in)
Overall Width: 580 mm (22.8 in)
Overall Height: 610 mm (24.0 in)
Dry Weight (complete engine): 103 kg (227 lbs)
Engine Oil: Fully synthetic SAE 5W-30 meeting GM
dexos2, or SAE 0W-20 meeting GM dexos1 Gen 2 for improved fuel economy. Oil
Capacity (with filter change): 4.0 L (4.2 qt). Oil Change Interval: 15,000 km
(9,300 mi) or 1 year under normal conditions; 7,500 km (4,700 mi) under severe
service.
Spark Plug Type: Bosch FR7KPP33U+ or NGK equivalent. Spark Plug Gap: 0.9 mm
(0.035 in). Spark Plug Change Interval: 60,000 km (37,000 mi). Coolant Capacity:
5.0 L (5.3 qt). Coolant Specification: Phosphate-free, silicate-free antifreeze
meeting GM specification G12+ (VW TL 774-F or equivalent).
Valve Clearance: Hydraulic lash adjusters; no adjustment required. Engine Idle
Speed: 650-750 rpm. Compression Pressure: Standard: 1.2-1.4 MPa (174-203 psi);
Minimum service limit: 1.0 MPa (145 psi). Timing Chain: Chain-driven with
hydraulic tensioner; no scheduled replacement interval.
Connecting Rod Cap Bolts (M8 x 1): 20 Nm (15 lb-ft) +
90° + 90°
Main Bearing Cap Bolts (M10 x 1.25): 50 Nm (37 lb-ft) + 90° + 90°
Cylinder Head Bolts (M10, 12-point), Stage 1: 30 Nm (22 lb-ft)
Cylinder Head Bolts (M10, 12-point), Stage 2: 60 Nm (44 lb-ft) +90° + 90°
Camshaft Bearing Caps: 10 Nm (7 lb-ft) for M6
Camshaft Bearing Caps: 20 Nm (15 lb-ft) for M8
Intake Manifold to Cylinder Head: 10 Nm (7 lb-ft)
Exhaust Manifold to Cylinder Head: 20 Nm (15 lb-ft)
Flywheel/Flexplate to Crankshaft: 60 Nm (44 lb-ft) + 90° + 90°
Spark Plugs: 25 Nm (18 lb-ft)
Oil Filter Housing to Block: 25 Nm (18 lb-ft)
Water Pump Mounting: 10 Nm (7 lb-ft)
Corsa E (2014-2019): 1.2-liter naturally aspirated
variants with B12XER engine, serving as the entry-level gasoline powertrain
across European markets. Adam (2014-2019): 1.2-liter naturally aspirated
variants, positioned as the base engine option below the 1.4-liter and
turbocharged variants.
The B12XER is closely related to the A12XER (Euro 5 predecessor) and shares its
fundamental architecture with the larger-displacement A14XER. The engine was
produced at GM facilities in Europe, including the Szentgotthard plant in
Hungary.
Production of the B12XER ceased in 2019 as Opel transitioned to the new
generation of small-displacement turbocharged engines under the PSA ownership
period, including the 1.2-liter PureTech three-cylinder engine.
The B12XER was not offered in the North American market, where GM’s
small-displacement engine strategy focused on the 1.4-liter and 1.8-liter
variants. The engine’s Euro 6 compliance was achieved through a combination of
optimized combustion chamber design, revised catalyst formulation, and improved
engine management calibration, with the DC-VCP system playing a key role in
reducing cold-start emissions.
____________________________________________________________________________________
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Industrial Engines Technical Specifications |
| Outboard Engines Technical Specifications |
