Wiseco GLS21 Dimpled Oil Rail Support for 3.382–3.434 in. Bore Pistons

The Wiseco GLS21 Dimpled Oil Rail Support is an essential piston component designed for performance engine builds where the piston oil ring groove intersects the wrist pin bore. Without proper support in these applications, the oil ring rails can protrude into the pin opening — the GLS21 prevents this by bridging the gap and maintaining consistent ring contact around the full bore circumference.

Key Features:

• Bore Range: Fits 3.382 in. to 3.434 in. bore pistons
• Dimpled Design: Special anti-rotation dimple keeps the support indexed directly in line with the piston pin for proper alignment
• Spring Steel Construction: Manufactured from spring steel for durability and consistent tension throughout the engine's operating range
• Precise Fit: Features a 0.140 in. radial wall; compatible only with pistons where the oil ring groove is machined 0.030 in. wider than the oil ring
• Sold Individually: One (1) oil rail support per package
• USA Manufactured: Engineered and machined at Wiseco's Mentor, Ohio facility

Wiseco GLS21 oil rail supports are a critical component in short-compression-height piston applications — common in high-stroke or long-rod engine builds — where the pin bore breaks through the oil groove. The GLS21 installs against the bottom sill of the oil ring groove, ensuring the oil rails remain properly supported and the piston operates smoothly across the entire RPM range. Always confirm piston groove dimensions before ordering.