Balmar Serpentine Pulley Kit for Yanmar 4JH4 Series

Description

The Balmar AltMount Serpentine Pulley Conversion Kit is designed for Yanmar 4JH4-series diesel engines, including the 4JH4-HTE, 4JH4-TE, and 4JH4-DTE. It converts the accessory drive to a J10 ten-groove serpentine arrangement, increasing belt contact and load-transfer capability for high-output alternator installations.

Balmar specifically notes that the conversion can provide greater load transfer while reducing engine noise and vibration compared with an overworked conventional V-belt system. That becomes particularly important when alternator output is increased, because higher charging current requires the engine belt drive to transfer more mechanical power without slipping.

The kit includes three matching ten-groove J10 pulleys, two 46-inch-circumference J10 serpentine belts, and mounting hardware. One belt is intended for use and the second provides a ready spare. Using a matched pulley set helps maintain proper groove alignment and reduces the compromises that can result from adapting unrelated pulleys.

Balmar describes the installation as moderately simple but strongly recommends following the installation instructions closely. An AT-200A alternator may require a longer belt than the standard length included. For Yanmar 4JH4 owners upgrading to a high-output charging system, this kit provides the major drive components needed for a coordinated J10 conversion. Explore our full range of alternator mounts & pulleys.