Mahle 3667MS-112 Performance 1.0/1.0/2.0mm File Fit Ring Set for 3.662 in. Bore

Vehicle Fitment

• Universal - fits any performance engine with a finished bore diameter of 3.662" requiring a +.005" file fit ring set
• Suitable for V8 applications including small block and big block platforms built to a 3.662" bore specification
• Compatible with custom stroker builds, race engines, and any application requiring a 1.0mm, 1.0mm, 2.0mm ring pack at this bore size

Fitment Notes

• File fit design - rings are supplied oversize (+.005") and must be custom-gapped to the specific cylinder bore before installation
• Sold as a complete set for 8 cylinders; verify bore diameter at 0.5" below the top of the cylinder before ordering
• Not a drop-in set - end gaps must be filed to meet builder's target specifications for the intended application (street, forced induction, naturally aspirated race, etc.)
• Ring end gap must be checked and confirmed in each cylinder before installation

Features

• SAE 9254 high alloy steel top ring with patented HV385 supersonic thermal spray coating for superior bonding, scuff resistance, and increased durability under extreme heat and pressure
• Steel Napier-profile second ring acts as a check valve to relieve combustion pressure buildup beneath the top ring, improving top ring stability and reducing power loss
• MAHLE CP-20 three-piece oil control ring engineered to the specific bore diameter for optimal oil scraping, drain-back, and minimal friction
• Ultra-flat ring flanks and precision-finished faces maximize ring-to-piston groove sealing and reduce blow-by
• Low-drag 1.0mm, 1.0mm, 2.0mm ring pack reduces reciprocating mass and parasitic friction for measurable power gains
• File fit design allows builders to dial in precise end gaps for their specific application - street, boosted, or all-out race

Specifications

• Part Number: 3667MS-112
• Bore Diameter: 3.662" (File Fit - supplied at +.005" / 3.667")
• Ring Pack: 1.0mm (Top), 1.0mm (Second), 2.0mm (Oil)
• Top Ring Material: SAE 9254 high alloy steel
• Top Ring Coating: HV385 supersonic thermal spray
• Second Ring Type: Steel Napier profile
• Oil Ring Type: CP-20 three-piece assembly
• Tension: Standard tension oil control ring
• Cylinder Count: 8-cylinder set (8 complete ring sets per package)
• Fit Type: File Fit (+.005" oversize for custom gap setting)

Included Components

• 8x SAE 9254 steel HV385-coated top compression rings (1.0mm)
• 8x Steel Napier second compression rings (1.0mm)
• 8x CP-20 three-piece oil control ring assemblies (2.0mm)

Product Description

The MAHLE 3667MS-112 is a file fit performance piston ring set designed for 8-cylinder engines with a 3.662" finished bore diameter. Supplied at +.005" oversize, these rings require the builder to custom-file each ring end gap to match their specific cylinder and application - giving racers and engine builders full control over sealing performance. The ring pack features MAHLE's industry-leading 1.0mm, 1.0mm, 2.0mm configuration, which reduces reciprocating mass and minimizes friction for measurable power gains on the dyno and at the track.

The top ring is made from SAE 9254 high alloy steel and finished with MAHLE's patented HV385 supersonic thermal spray coating - a technology that combines the scuff resistance of moly-based coatings with the durability of gas nitride and PVD treatments. The steel Napier second ring functions as a check valve, venting excess combustion pressure from beneath the top ring to prevent ring float and power loss. Completing the pack is MAHLE's CP-20 oil control ring, precision-sized to the bore for maximum oil scraping efficiency and low drag. This set is built for builders who demand precision and performance in every engine they assemble.