HARD BLOK WATER JACKET FILLER is a specially formulated, cement-based product with refined, size-graded iron particles combined at an optimum ratio to provide maximum strength, vibration dampening, and heat dissipation required in high performance race engines. Its coefficient of thermal expansion is identical to cast iron engine blocks. Product has been tested and proven effective in aluminum blocks.

  • Remains stable at all operating temperatures. Does not soften when exposed to high heat, nor erode under water.
  • Fills the smallest spaces in the water jacket. Does not shrink or pull away from the cylinder walls. Does not expand.
  • Extends cylinder wall life both by preventing cracked walls and by causing the walls to wear truer. Honing is minimized during rebuilds.
  • A race-proven advantage used by winners in all types of racing since 1986.
  • Non-hazardous and non-corrosive. Contains no toxic material. Once hard, it cannot be removed from the block.