Repl Cyl Sleeve Honda B18 3.180 Bore 3.475 OD

The Darton Sleeves Replacement Cylinder Sleeve for Honda B18 (3.180 bore, 3.475 OD) is a precision-engineered cast iron sleeve designed for serious engine builders and performance machine shops tackling Honda B-Series block restoration and performance applications. This OEM-quality replacement sleeve restores worn cylinder bores to original specification or enables custom displacement builds in B18 engines.

Manufactured to exact tolerances with a 3.180-inch bore diameter and 3.475-inch outer diameter, this sleeve features 0.148-inch wall thickness—the engineering standard that balances structural integrity with thermal conductivity. The 5.500-inch height accommodates full deck height blocks without interference. Cast from ductile iron, Darton sleeves provide superior wear resistance and ring seal capability compared to OEM open deck designs, critical for forced-induction or high-RPM builds where bore wall degradation becomes a failure point. The precise bore geometry ensures proper ring seating and minimal blow-by across operating ranges.

This sleeve is essential for Honda B18 owners rebuilding engines after cylinder wear, coolant passage corrosion, or bore damage—and indispensable for custom B-Series displacement combinations requiring non-standard bore sizes. Installation requires honing and line-boring equipment; this is a machine shop component, not a DIY bolt-on. Each purchase includes one sleeve; quantity discounts available for complete engine builds.

Darton sleeves are recognized throughout the Honda racing and street performance community for holding bore geometry under sustained power output where cast iron blocks alone cannot. Whether you're restoring a stock B18 or building a turbocharged displacement monster, proper sleeve selection directly impacts engine longevity and reliability.