Wiseco W5161 Groove Lock Spacer 4.082-4.120in Oil Rail Support

The Wiseco W5161 Groove Lock Spacer is a precision-engineered oil rail support designed for high-performance engine builds where the piston wrist pin bore intersects the oil ring groove. Rated for bore diameters from 4.082 to 4.120 inches with a .200-inch radial wall, this spacer prevents the oil ring from protruding through the wrist pin opening during engine operation.

Key Features:

• Bore diameter range: 4.082 – 4.120 inches
• Radial wall thickness: .200 inch
• Constructed from spring steel for durability and consistent tension
• Installs against the bottom sill of the oil ring groove
• Dimple design orients end gap 90 degrees from the wrist pin for correct positioning
• Compatible only with pistons featuring an oil ring groove machined 0.030 inches wider than the oil ring

Oil rail supports are a critical component in short-compression-height applications common to high-stroke or long-rod engine builds. The W5161 is sold individually and is part of Wiseco's full lineup of groove lock spacers, engineered and manufactured at their Mentor, Ohio facility.