King Engine Bearings MB3331SI0.5 SI-Series Main Bearing Set Subaru 1300 1600 +0.50mm Oversize

The King Engine Bearings MB3331SI0.5 is a complete main bearing set designed for Subaru 1300 and 1600 series engines. This set is offered in a +0.50mm oversize to accommodate reground or worn crankshafts, making it an ideal choice during engine rebuilds requiring journal resurfacing.

King Engine Bearings has been producing precision engine bearings since 1960, engineering products for the automotive aftermarket, aviation, and motorsports industries. The SI-Series designation indicates these bearings utilize a silicon-aluminum alloy construction — a standard aluminum-based material equivalent to SAE-783 — well-suited for low to medium load naturally aspirated engines.

Key Features:

• SI-Series silicon-aluminum alloy material — provides reliable performance for stock and mildly modified Subaru engines
• +0.50mm oversize — engineered to match crankshafts reground 0.50mm undersize
• Bull's Eye Tolerance™ technology — King's proprietary production process combining precision machining, overplating, and computerized wall thickness monitoring for minimal shell-to-shell variation
• Complete main bearing set included for full crankshaft support
• Manufactured to exacting OEM-equivalent dimensional standards
• Wide aftermarket availability in multiple undersizes and material grades

The MB3331SI0.5 is a trusted solution for engine builders performing bottom-end rebuilds on Subaru 1300 and 1600 series engines, delivering the dimensional accuracy and material quality expected from one of the industry's most respected bearing manufacturers.