MAHLE 3021247 Performance Steel Napier Piston Ring Set Bore - 4.055

The MAHLE 3021247 is a high-performance piston ring set engineered for precision engine builds requiring superior sealing and durability. This plain ring set features a 4.055-inch bore diameter with a steel Napier THM-13 (Tapered Hook Groove) second ring design, specifically developed for performance applications where enhanced oil control and compression sealing are critical.

Key Specifications:

• Bore Diameter: 4.055 inches
• Top Ring Width: 0.043 inch (1.09mm)
• Oil Ring Width: 0.135 inch (3.43mm)
• Ring Wall Thickness: RW (Radial Wall) design
• Design Type: Steel Napier THM-13 configuration

Performance Features:

• Steel construction provides superior strength and durability compared to traditional ductile iron rings
• Napier hook-faced second ring design delivers exceptional oil control and prevents oil buildup behind the ring
• Tapered Hook Groove (THM-13) profile creates controlled twist for optimal cylinder wall scraping during downstroke
• Engineered for reduced friction and improved ring-to-piston sealing
• Plain ring surface suited for standard cylinder bore finishes

MAHLE performance ring sets are designed using advanced simulation and computer development tools to minimize friction while maximizing sealing efficiency. The steel construction makes these rings ideal for high-performance and power-adder applications where increased strength and heat resistance are essential. This ring set is manufactured to precise tolerances ensuring proper ring loading, excellent compression retention, and effective oil control throughout the engine's operating range.