The Mercedes-Benz M104 engine, often referred to as the Mercedes V24, was a powerful and technologically advanced straight-six engine produced from 1991 to 1999. This engine powered various Mercedes-Benz models, including the W124 (300E/E320), W210 (E320), and W140 (S320) chassis. This article delves into the evolution, features, and variations of the M104, highlighting its significance in Mercedes-Benz history.
Early Version: The 3.0 Liter M104
The initial iteration of the M104 was a 3.0-liter, 24-valve engine utilizing the CIS-E (Continuous Injection System – Electronic) fuel injection system. This system, essentially a mechanically controlled injection with electronic enhancements, employed a distributor with a single coil wire and six individual spark plug wires. This version laid the groundwork for the more advanced 3.2-liter variant.
The Advanced 3.2 Liter M104
Debuting in 1993, the 3.2-liter M104 represented a significant technological leap. This engine powered U.S. models like the 300E (later corrected to E320), 300CE, 300TE, and E320. Notably, the 1993 300E models were mistakenly badged, as they actually housed the 3.2-liter engine.
A key advancement in the 3.2-liter M104 was the adoption of the HFM (Hot-Film Mass Air Flow Sensor) system with integrated electronic ignition and sequential fuel injection. This system consolidated fuel injection and ignition control into a single module. Unlike the earlier distributor-based system, the HFM setup utilized individual coil packs mounted directly onto each spark plug. Each coil pack fired two spark plugs simultaneously, using a direct connection for one and a short high-tension lead for the other, resulting in three coil wires and three high-tension leads.
The HFM system offered several advantages, including electronically controlled idle speed that couldn’t be manually adjusted. This adaptive technology compensated for factors like engine wear and unmetered intake air, ensuring consistent performance and drivability over time.
Knock Control and Variable Valve Timing
The HFM-SFI system also boasted advanced knock control capabilities. Unlike earlier EZL systems that retarded spark timing across the entire engine, the HFM system could target only the knocking cylinders, optimizing power output by maintaining the most advanced ignition timing possible.
Further enhancing performance, the 3.2-liter M104 incorporated variable valve timing on the intake camshaft. This resulted in a broader, flatter torque curve, generating horsepower at lower RPMs and providing more accessible and noticeable power delivery.
Conclusion: A Legacy of Performance
While the 3.0-liter M104 was a commendable engine, the 3.2-liter version showcased substantial advancements in fuel injection, ignition control, and variable valve timing. This made it a superior choice for performance and drivability. The Mercedes V24, embodied by the M104 engine family, remains a testament to Mercedes-Benz’s commitment to engineering excellence. Its innovative features and robust performance solidified its position as a significant engine in the brand’s history.
