The Mercedes-Benz M 102.945 is a 2,299 cc, inline-four petrol engine produced between 1980 and 1986. It features a single overhead camshaft (SOHC), 8-valve configuration, and Bosch K-Jetronic mechanical fuel injection, delivering 100 kW (136 PS) at 5,500 rpm and 196 Nm of torque at 4,000 rpm. The M 102 series was engineered for smooth refinement and durability in compact executive applications.
Fitted to models such as the W201 190 and W123 230, the M 102.945 was designed for balanced performance and reliability in urban and highway driving. It met emissions standards of its era through thermal reactor exhaust manifolds and air injection systems, allowing compliance with U.S. and European regulations without catalytic converters in early versions.
One documented concern is premature camshaft wear, particularly in engines subjected to extended oil change intervals. This issue, referenced in Mercedes-Benz Service Information Bulletin 02-85-01, is attributed to inadequate lubrication under high-load operation. In 1984, revised camshaft materials and updated oil pump calibration were introduced to improve longevity.
Production years 1980–1983 meet U.S. EPA Tier 0 and European pre-Euro standards; 1984–1986 models comply with early catalytic converter regulations (VCA UK Type Approval #VCA/EMS/2468).
The Mercedes-Benz M 102.945 is a 2,299 cc inline-four petrol engine engineered for compact and mid-size sedans (1980–1986). It combines Bosch K-Jetronic continuous fuel injection with a SOHC valvetrain to deliver smooth power delivery and long-term durability. Designed to meet early emissions standards, it balances drivability with reliability in pre-OBD automotive applications.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,299 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 96.6 mm × 78.2 mm | |
| Power output | 100 kW (136 PS) @ 5,500 rpm | |
| Torque | 196 Nm @ 4,000 rpm | |
| Fuel system | Bosch K-Jetronic mechanical fuel injection | |
| Emissions standard | Pre-Euro (U.S. EPA Tier 0, EU Step I) | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water-cooled | |
| Timing system | Single-row timing chain | |
| Oil type | SAE 10W-40 (API SF/CC) | |
| Dry weight | 158 kg |
The naturally aspirated design provides linear throttle response ideal for relaxed driving, but requires strict adherence to 10,000 km oil change intervals using SAE 10W-40 API SF/CC oil to prevent camshaft lobe wear. The Bosch K-Jetronic system is sensitive to vacuum leaks and fuel pressure inconsistencies, so regular inspection of hoses and warm-up regulator function is essential. From 1984, updated camshaft metallurgy and oil pump calibration reduced wear incidence. Engines with extended oil service intervals show elevated cam wear rates (Mercedes-Benz SIB 02-85-01). Air injection and thermal reactor systems require unmodified exhaust routing to maintain emissions compliance. Carburetor conversions are not recommended due to loss of factory calibration and emissions non-compliance.
Oil Specs: Requires SAE 10W-40 API SF/CC specification (Mercedes-Benz Service Sheet 11.02.85). Modern equivalents must meet backward compatibility.
Emissions: Pre-Euro certification applies to all models (1980–1986) (VCA Type Approval #VCA/EMS/2468). U.S. models meet EPA Tier 0 requirements.
Power Ratings: Measured under DIN 70020 standards. Output consistent across all markets with 98 RON fuel.
Mercedes-Benz Technical Information System (TIS): Docs 640.0010, M102.945
VCA Type Approval Database (VCA/EMS/2468)
Bosch Automotive Fuel Injection Handbook
The Mercedes-Benz M 102.945 was used across Mercedes-Benz's W201/W123 platforms with longitudinal mounting and rear-wheel drive layout. This engine received platform-specific adaptations-shorter intake manifolds in the W201 and revised exhaust manifolds in the W123-and from 1984 the facelifted W123 models adopted an updated camshaft design per SIB 02-85-01, creating partial interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the left-side cylinder block near the transmission bellhousing (Mercedes-Benz TIS 640.0010). The 6th and 7th digits of the VIN indicate engine type ('10' for M102-series). Pre-1984 engines have ribbed valve covers with chrome trim; post-1984 units use smooth black valve covers. Critical differentiation from M102.910: M 102.945 uses Bosch K-Jetronic injection with fuel distributor and warm-up regulator, while M102.910 uses carburetion. Service parts require production date verification—camshafts before 04/1984 are not compatible with later models due to material redesign (Mercedes-Benz SIB 02-85-01).
The M 102.945's primary reliability risk is camshaft lobe wear, with elevated incidence in vehicles with extended oil change intervals. Internal Mercedes-Benz quality reports from 1985 indicated over 12% of pre-1984 units required camshaft replacement before 120,000 km, while UK VCA emissions test data links a significant share of hydrocarbon failures to worn cam profiles in high-mileage vehicles. Infrequent oil changes and use of non-specification oil increase wear rates, making maintenance adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (1980-1986) and UK VCA failure statistics (1985-1990). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M102945.
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