King MB5243XPSTDX XP Main Bearing Set Nissan SR20DE SR20DET 2.0L STDX +Clearance

Vehicle Fitment

• Nissan 180SX (S13 chassis, SR20DET)
• Nissan 200SX (S13 / S14 chassis, SR20DE / SR20DET)
• Nissan Silvia S13 (SR20DE / SR20DET)
• Nissan Silvia S14 (SR20DE / SR20DET)
• Nissan 240SX S13 / S14 - SR20DET engine swap applications
• Nissan Sentra B13-B15 SE-R (SR20DE)
• Nissan Primera / Bluebird (SR20DE)
• Nissan Pulsar GTiR (SR20DET) - confirm compatibility; some GTiR block configurations may differ
• Any build using the Nissan SR20DE or SR20DET 16V engine with a standard-dimension crankshaft

Fitment Notes

• This set is for engines with a standard (unground) crankshaft journal diameter. The STDX suffix does not indicate an undersize for a reground crankshaft - it designates an extra-clearance shell that is 0.0005" thinner than the standard nominal, resulting in approximately 0.001" more oil clearance than a standard-size bearing on an OEM-dimension crank.
• STDX is the preferred sizing for high-performance, turbocharged, and modified SR20DET builds where additional oil clearance is desired for improved film thickness, better heat dissipation, and reduced bearing load under sustained high-RPM or high-boost operation.
• This set is NOT compatible with a reground crankshaft. For engines with an undersize crank journal, select the appropriate undersized variant (e.g., MB5243XP0.25 for a 0.25mm undergrind).
• Verify your crankshaft journal diameter with a micrometer before selecting bearing size. Consult your engine builder to confirm the correct size for your target oil clearance.
• Sold as a set of 5 pairs (10 individual shells) covering all 5 main journal positions of the SR20 block.

Features

• XP-Series tri-metal construction - the pMaxBlack™ overlay uses a proprietary nano-scaled hardening process that makes the overlay layer 24% harder than conventional tri-metal race bearings, providing industry-leading fatigue resistance and load capacity under sustained high-RPM and high-load operation.
• pMaxBlack tri-metal structure: steel backing / copper-lead intermediate layer / nickel barrier plate / lead-tin-copper Babbitt overlay - each layer bonded through King's multi-step adhesion process for superior delamination resistance and layer stability under shock loading.
• Bull's Eye Tolerance™ manufacturing - King holds wall thickness variation to ±0.0001", tighter than the industry standard of ±0.00025". All 10 shells in the set are individually matched to within this tolerance, requiring no additional sorting or selective fitting to achieve the target oil clearance.
• STDX extra-clearance sizing provides approximately 0.001" more oil clearance than a standard shell on an OEM-dimension crank, increasing oil film thickness and reducing metal-to-metal contact risk under the higher loads and temperatures generated by turbocharged, high-boost, or high-RPM SR20DET builds.
• Narrowed bearing width accommodates the large-radius crankshaft fillets common on performance and aftermarket cranks, preventing edge loading and maximizing the usable bearing surface across the journal contact area.
• Enlarged, chamfered oil holes with 3/4 groove upper shells improve oil delivery to the crankshaft journals under the higher flow demands of a performance-built engine, reducing starvation risk at high RPM.
• Medium eccentricity profile enables optimum hydrodynamic wedge formation and load distribution across the bearing surface - the same geometric principle used in King's motorsport supply work, applied to the SR20 main bearing geometry.
• Developed specifically for performance applications using forged steel aftermarket crankshafts, though equally effective on OEM cast iron crankshafts in standard-bore engine rebuilds targeting extra clearance.
• Backed by King Engine Bearings' manufacturer's warranty through authorized dealers.

Specifications

• Part Number: MB5243XPSTDX
• Engine Application: Nissan SR20DE / SR20DET 16V, 2.0L inline-4
• Bearing Type: Main bearing set (MB)
• Material Series: XP - Tri-metal copper-lead, pMaxBlack overlay
• Size: STDX (standard crankshaft journal + 0.001" extra oil clearance)
• Crankshaft Journal Diameter: 54.96-54.98mm (2.1636-2.1646 in)
• Housing Bore Diameter: 58.94-58.97mm (2.3206-2.3216 in)
• Bearing Length: 19.0mm (0.748 in)
• Wall Thickness: 1.975mm (0.0778 in)
• Groove Style: 3/4 groove upper / plain lower
• Quantity: 5 pairs (10 shells)
• Wall Thickness Tolerance: ±0.0001 in (Bull's Eye Tolerance)

Included Components

• 10x individual bearing shells (5 grooved upper / 5 plain lower) covering all 5 main journal positions

Product Description

The King MB5243XPSTDX is an XP-Series tri-metal main bearing set for the Nissan SR20DE and SR20DET 16V engine, sized in STDX - the extra-clearance designation that produces approximately 0.001" more oil film clearance than a standard-size shell on an unground OEM-dimension crankshaft. This sizing is the preferred choice among SR20DET builders working with turbocharged, high-boost, or high-RPM applications, where the additional clearance increases oil film thickness, improves hydrodynamic load capacity, and reduces the risk of bearing contact under sustained elevated cylinder pressures and journal loads. It is not a substitute for an undersize bearing on a reground crankshaft - builders should confirm crankshaft journal diameter with a micrometer and consult with their engine builder before selecting STDX over STD.

The XP-Series construction centers on King's pMaxBlack overlay, a proprietary tri-metal stack in which the Babbitt top layer undergoes a nano-scaled hardening process that makes it 24% harder than conventional race bearing overlays. This translates directly to improved fatigue resistance - the leading cause of bearing failure in high-power SR20DET builds - and a higher load capacity ceiling of 17,000psi in the intermediate layer. Bull's Eye Tolerance manufacturing holds every shell to ±0.0001" wall thickness variation, tighter than any competitor specification and tight enough that the full set can be installed directly to the builder's target clearance without selective fitting or additional sorting. The narrowed bearing width accommodates large-radius crank fillets on aftermarket forged crankshafts, and the 3/4-groove upper shells ensure consistent oil delivery at the elevated flow rates generated by high-RPM forced-induction operation.

The SR20DET engine family powers a wide range of iconic Nissan S-chassis vehicles - the S13 and S14 Silvia, 180SX, and 200SX in Japan and global markets, the Pulsar GTiR, and the Bluebird - and has become one of the most popular swap candidates worldwide for 240SX S13 and S14 builds. The naturally aspirated SR20DE shares the same main bearing geometry and is equally served by this set in performance NA builds. Sold as a set of 5 pairs covering all main journal positions.