Description
CAT 1S-8560 RACE
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The CAT 1S-8560 is a genuine Caterpillar valve seat ring, compatible with the intake/exhaust valve mounting positions of 3306 and 3406 series diesel engines. It is used to seal the combustion chamber, conduct valve heat, and position the valves, ensuring stable engine compression ratio and combustion efficiency. It is a core wear component of the engine valve train system. The following are the core information and key points:
Core Technical Parameters
Item Details
Part Model CAT 1S-8560 (1S8560) Valve Seat Ring, original equipment manufacturer (OEM), available in intake/exhaust versions, non-interchangeable, no universal replacement model
Material High-nickel alloy cast iron (Ni-Resist D5S), containing 18-22% nickel and 2-3% chromium, hardness HRC 38-42, tensile strength ≥450MPa, thermal conductivity ≥45W/(m・K), heat resistance temperature ≥650℃
Key Dimensions Inner diameter 45mm, outer diameter 55mm, height 12mm, chamfer 1×45°, interference fit with cylinder head seat bore 0.015-0.025mm, suitable valve stem diameter 11mm, sealing surface cone angle 45°, runout tolerance ≤0.01mm
Compatible Engines CAT Engines in the 3306, 3406, 3406B/C, 3408, and 3412 series are used for intake/exhaust valve seats in equipment such as the 330B excavator, 980C loader, and 140G grader.
Performance Parameters: Rated sealing pressure 10MPa, applicable temperature -40℃ to 650℃, withstands valve seat impact load ≥5kN, wear life ≥10000 working hours.
Core Functions and Structure:
Sealed Combustion Chamber: Precise conical surface fits the valve to prevent gas leakage, ensuring stable engine compression ratio and power, and reducing fuel consumption.
Heat Conduction and Dissipation: High thermal conductivity alloy material quickly transfers valve heat to the cylinder head, preventing valve overheating, deformation, and erosion, extending valve life.
Positioning and Guiding: Precise inner and outer diameters and height ensure accurate valve installation positioning, preventing valve wear and jamming, and ensuring normal valve timing.
Wear-resistant and impact-resistant: High-hardness alloy material resists high-frequency valve impact and combustion gas corrosion, suitable for high-speed, high-load engine conditions.
Installation and Maintenance Points
Installation Specifications: Clean the cylinder head seat bore and seat rings to remove carbon deposits and oil stains. The seat bore roughness Ra≤1.6μm, roundness≤0.01mm; cold install the seat rings at -60℃, or hot install the cylinder head at 120℃. Do not strike the seat ring body. The rear end face of the installed seat ring should protrude 0.05-0.10mm above the cylinder head plane.
After installation, use a special tool to ream the sealing cone surface. The contact band width should be 1.2-1.5mm, the contact position should be centered, and the valve-seat ring sealing surface contact rate should be ≥90%.
Maintenance Recommendations:
Every 5000 operating hours, check the valve seat sealing surface for wear, burning, and cracks; check valve clearance for normalcy (intake 0.25-0.30mm, exhaust 0.30-0.35mm). Replace the valve seat and valves immediately if any abnormalities are found.
Genuine 1S-8560 valve seats must be used. Do not substitute with ordinary cast iron valve seats to avoid seal failure, valve burning, and reduced engine power.
