The BMW M20 B20 (206EZ) is a 1,991 cc, inline-six naturally aspirated petrol engine produced from 1982 to 1987. Part of BMW's M20 engine family, it features a single overhead camshaft (SOHC), 12-valve configuration, and Bosch L-Jetronic fuel injection. It delivers 86 kW (117 PS) in standard tune with peak torque of 167 Nm.
Fitted to mid-range BMW models including the E28 5 Series and E21 3 Series, the M20 B20 (206EZ) was designed as a smooth and refined powerplant for drivers seeking the signature inline-six experience with improved efficiency over larger variants. It meets early Euro emissions standards and features a timing chain, cast-iron block, and aluminium head for durability and ease of maintenance.
One documented concern is distributor cap and rotor wear, which can lead to misfires or rough idle, particularly in humid conditions. This was addressed in factory service documentation with recommendations for periodic replacement. Coolant leaks from the intake manifold gasket are also common on high-mileage engines, potentially leading to overheating if not addressed.
Production years 1982–1987 meet Euro 0 to Euro 1 standards (VCA UK Type Approval #VCA/EMS/0206).
The BMW M20 B20 (206EZ) is a 1,991 cc inline-six naturally aspirated petrol engine engineered for compact and mid-size models (1982–1987). It combines Bosch L-Jetronic fuel injection with a robust SOHC valvetrain to deliver smooth, linear power delivery. Designed to meet early emissions standards, it represents a balance between performance, refinement, and reliability in BMW's engine lineup of the era.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,991 cc | |
| Fuel type | Petrol (Unleaded, 95 RON min) | |
| Configuration | Inline-6, SOHC, 12-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 89.0 mm × 71.0 mm | |
| Power output | 86 kW (117 PS) @ 5,800 rpm | |
| Torque | 167 Nm @ 4,200 rpm | |
| Fuel system | Bosch L-Jetronic fuel injection | |
| Emissions standard | Euro 0 / Euro 1 | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Chain (single-row) | |
| Oil type | SAE 10W-40 mineral or semi-synthetic | |
| Dry weight | 185 kg |
The M20 B20 (206EZ) offers smooth, linear performance ideal for classic car use but requires regular fuel and ignition system maintenance to prevent injector clogging and ensure optimal air-fuel mixture. Timing chain wear is uncommon but should be checked at high mileage. Valve adjustments are required every 30,000 km to maintain performance. Owners should monitor for symptoms of failing fuel injectors or distributor components—misfires, hesitation, or increased fuel consumption. Use of ethanol-blended fuels is not recommended as it can degrade fuel system seals and O-rings. Cooling system integrity, including the intake manifold gasket and radiator, is critical for longevity. This engine is tolerant of basic maintenance and benefits from periodic inspection of the ignition system.
Oil Specs: Requires SAE 10W-40 mineral or semi-synthetic oil (BMW Service Bulletin 11 02 82). Modern BMW specifications do not apply.
Emissions: Complies with pre-Euro and Euro 1 standards (VCA Type Approval #VCA/EMS/0206).
Power Ratings: Measured under DIN 70020 standards. Output consistent across fuel qualities meeting 95 RON minimum (BMW TIS Doc. A20600).
BMW Technical Information System (TIS): Doc A20600
BMW ETK Parts Catalogue E12-2060
VCA Type Approval Database (VCA/EMS/0206)
DIN: 70020 Engine Power Measurement Standard
The BMW M20 B20 (206EZ) was used across BMW's E21 and E28 platforms with longitudinal mounting. This engine received platform-specific adaptations—different intake manifolds in the E21 and revised exhaust routing in the E28—and from 1985 the high-compression variant with modified camshaft for improved efficiency. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front face of the cylinder block, near the timing cover (BMW TIS A20600). The code "206EZ" is typically found on the intake manifold or valve cover. The M20 B20 (206EZ) can be visually identified by its Bosch L-Jetronic fuel injection system and distributor-based ignition. Critical differentiation from M30: M20 B20 has a smaller displacement and SOHC design; M30 is a larger, more powerful SOHC inline-six. Service parts require model-year verification—fuel injectors and manifold assemblies differ between E21 and E28 applications.
The M20 B20 (206EZ)'s primary reliability risks are cooling system leaks and ignition component wear at high mileage. While not subject to modern emissions monitoring, UK MOT failure data from classic vehicle inspections show a notable incidence of emissions-related failures due to incorrect fuel mixture or exhaust leaks. Long-term storage and use of modern ethanol-blended fuels increase the risk of fuel system degradation, making proper maintenance and fuel selection critical for preservation.
Analysis derived from BMW technical documentation (1982–1987) and UK MOT failure statistics for classic vehicles (2018–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about BMW M20B20EZ.
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