Wiseco S547 Unchromed Piston Pin Chromium Alloy Steel - 5115

The Wiseco S547 is an unchromed piston pin (wrist pin) manufactured from 5115 chromium alloy steel and designed for use with the CS25 spiral lock retainer. Built to Wiseco's exacting tolerances, this pin is engineered to handle the demanding forces of high-performance aftermarket engines while delivering reliable, consistent wear characteristics.

S547 Pin Specifications (5115 Material):

• Standard-grade chromium alloy steel construction
• Case hardened to 58–64 Rockwell C for excellent surface durability
• Ground to a surface finish of .15 Ra or better for precise fit and reduced friction
• Designed to withstand the normal wear and tear of a built or modified aftermarket engine
• Unchromed finish
• Compatible with CS25 spiral lock retainer

Wiseco Piston Pin Material Guide:

Wiseco offers piston pins in three material grades to match your engine's power level and application:

• 5115 Material (this pin): Standard-grade chromium alloy steel, case hardened to 58–64 Rockwell C, ground to .15 Ra or better — ideal for naturally aspirated and mildly modified engines.
• 52100 Material: High-carbon, chromium-bearing aircraft-quality alloy steel, through-hardened to 54–56 Rockwell C — engineered for high load capacity and outstanding wear and abrasion resistance.
• 9310 Material: High-quality, low-carbon case-hardened steel, hardened to 59–63 Rockwell C with a superfinish of .025 Ra or better — the top choice for turbo and nitrous applications requiring high surface strength combined with high core toughness under shock and impact loading.

The Wiseco S547 is a direct-replacement or upgrade wrist pin for use in performance piston builds. Always pair with the specified CS25 lock retainer for correct installation and retention.