MSD 85852 Ford 351W Iron Distributor Gear with Melonite QPQ Coating

The MSD 85852 is a ductile iron distributor gear engineered specifically for Ford 351W Windsor engines. MSD invested extensive research and testing across numerous metallurgical compositions, heat treatments, and surface coatings to produce a gear that delivers long service life, a smooth break-in period, and consistent ignition timing accuracy.

At the heart of this gear is a proprietary formulated ductile iron alloy with an elevated interstitial carbide concentration, which significantly improves wear resistance and overall running characteristics. The gear receives a Melonite QPQ surface treatment — a thermochemical diffusion process that reduces friction and minimizes initial wear during the critical break-in phase. A micro-polished contact surface ensures smooth mesh engagement with the camshaft gear, reducing noise and improving rotational consistency.

Key Features:

• Proprietary formulated ductile iron construction
• Melonite QPQ coating reduces friction and initial wear
• Micro-polished surface for smooth gear contact
• Increased outer hardened layer thickness — Rockwell hardness RC 55–60
• Elevated interstitial carbide concentration for improved wear resistance
• 0.531" inner diameter (ID) for Ford 351W applications
• Roll pin included — no drilling required
• Legal for use on emissions-controlled and racing vehicles

The MSD 85852 is sold individually and is a direct-fit replacement distributor drive gear for Ford 351W Windsor engines running iron camshafts.