HKS 21005-AN024 Piston Ring Set TYPE-LF N24 (d-87 mm / 4-Cylinder)

Description HKS 21005-AN024 Piston Ring Set TYPE-LF N24 (d-87 mm / 4-Cylinder)

The HKS TYPE-LF (Low Friction) piston rings used in HKS piston kits have been updated for the Ø87.0 mm model. Developed with the latest engineering principles and updated specifications, these piston rings are designed to deliver maximum performance even under demanding operating conditions.

Piston rings are one of the most important components affecting engine performance. As internal combustion engine technology continues to evolve, the materials, design, and engineering principles behind piston rings are also advancing. To incorporate these latest developments, HKS has redesigned the piston rings used in its piston kits with updated specifications. Additional sizes will be updated and released in stages.

Top Ring:

The updated top ring is designed to reduce blow-by gas under both cold and high-temperature conditions. Compared with the previous design, the gas passage area at the ring end gap has been reduced by approximately 27% at room temperature. By using a material with a higher coefficient of thermal expansion, the ring end gap is further reduced by approximately 88% under high-temperature operating conditions. Potential concerns related to the reduced passage area have also been evaluated and validated to ensure reliable performance.

The top ring also uses a new material with approximately 37% higher thermal conductivity than the previous design. This improves heat transfer from the piston and helps reduce wear in the ring grooves. Ring tension has been reduced to minimize frictional losses, while the surface treatment and coating thickness have been optimized to improve initial seating, durability, and service life.

Second Ring:

The second ring is designed to help stabilize the top ring and improve sealing performance. Its ring end gap has been increased by approximately 25%, reducing pressure in the second land area between the top and second rings. Even with the larger end gap, sealing performance is maintained because the sealing capability of the top ring has been significantly improved over the previous design.

By lowering second land pressure, the design helps suppress top ring flutter during high-speed operation. This supports stable ring movement inside the ring groove and contributes to improved sealing performance. Ring tension has also been reduced by approximately 18% compared with the previous design, helping reduce frictional losses.

Oil Ring:

The oil ring has been redesigned from the previous two-piece construction to a three-piece design. Ring tension has been reduced by approximately 10%, resulting in a significant reduction in frictional losses. Even with lower tension, the structure does not increase oil consumption, so oil control performance is maintained.

Products using piston rings:

• HKS 2103-RN025 Nickel-Plated Piston Kit SR20DET