CAT 5P-4309 RACE

CAT 5P-4309 is a Caterpillar original valve seat ring, which is compatible with the sealing fit between valves and cylinder heads of various diesel engines. It is used to seal the combustion chamber, conduct valve heat, and is a core wear part of the engine valve train system, ensuring compression ratio and combustion efficiency, and reducing wear on valves and cylinder heads. Here are the core information and key points:

Core Technical Parameters

Item Details
Part Model: CAT 5P-4309 (5P4309) Valve Seat Ring, original equipment manufacturer (OEM), suitable for specific engine valve positions, no universal replacement model

Material: High nickel-chromium alloy cast iron (Ni-Cr-Mo), hardness HRC 38-44, wear-resistant and heat-resistant, surface nitrided, thermal conductivity ≥45W/(m・K), temperature resistance ≥650℃

Key Dimensions: Inner diameter 45mm, outer diameter 58mm, height 12mm, chamfer r=1.5mm, taper angle 45°, interference fit 0.035-0.050mm, suitable valve stem diameter 12mm, cylinder head seat bore tolerance H7

Compatible Engines: CAT 3306, C7, C9, C13 engines, suitable for 320C/320D excavators, 966G loaders, D8R Used in bulldozers, etc., for mounting intake or exhaust valve seats.

Performance Parameters: Sealing pressure ≥10MPa, service life ≥8000 working hours, coefficient of thermal expansion 11.5×10⁻⁶/℃, valve cone surface fit ≥95%.
Core Functions and Structure:
Combustion Chamber Sealing: The cone surface fits tightly against the valve, preventing combustion gas leakage, ensuring stable engine compression ratio, and improving fuel economy and power output.

Heat Transfer: Quickly transfers heat from valve operation to the cylinder head, preventing valve overheating, deformation, or burning, and extending the service life of the valve and valve seat.

Wear Protection: High-hardness alloy material and nitrided surface resist frequent valve impacts and friction, reducing valve seat wear and maintaining sealing performance.

Precise Positioning: Interference fit installation in the cylinder head seat hole ensures coaxiality between the valve and valve seat, preventing valve wear and ensuring accurate valve timing.

Installation and Maintenance Points

Installation Specifications: Clean the cylinder head seat bores and valves to remove carbon deposits and rust. The seat bore roughness Ra ≤ 1.6μm and roundness ≤ 0.01mm. Use cold mounting (seat ring frozen to -40℃) or hot mounting (cylinder head heated to 120℃) with a special press-fit tool. Do not directly strike to prevent seat ring deformation or cracking.

After installation, ream the conical surface to ensure proper valve fit. Control valve underrun between 0.8-1.2mm to ensure sealing and heat dissipation.

Maintenance Recommendations: Check every 5000 operating hours for: wear, cracks, and dents on the sealing surface. Replace valves if leakage is observed or wear exceeds 0.2mm. When replacing valves, simultaneously check the valve conical surface; grind or replace valves if necessary.

The original 5P-4309 valve seat must be used. Ordinary valve seat can not be used as a substitute to avoid sealing failure, valve burning, and other malfunctions such as reduced engine power and increased fuel consumption due to incompatible materials, sizes, or hardness.