Saab B234i Specifications
| Engine Model: Saab B234i |
| Engine Type: 4-cycle inline 4-cylinder DOHC 16-valve liquid-cooled gasoline |
| Total Displacement: 139.7 cu.in (2.29 L) |
| Rated Engine Power: 150 Hp (110 kW) at 5700 rpm |
| Fuel System Type: Bosch LH-Jetronic 2.4 electronic fuel injection |
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The Saab B234i is a 2.3-liter,
inline-four-cylinder, double overhead camshaft (DOHC), 16-valve,
naturally aspirated gasoline engine. It represents the
large-displacement, naturally aspirated variant of the B2x4 engine
family, developed as a more powerful and refined alternative to the
turbocharged models in the Saab 9000 lineup. The "i" suffix denotes fuel
injection, distinguishing it from the very early carbureted versions.
Based on the same robust cast-iron block architecture as the
turbocharged B234 engines, the B234i features a high-compression ratio,
a free-flowing aluminum 16-valve head, and Bosch LH-Jetronic fuel
injection.
It was engineered to deliver smooth, linear power and strong low-end
torque, providing a relaxed and muscular driving character suitable for
grand touring. While lacking the explosive mid-range thrust of its
turbocharged siblings, the B234i is celebrated for its mechanical
smoothness, immediate throttle response, and exceptional durability. It
is often considered one of the most reliable and understressed engines
Saab ever produced, capable of achieving extremely high mileage with
straightforward maintenance. The engine offers a uniquely "Saab"
experience: substantial, torquey, and unburstable, making it a favorite
among purists who prefer naturally aspirated performance.
Engine Family / Model: Saab B-engine series, Model B234i (Naturally
Aspirated).
Engine Type: Inline-four cylinder, transversely front-mounted,
four-stroke cycle, water-cooled, naturally aspirated gasoline engine.
Fuel Management: Bosch LH-Jetronic 2.4 electronic fuel injection.
Aspiration: Naturally aspirated.
Bore: 90.0 mm / 3.543 inches.
Stroke: 90.0 mm / 3.543 inches.
Displacement: 2,290 cc / 139.7 cubic inches.
Compression Ratio: 10.5 : 1. Firing Order: 1-3-4-2.
Rotation Direction (from front/pulley end): Clockwise.
Maximum Power Output (DIN): 110 kW (150 Hp) at 5,700 rpm.
Maximum Torque: 200 Nm (148 lb-ft) at 4,300 rpm. Redline: 6,200 rpm.
Fuel Requirement: Premium unleaded gasoline (95 RON / 91 AKI minimum).
Originally designed for leaded premium; later models were adapted for
unleaded.
Emissions Compliance: Varied by market, typically meeting early Euro 1
or US standards with a three-way catalytic converter.
Construction: Cast iron, using the same heavy-duty, deep-skirt block as
the turbocharged B234 engines. Mounted transversely and upright in the
9000 chassis. The block is massively overbuilt for naturally aspirated
duty, contributing to legendary longevity and smooth operation due to
its high mass and rigidity. Cylinder Bores: Integral (parent bore) in
the casting. Standard bore diameter is 90.00 mm (3.543 inches). The long
90mm stroke differentiates it from the 2.0L B202/B204 engines (78mm
stroke). Crankshaft: Forged steel, supported by five main bearings. Main
journal diameter is 64 mm (2.520 inches). Crankpin diameter is 58 mm
(2.283 inches).
Main Bearings: Steel-backed, tri-metal (lead-bronze) shell bearings,
known for exceptional wear resistance. Pistons: Cast aluminum alloy with
a dome or specific crown shape to achieve the 10.5:1 compression ratio.
Does not require the oil squirters used in turbocharged versions, as
thermal load is lower. Connecting Rods: Forged steel, I-beam design. Oil
Pan: Cast aluminum, structural oil pan.
Balance Shafts: Not equipped. The inherent vibration of the long-stroke
inline-four is damped by the heavy block and engine mounts.
Construction: aluminum alloy, cross-flow design. This is the same
16-valve head used on contemporary turbocharged engines, providing
excellent airflow for a naturally aspirated application.
Valve Arrangement: Double Overhead Camshafts (DOHC), driven by a toothed
timing belt. Four valves per cylinder (16-valve total).
Valvetrain: Uses mechanical bucket followers with shims for valve
clearance adjustment. This is a key difference from later hydraulic lash
adjuster (HLA) systems, requiring periodic maintenance.
Combustion Chamber: Pent-roof design with a centrally located spark
plug.
Valve Seat Angle: 45 deg. Valve Diameter: Intake: 34.0 mm (1.339
inches). Exhaust: 30.0 mm (1.181 inches). Often larger than 2.0L
variants to support greater airflow. Valve Springs: Single coil springs.
Valve Clearance (Cold): Adjusted by replacing shims located on top of
the bucket followers. Clearance: Intake: 0.20-0.30 mm (0.008-0.012
inches). Exhaust: 0.30-0.40 mm (0.012-0.016 inches). Adjustment requires
special tools and is a precise operation.
Camshaft Drive: Toothed rubber timing belt with an automatic hydraulic
tensioner and idler pulleys.
Injection System: Bosch LH-Jetronic 2.4 electronic fuel injection. This
is a speed-density system that uses a Manifold Absolute Pressure (MAP)
sensor and an air temperature sensor to calculate load, rather than an
air flow meter.
Engine Control Unit (ECU): Separate Bosch ECU for fuel management.
Ignition timing is handled by a separate Saab Direct Ignition (DI) unit
or, on earlier models, a conventional distributor.
Fuel Injectors: Electromagnetic, top-feed injectors.
Fuel Pressure Regulator: Vacuum-referenced, mounted on the fuel rail.
Maintains system pressure around 2.5 bar (36 psi). Throttle Body:
Single-bore, cable-operated.
Air Intake: Includes an idle air control valve and a MAP sensor.
Very early B234 engines (pre-1991) in some markets may have been
equipped with Bosch CIS-E mechanical injection or even carburetors, but
the B234i specifically denotes the LH-Jetronic injected version.
Type: Full-pressure, force-fed wet-sump system.
Oil Pump: Gear-type, driven by a skew gear from the crankshaft, located
in the oil pan.
Oil Filter: Cartridge-type paper element in a canister mounted on the
side of the block.
Oil Cooler: Standard equipment. An engine oil cooler (oil-to-coolant) is
fitted, a legacy of the turbo engine lineage, providing excellent oil
temperature control even under hard use.
Oil Capacity (including filter and cooler): 5.8 liters (6.1 US quarts /
5.1 Imperial quarts).
Recommended Oil Grade: API SG/SH or later. Viscosity: SAE 10W-40 or
15W-40, high-quality mineral or semi-synthetic oil is sufficient due to
lower operating temperatures compared to turbo variants.
Operating Oil Pressure: At normal operating temperature: 300-500 kPa
(3.0-5.0 bar / 44-73 psi) at 2,000 rpm. Idle pressure should be above
100 kPa (1.0 bar / 14.5 psi).
Type: Pressurized, forced circulation system.
Water Pump: Centrifugal, belt-driven from the crankshaft.
Thermostat: Wax pellet type. Opening temperature is 87°C (189°F) or 92°C
(198°F).
Radiator Pressure Cap: 100-120 kPa (1.0-1.2 bar / 14.5-17.4 psi).
Coolant Capacity (engine + radiator, approx.): 10.0 liters (10.6 US
quarts / 8.8 Imperial quarts).
Coolant Recommendation: Ethylene-glycol based antifreeze mixed with
demineralized water (50/50 ratio). Phosphate-free is recommended for
aluminum component protection.
Electrical System: 12-volt DC, negative ground. Battery in the trunk.
Ignition System: Two types exist: 1) Early models: Distributor-based
electronic ignition, with a rotor, cap, and spark plug wires. 2) Later
models: Saab Direct Ignition (DI) cassette, a block containing four
coils mounted on the valve cover.
Spark Plugs: Standard copper core or platinum plugs. Gap: 0.7-0.8 mm
(0.028-0.031 inches) for DI systems; slightly larger for distributor
systems.
Emission Controls: Varies by market. Typically includes a three-way
catalytic converter, Exhaust Gas Recirculation (EGR) valve, and
evaporative emissions (EVAP) system. Oxygen sensor(s) are used for
closed-loop fuel control. On-Board Diagnostics: Early OBD-I or
manufacturer-specific diagnostic system.
Length (from front of pulley to rear of block): 750 mm (29.5 inches).
Width (over valve cover): 750 mm (29.5 inches).
Height (from bottom of oil pan to top of intake manifold): 700 mm (27.6
inches).
Dry Weight (engine only, complete): 185-195 kg (408-430 lbs).
Engine Oil and Filter Change Interval: Every 10,000 km (6,200 miles) or
12 months. Severe service: 7,500 km (4,700 miles). The oil cooler and
large capacity promote longevity.
Spark Plugs: Replace every 20,000-30,000 km (12,400-18,600 miles) for
standard plugs. Timing Belt and Components: Replace timing belt,
hydraulic tensioner, and all idler pulleys every 80,000 km (50,000
miles) or 5 years. Failure destroys the engine.
Valve Clearance Adjustment: Essential. Check and adjust (via shim
replacement) every 40,000-50,000 km (25,000-31,000 miles). Incorrect
clearance affects performance, fuel economy, and can cause valve train
noise. Accessory Drive Belts: Inspect and adjust tension regularly.
Replace at signs of wear. Coolant Replacement: Every 2 years or 40,000
km (24,850 miles).
Fuel Filter: Replace every 40,000 km (24,850 miles). Air Filter: Replace
every 20,000-30,000 km (12,400-18,600 miles). Distributor Cap and Rotor
(if equipped): Replace every 40,000 km (24,850 miles) as part of a
standard tune-up. PCV System: Inspect and clean the oil trap ("PCV box")
every 60,000 km (37,000 miles) to ensure proper crankcase ventilation.
Cylinder Head Bolts (M12): Multi-stage torque procedure on a cold
engine. Step 1: Tighten all bolts in sequence to 50 Nm (37 lb-ft). Step
2: Tighten all bolts in sequence to 90 Nm (66 lb-ft). Step 3: Final
pass, tighten all bolts in sequence to 110 Nm (81 lb-ft). Follow the
specific Saab sequence from the center outwards. Bolts are re-usable if
not stretched.
Main Bearing Cap Bolts: 110-120 Nm (81-89 lb-ft).
Connecting Rod Cap Bolts: 65-70 Nm (48-52 lb-ft).
Flywheel to Crankshaft Bolts: 95-105 Nm (70-77 lb-ft) + 30-degree turn.
Crankshaft Pulley Bolt: 250-270 Nm (184-199 lb-ft). Requires a special
holding tool.
Camshaft Sprocket Bolts: 80-90 Nm (59-66 lb-ft).
Spark Plugs: 25-30 Nm (18-22 lb-ft).
Oil Pan Bolts: 20-25 Nm (15-18 lb-ft).
Valve Cover Bolts: 8-10 Nm (6-7 lb-ft).
Intake Manifold Bolts/Nuts: 20-25 Nm (15-18 lb-ft).
Exhaust Manifold Nuts: 30-35 Nm (22-26 lb-ft).
DI Cassette Bolts (if equipped): 8-10 Nm (6-7 lb-ft).
The Saab B234i engine was used primarily in the Saab 9000 during the
late 1980s and early 1990s as the top naturally aspirated model: Saab
9000 (1986-1993): The primary application. It powered the Saab 9000i and
9000S models. The 9000i typically denoted the fuel-injected version in
European markets, while the 9000S was often the higher trim level with
this engine in other markets. It was the flagship non-turbo engine.
This engine was not used in the Saab 900 or later 9-3/9-5 models. Its
role was specifically as a large, smooth, and reliable powerplant for
the flagship 9000 sedan and liftback, appealing to buyers who preferred
linear power delivery and potentially lower maintenance complexity
compared to the contemporary turbocharged models (B234L/E). Production
of the B234i ceased when the 9000 was facelifted in 1992 and the engine
range was rationalized, focusing more on turbocharged and later, V6
engines.
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