Piston Ring Set 4.285 1.5 1.5 3.0mm

The MAHLE PISTONS Piston Ring Set 4.285 1.5 1.5 3.0mm (part number 4285MS-15) is a precision-engineered ring set designed for performance-class eight-cylinder engine rebuilds and high-output applications. This file-fit ring set features a 4.285-inch bore diameter and delivers the critical compression sealing, blow-by control, and oil management that modern engine builders demand in competition and street performance environments.

The specification breakdown—1.5mm top ring, 1.5mm second ring, and 3.0mm oil ring—represents a balanced design for 8-cylinder applications requiring standard tension characteristics. MAHLE's ductile iron construction with plasma moly coating protects ring faces during cold starts and high-load cycles while maintaining consistent wear rates across the bore. The file-fit design requires honing to the exact bore diameter for optimal piston-to-wall clearance and ring seating. This approach allows builders to dial in ring gaps and compression characteristics specific to their combustion chamber volume, fuel grade, and boost strategy.

Engine builders and machine shops selecting this ring set typically work on naturally aspirated and forced-induction V8 platforms where precision ring control directly impacts power delivery, oil consumption, and ring durability under sustained load. The 4.285-inch bore diameter places this set in the range of mid-to-large displacement eight-cylinder applications where oversized pistons address wear-related deck height issues or require custom compression ratios. Proper installation requires piston ring compressor tools, accurate bore finishing, and verification of ring end-gaps against manufacturer recommendations.