Cummins Piston & Rings, .040, 4089186

replaces: 4089186, 3949844
Piston #3949844

Our pistons are manufactured from special materials like eutectic aluminum, ductile iron and steel alloy. Surface treatments such as anodizing and nitriding are typically used in the ring grooves and crown area for durability. Anti-friction coatings like tinning, phosphate and graphite provide scuff protection during initial engine break in. HDP pistons are designed and manufactured to meet or exceed the most rigorous and stringent specifications.