Main Crankshaft Bearing Set for XinChai 490 / 4D27G3 Diesel Engine — XC490-4D27G3

This XC490-4D27G3 main bearing set is a complete crankshaft bearing kit precision-manufactured for the XinChai 490 and 4D27G3 diesel engines, the dominant powerplant in Heli 2-3.5 ton forklifts and numerous Chinese industrial vehicles. The main bearings are installed between the engine block main bearing saddles and the crankshaft main journals, forming the critical foundation of the entire rotating assembly. They support the crankshaft under extreme combustion loads exceeding 100 bar, maintain precise crankshaft alignment, and provide the low-friction oil-wedge surface that separates the rotating crankshaft from the stationary block. When main bearings wear beyond tolerance, you will notice dropping oil pressure, a deep rhythmic knocking from the lower engine, and eventually crankshaft journal damage that requires a complete engine rebuild — making proactive replacement at overhaul intervals a cost-effective maintenance decision.

Each bearing shell in this set is constructed using tri-metal composite technology: a high-strength steel backing for structural rigidity, an intermediate layer of copper-lead alloy for load-bearing capacity and thermal conductivity, and a precision-applied aluminum-tin overlay for superior embeddability, conformability, and corrosion resistance. The bearing backs are precision-ground to tight wall-thickness tolerances (±0.005mm) ensuring correct oil clearance without the need for line boring in most applications. An integrated oil groove and spreader channel guarantee rapid oil film formation on cold starts and maintain a full hydrodynamic oil wedge at all operating speeds, while the crush height and spread characteristics are calibrated to OE specifications for secure, rotation-free seating in the bearing saddles. Each shell undergoes 100% dimensional inspection including wall thickness mapping, crush height measurement, and surface roughness profiling before packaging.

Direct replacement for XinChai 490 and 4D27G3 engines powering Heli CPCD20-CPCD35, Hangcha CPCD20-CPCD35, Lonking LG20D-LG35D, and Tailift FD20-FD35 forklifts. Always replace main bearings as a complete set and follow the engine service manual torque sequence and specification during reassembly — typically 60-80 N·m plus angle-tightening for modern engines. Use assembly lube on bearing surfaces and pre-lube the oil system before first start. For complementary engine components, browse our forklift engine parts collection. Cross-reference engine rebuild specifications at XinChai Engine official website.

Technical Specifications

• SKU: XC490-4D27G3
• Type: Main Crankshaft Bearing Set (Complete)
• Material: Tri-Metal Composite — Steel Back + Copper-Lead Intermediate + Aluminum-Tin Overlay
• Wall Thickness Tolerance: ±0.005mm
• Fitment: XinChai 490 / 4D27G3 Diesel Engine
• Application: 2-3.5 Ton IC Forklifts (Heli, Hangcha, Lonking, Tailift)

Compatible Forklift Brands

Kingstream main bearing sets are individually wrapped in VCI (volatile corrosion inhibitor) paper, then packed in rigid compartmentalized boxes to prevent shell deformation during transit. Every batch undergoes statistical process control inspection — wall thickness mapping, crush height verification, and surface finish measurement — with full traceability to material heat lots. Standard 12-month warranty against material and manufacturing defects. Contact us for engine overhaul kit quotations, bulk pricing on bearing sets, or technical compatibility verification for your engine serial number.