King Engine Bearings MB5227XP0.25 pMax Black Race Main Bearing Set 0.25mm Undersize

The King Engine Bearings MB5227XP0.25 is a premium XP Series crankshaft main bearing set designed for Mitsubishi 4G63 and 4G64 engines (through 1992). Built to race-proven standards, this set features King's advanced pMax Black™ tri-metal construction and is precision-manufactured in a 0.25mm undersize to accommodate reground crankshafts.

pMax Black™ Technology:

• 24% greater load capacity than conventional tri-metal race bearings, with a maximum load capacity exceeding 10,200 psi
• Copper-enhanced overlay containing 5% copper, further hardened by a proprietary nano-scaled process that creates a black fatigue-resistant shield
• High-tin intermediate layer with 4.5% tin content — 22% harder than standard race bearings (115 HV) — delivering an intermediate layer load capacity of up to 17,000 psi
• SecureBond™ micro-etch surface preparation strengthens the bond between all tri-metal layers for maximum structural integrity under high loads and high RPM

XP Series Geometric Features:

• Advanced geometric design engineered specifically for forged steel aftermarket crankshafts and high-output performance applications
• Optimized oil clearance profiles to support proper oil film formation at elevated RPM and boost levels
• Precision-manufactured to tight tolerances for consistent fitment and reliable engine operation

Product Details:

• MPN: MB5227XP0.25
• Bearing Type: Main Bearing Set
• Series: XP Race Series
• Material: Tri-metal pMax Black
• Undersize: 0.25mm
• Application: Mitsubishi 4G63 and 4G64 engines through 1992

King Engine Bearings' XP Series pMax Black main bearings are the choice of professional engine builders and motorsports competitors who demand maximum durability and performance from every rebuild. Whether you're building for the strip, circuit, or rally stage, the MB5227XP0.25 delivers the load capacity and wear resistance to keep your 4G engine running strong under the most punishing conditions.