King MB5227XP XP Main Bearing Set STD for Mitsubishi 4G63/4G64 6-Bolt 1983-1997

Vehicle Fitment

• 1983 Mitsubishi Tredia (Base, L, LS, 1.8L I4, FWD)
• 1988-1989 Mitsubishi Mirage (Turbo, 2.0L 4G63 I4, FWD)
• 1990-1994 Mitsubishi Eclipse (Base, GS, 2.0L 4G64 I4, FWD)
• 1990-1994 Mitsubishi Eclipse (GST, 2.0L 4G63T I4 Turbo, FWD)
• 1990-1994 Mitsubishi Eclipse (GSX, 2.0L 4G63T I4 Turbo, AWD)
• 1991-1992 Mitsubishi Galant (Base, GS, GSR, GSX, LS, 2.0L 4G63 I4, FWD/AWD)
• 1991-1992 Mitsubishi Galant (VR-4, 2.0L 4G63T I4 Turbo, AWD)
• 1991-1992 Mitsubishi Mirage (GS, 2.0L 4G63 I4, FWD)
• 1990-1994 Eagle Talon (Base, 2.0L 4G64 I4, FWD)
• 1993-1994 Eagle Talon (DL, ES, 2.0L 4G64 I4, FWD)
• 1995-1997 Eagle Talon (ESi, 2.0L 4G64 I4, FWD)
• 1990-1997 Eagle Talon (TSi, 2.0L 4G63T I4 Turbo, FWD/AWD)
• 1990 Plymouth Colt (GT, 2.0L 4G63 I4, FWD)
• 1990-1994 Plymouth Laser (Base, RS, 2.0L 4G63/4G64 I4, FWD/AWD)

Fitment Notes

• Fits 6-bolt crankshaft engines ONLY. Does not fit 7-bolt 4G63 engines used in mid-1992 and later DSM production, or any 2nd Generation (1995-1999) Eclipse and Talon.
• The 6-bolt to 7-bolt transition occurred mid-way through the 1992 model year; always confirm crankshaft bolt pattern before ordering.
• STD size is for use with unmachined, standard-diameter crankshaft journals only. If the crankshaft has been reground, select the appropriate undersize variant (MB5227XP010, MB5227XP020, etc.).
• 4G63 and 4G64 6-bolt main bearings share the same part number; both engines use identical main journal sizing on the 6-bolt crank platform.
• Mitsubishi Tredia (1983) fitment applies to early 4G63 pre-DSM applications; verify engine displacement and crank bolt count before installation.

Features

• pMaxBlack™ tri-metal structure with a copper-lead intermediate layer featuring 4.5% tin content - 22% harder than conventional race bearings at 115 HV, with an intermediate layer load capacity of 17,000 psi.
• pMaxBlack™ overlay uses 5% copper content with a nano-scaled hardening process, achieving 14.5 HV hardness - 24% greater fatigue resistance compared to the 11-14 HV of standard performance overlays.
• Bull's Eye Tolerance™ technology maintains wall thickness variation at ±0.0001", far tighter than the industry standard of ±0.00025", ensuring consistent oil clearance and eliminating the need to selectively fit or purchase multiple sets.
• Narrowed bearing design accommodates large-radius crankshaft fillets on the 6-bolt 4G63/4G64 crank, preventing edge stress concentration and premature fatigue failure.
• Enlarged, chamfered oil holes with 3/4 groove pattern on upper shells for improved oil film development and journal lubrication under high-RPM and high-boost conditions.
• SecureBond adhesion process delivers superior inter-layer bonding stability between the top and intermediate layers, preventing delamination under extreme thermal and mechanical cycling.
• Greater main bearing shell height improves bearing-to-bore contact area and heat transfer, reducing the risk of bearing spin at elevated RPM - critical for high-horsepower 4G63 builds.
• STD size delivers standard oil clearance directly from the box, ideal for freshly honed blocks with unmachined, standard-specification crankshaft journals.
• Race-validated construction proven in circle track, off-road, and offshore competition - designed for sustained high-load, long-duration engine operation.

Specifications

• Part Number: MB5227XP
• Bearing Type: Main bearing set (crankshaft)
• Engine Application: Mitsubishi 4G63 / 4G64 - 6-bolt crankshaft platform
• Material: Tri-metal - steel backing / copper-lead intermediate with nickel barrier / lead-tin-copper pMaxBlack™ Babbitt overlay
• Size: STD - standard journal diameter, standard oil clearance
• Wall Thickness Tolerance: ±0.0001"
• Intermediate Layer Load Capacity: 17,000 psi
• Overlay Hardness: 14.5 HV
• Groove Style: 3/4 groove (upper shells)
• Oil Hole: Enlarged and chamfered for improved flow
• Bearing Width: Narrowed for large-radius crankshaft fillets
• Position: Main (crankshaft) - journals 1 through 5

Included Components

• 5x Main bearing shells (upper and lower pairs covering all 5 main crankshaft journals)

Product Description

The King MB5227XP is a race-grade XP-Series crankshaft main bearing set purpose-built for the Mitsubishi 6-bolt 4G63 and 4G64 engine platform used across 1st Generation DSM vehicles - including the Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, Mitsubishi Galant, and early Mitsubishi Mirage and Tredia applications. Built on King's pMaxBlack™ tri-metal architecture, these bearings combine a steel backing with an elevated tin-content copper-lead intermediate layer for dramatically increased load capacity, and a nano-hardened overlay that far exceeds conventional performance bearing materials in both fatigue resistance and hardness. The STD size designation means these bearings are engineered for use with standard, unmachined crankshaft journals in freshly bored or honed blocks where no crank grinding has taken place - delivering correct oil clearance directly from the box without selective fitting or shimming.

King's narrowed bearing geometry is specifically matched to the large-radius fillet design of the 6-bolt crankshaft, eliminating the edge loading that causes premature fatigue in standard-width bearings under boost. The 3/4-grooved upper shells with enlarged, chamfered oil holes ensure a consistent, pressurized oil film across every journal surface even at high RPM and elevated boost pressure - conditions that frequently cause failures in OEM-spec or budget replacement bearings. The Bull's Eye Tolerance™ manufacturing process, which holds wall thickness variation to ±0.0001", means every shell in the set is matched to within the tightest tolerances in the industry, providing a predictable and repeatable clearance spec that serious engine builders can rely on.

It is essential to confirm your engine uses the 6-bolt crankshaft configuration before ordering. The 4G63 transitioned to a 7-bolt crankshaft design mid-production in 1992; the 7-bolt platform requires a different bearing part number. For standard journal crankshafts, the MB5227XP STD variant is the correct choice. If your crankshaft has been reground, select the matching undersize variant to suit the machined journal diameter. This set is sold as 5 shells and covers all main journal positions (1-5) on the 6-bolt 4G63/4G64 block.