257-9166

The Caterpillar 257-9166 Inlet Valve Seat Insert is a high-temperature, precision-machined combustion chamber component. It is engineered to maintain dimensional stability, ensure airtight valve face sealing, and maximize thermal dissipation away from the intake valves during extreme internal combustion cycles subject to intense pressure and aggressive chemical exposure.

Core Dimensions & Fastener Specs
Outside Diameter (OD): 48.00 mm (1.890 in) nominal
Component Height: 12.70 mm (0.500 in)
Application Target: Cylinder head assembly (Inlet valve pocket)
Net Weight: 0.091 kg (0.201 lbs)
Material & Manufacturing Specs
Material Grade: Premium high-chromium alloy steel.
Coating & Finish: Precision casted and ground face execution with micro-polished sealing angles to minimize structural micro-pitting, carbon accumulation, and high-frequency friction wear.
Manufacturing Standards: Fully certified under ISO 9001 systems to resist thermal fatigue, structural deformation, and heavy mechanical pounding from the intake valve face.
Equipment & System Compatibility
This high-durability intake valve seat insert is standard heavy-duty hardware deployed across a vast selection of large-scale Caterpillar industrial gas engines and power generation platforms:
Engine Platforms: Deployed exclusively within the cylinder head groups of Caterpillar G3500 series large-bore industrial gas configurations, supporting G3508, G3508B, G3512, G3512B, G3516, G3516B, G3520B, and PMG3516 engine blocks.
Power Generation Systems: Widely integrated into long-run continuous generator sets, oilfield gas compression units, and localized co-generation power stations relying on the G3500 platform.
Part Cross-References
Alternative Part Names: Inlet Valve Seat Insert, Intake Valve Insert, Valve Seat Ring.
Alternative Part Numbers: 2579166, 257-9166.