5 Engines That Run Quiet and Clean for Life and 5 That Rattle by 70,000 Miles

Honda K24 (2.4L i VTEC)

Engine performance isn’t just about horsepower or torque—it’s also about smoothness, refinement, and longevity. Some engines hum along with whisper-quiet operation and burn clean for hundreds of thousands of miles. They’re built with tight tolerances,…