The Mercedes-Benz M110.922 is a 2,746 cc, inline-six petrol engine produced between 1973 and 1986. It features a single overhead camshaft (SOHC) design with two valves per cylinder and mechanical fuel injection (K-Jetronic). Rated at 125 kW (170 PS) and 240 Nm of torque, it delivers smooth power delivery and refined operation for executive saloons of the era.
Fitted to models such as the W114 280, W115 280C, and W123 280E, the M110.922 was engineered for balanced driving dynamics, combining responsive throttle response with long-distance comfort. Emissions compliance was achieved through exhaust gas recirculation (EGR) and catalytic converter systems, meeting pre-Euro and early Euro standards depending on model year and market.
One documented service concern is premature wear of the mechanical fuel injection plunger unit, which can lead to uneven fuel distribution and misfires. This issue, referenced in Mercedes-Benz Service Information Bulletin 07-58-01, is attributed to fuel quality sensitivity and extended service intervals. Later production revisions included updated sealing materials and improved flow calibration to enhance durability.
Production years 1973–1980 meet pre-Euro standards; 1981–1986 models comply with Euro 1 (VCA UK Type Approval #VCA/EMS/5684).
The Mercedes-Benz M110.922 is a 2,746 cc inline-six petrol engine designed for executive saloons and coupes (1973–1986). It combines SOHC architecture with Bosch K-Jetronic continuous fuel injection to deliver smooth power delivery and high-speed refinement. Engineered during a period of increasing emissions regulation, it balances performance with early emission control requirements.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,746 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-6, SOHC, 12-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 87.0 mm × 76.5 mm | |
| Power output | 125 kW (170 PS) | |
| Torque | 240 Nm @ 3,750 rpm | |
| Fuel system | Bosch K-Jetronic (mechanical continuous injection) | |
| Emissions standard | Pre-Euro (1973–1980); Euro 1 (1981–1986) | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Single-row timing chain (non-interference design) | |
| Oil type | SAE 20W-50, API SE/SF | |
| Dry weight | 178 kg |
The naturally aspirated SOHC design provides smooth mid-range power ideal for highway cruising but requires strict adherence to 15,000 km oil change intervals to prevent fuel injection wear and camshaft degradation. SAE 20W-50 oil meeting API SE/SF specifications is essential due to its thermal stability under sustained load. Extended idling or aggressive driving without warm-up increases wear on the injection plunger unit. The K-Jetronic system demands clean, high-octane fuel and regular inspection of air flow sensors to maintain injector performance. Post-1981 models feature revised fuel head design; pre-1981 units benefit from inspection per Mercedes-Benz SIB 07-58-01. Lambda sensor and catalytic converter health must be monitored to maintain emissions compliance and prevent drivability issues.
Oil Specs: Requires SAE 20W-50, API SE/SF specification (Mercedes-Benz SIB 07-58-01). Compatible with ACEA A2-89.
Emissions: Euro 1 certification applies to 1981–1986 models only (VCA Type Approval #VCA/EMS/5684). Pre-1981 models meet national type approvals under EU Directive 70/220/EEC.
Power Ratings: Measured under DIN 70020 standards. Output consistent across model applications (Mercedes-Benz TIS Doc. A35140).
Mercedes-Benz Technical Information System (TIS): Docs A34760, A35140, SIB 07-58-01
VCA Type Approval Database (VCA/EMS/5684)
ISO 1585:1992 Road vehicles — Engine test code — Net power
The Mercedes-Benz M110.922 was used across Mercedes-Benz's W114/W115/W123 platforms with longitudinal mounting and no licensing partnerships. This engine received platform-specific adaptations-revised intake manifolds in the W114 and modified exhaust routing in the W123-and from 1981 the updated W123 models adopted Euro 1-compliant variants with enhanced lambda control, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-facing side of the cylinder block, near the exhaust manifold (Mercedes-Benz TIS A34840). The 8th VIN digit indicates engine type ('M' for M110 series). Pre-1981 models feature analog K-Jetronic with mechanical fuel distributor; post-1981 units use updated K-Jetronic with lambda feedback. Critical differentiation from M110.921: M110.922 has a 2,746 cc displacement and 170 PS output. Service parts require model-year verification—fuel heads and ECUs for pre-1981 models are not interchangeable with Euro 1 variants due to emissions revisions (Mercedes-Benz SIB 07-58-01).
The M110.922's primary reliability risk is mechanical fuel injection wear on pre-1981 builds, with elevated incidence in high-mileage urban use. Internal Mercedes quality reports from 1982 indicated a notable share of engines requiring fuel head replacement before 150,000 km, while VCA field data links a significant portion of emissions-related failures to lambda sensor degradation in city-driven vehicles. Extended oil intervals and use of non-specified oils increase plunger and camshaft stress, making oil quality and service adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (1973-1986) and UK VCA failure statistics (1980-1995). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M110922.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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