Piston Ring Set 4.000 Moly 5/64 5/64 3/16

The MAHLE Original Piston Ring Set 4.000 Moly 5/64 5/64 3/16 is a precision engine component engineered for eight-cylinder engines requiring a complete piston ring solution. This drop-in ring kit combines cast iron construction with plasma moly coating to deliver reliable sealing and minimal blowby across the full operating range of your engine. Manufactured to OEM specifications, this piston ring set represents the performance standard for engine rebuild and restoration work where factory-level compression retention and durability are non-negotiable.

The 4.000-inch bore diameter positions this ring set for mid-displacement eight-cylinder engines common in performance and street applications. The ring dimensions—5/64-inch compression ring thickness, 5/64-inch second compression ring thickness, and 3/16-inch oil ring thickness—are engineered to balance sealing efficiency with minimal friction losses. Plasma moly coating on the compression rings reduces wear during break-in and extends ring life by protecting against scuffing and glazing. Standard tension design ensures consistent blow-by control without excessive drag on the piston, critical for maintaining fuel economy and reducing heat generation during sustained operation.

Engine rebuild specialists and enthusiasts restoring eight-cylinder engines choose this MAHLE piston ring set when OEM-equivalent performance and durability are required. Whether rebuilding a stock engine for reliability or preparing a modified platform, the verified dimensions and proven cast iron construction with moly coating ensure consistent ring seal and minimal consumption. This is the level of precision consumers expect from MAHLE Original across automotive engine component categories.

MAHLE Original maintains strict manufacturing tolerances and material specifications across all piston ring kits. The plasma moly process adds wear protection during the critical break-in phase when ring and bore surfaces are establishing their final sealing geometry. This ring set is a complete kit—all rings required for one eight-cylinder engine—eliminating the need to source individual components from multiple suppliers.

Part number 40564CP (SKU M7740564CP) ships ready for installation, backed by MAHLE Original's reputation for precision engine components across the automotive aftermarket.