So it’s de facto there are plenty of solid V-6s out there — the market ordains a high order of development. But as we’ve said for the past four years, the Mercedes-Benz unit of DaimlerChrysler AG, when it set out to develop an entirely new range of modular V-6 (and later,
V-8) engines — the first V-6s in M-B history, no less — its drivetrain boffins weren’t about to engineer anything less than a benchmark.

Never mind that the modular manufacturing plan dictated that the V-6 engines adopt the 90-degree layout ideal for V-8s; a balance shaft, rotating at twice crankshaft speed, rectified the inherent internal-balance compromise involved with V-6s using a 90-degree vee angle.

Instead, the ingenious forethought was directed at the valvetrain, where Mercedes’ new modulars were developed to employ a SOHC, 3-valve-per-cylinder design that also sports twin spark plugs. It’s an optimized emissions-reducing layout with no quarter given to requisite power/torque targets.

For the Mercedes 3.2L SOHC V-6, making the Ward’s 10 Best Engines list for the fourth consecutive year seems only to confirm the validity of the trend toward modular engine development: Mercedes now employs this engine in five of its eight vehicle lines: The big-bucks S-, SL-, CL-Class cars are the only models not to employ this versatile powerplant.

The 3.2L V-6, for example, is new to the C-Class and SLK ranges and is positively invigorating in either model. Ward’s testers continue to be amazed at how adept Mercedes has become at tailoring this engine to a wide variety of applications — a subtle talent still too rare in powertrain engineering. The 3.2L V-6 is a grunty workhorse in the M-Class SUV, a coltish-but-refined delight in the all-new C-Class and positively snappish — as well as brilliantly intake- and exhaust-sound-optimized — in its new fitment for the SLK roadster.

Strangely, though, we’ve heard that this engine range may not enjoy the longevity typical of Mercedes powertrain designs. The SOHC, 3-valve layout, at any rate, may be sacrificed when the company adopts direct injection (DI). WAW is told that DI will preclude the use of three valves and twin sparkplugs because the injector to deliver fuel directly into the combustion chamber must be vertically oriented directly in the middle of each chamber.