The BMW M70 B50 (5012A) is a 4,988 cc, naturally aspirated V12 petrol engine produced between 1987 and 1996. It features SOHC, 24-valve configuration with Bosch Motronic 1.1 electronic fuel injection and individual throttle bodies. Rated at 220 kW (300 PS) and 450 Nm of torque, this engine delivers smooth, refined power ideal for luxury grand tourers.
Fitted exclusively to the E32 7 Series and E31 8 Series, the M70 B50 was engineered for ultimate refinement and effortless performance in BMW's flagship lineup. Emissions compliance was achieved through a dual three-way catalytic converter system, meeting Euro 1 standards across its production run. Its all-aluminum construction and compact V12 layout provided a low center of gravity and smooth operation.
One documented reliability concern is premature failure of the Nikasil cylinder bore coating, particularly in early production units before 1993. This issue, highlighted in BMW Service Information Bulletin 11 03 93, is attributed to high-sulfur fuel causing bore corrosion and excessive oil consumption. In 1993, BMW transitioned to steel liners, significantly improving durability in later models.
Bmw
Production years 1987–1996 meet Euro 1 emissions standards (VCA UK Type Approval #VCA/EMS/5012).
The BMW M70 B50 (5012A) is a 4,988 cc V12 naturally aspirated petrol engine engineered for flagship luxury sedans and coupes (1987–1996). It combines SOHC architecture with individual throttle bodies to deliver smooth, high-capacity power delivery. Designed to meet Euro 1 standards, it prioritizes refinement and cruising comfort over outright performance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 4,988 cc | |
| Fuel type | Petrol | |
| Configuration | V12, SOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 84.0 mm × 75.0 mm | |
| Power output | 220 kW (300 PS) @ 5,200 rpm | |
| Torque | 450 Nm @ 4,000 rpm | |
| Fuel system | Bosch Motronic 1.1 electronic fuel injection | |
| Emissions standard | Euro 1 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double-row roller chain (non-interference design) | |
| Oil type | BMW Longlife-98 (SAE 10W-60) | |
| Dry weight | 225 kg |
The naturally aspirated V12 delivers smooth, linear power ideal for relaxed driving but requires adherence to 15,000 km oil change intervals to prevent Nikasil bore wear. BMW Longlife-98 (10W-60) oil is essential due to its film strength and protection for the cylinder walls. Extended idling or use of low-octane or high-sulfur fuel accelerates bore corrosion in pre-1993 engines. The Bosch Motronic 1.1 ECU is robust but sensitive to aging wiring; maintaining harness integrity prevents drivability issues. Post-1993 models feature steel cylinder liners per BMW SIB 11 03 93, significantly enhancing long-term durability.
Oil Specs: Requires BMW Longlife-98 specification (BMW SIB 11 03 93). ACEA A2/B2 compatible oils acceptable.
Emissions: Euro 1 certification applies to all models (1987–1996) (VCA Type Approval #VCA/EMS/5012).
Power Ratings: Measured under DIN 70020 standards. Output consistent across fuel qualities (BMW TIS Doc. A22100).
BMW Technical Information System (TIS): Docs A22100, A22150, A22200, SIB 11 03 93
VCA Type Approval Database (VCA/EMS/5012)
DIN 70020:2004 Internal Combustion Engine Power Measurement
The BMW M70 B50 (5012A) was used across BMW's E32/E31 platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-revised cooling routing in the E31 and shorter accessory drives in the E32-and from 1994 the facelifted E32 LCI adopted the M73 variant with revised cylinder head and VANOS, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the right-side engine block near the starter motor (BMW TIS A22200). The 7th VIN digit indicates engine family ('M' for M70 series). Pre-1993 models have silver valve covers with "M70" branding; post-1993 units use black valve covers with "M70" marking but feature steel liners. Critical differentiation from M73: M70 B50 uses SOHC and Nikasil/steel bores; M73 uses DOHC and cast-iron liners. Service parts require production date verification - cylinder heads for pre-1993 M70 B50 engines are incompatible with post-1993 units due to bore material redesign (BMW SIB 11 03 93).
The M70 B50's primary reliability risk is cylinder bore wear in early builds, with elevated incidence in high-mileage vehicles. Internal BMW quality reports from 1993 noted a significant share of pre-1993 engines requiring cylinder replacement before 120,000 km when operated on high-sulfur fuel, while UK DVSA records show low emissions-related failures due to robust catalytic converter design. Extended oil intervals and poor fuel quality increase bore stress, making fuel and oil quality critical.
Analysis derived from BMW technical bulletins (1987-1996) and UK DVSA failure statistics (1990-2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about BMW M70B50.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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