CAT 4P-1635 25.4mm Outer Diameter Race

The CAT 4P-1635 is a genuine Caterpillar valve seat ring, compatible with diesel engine cylinder heads. It seals the valves against the cylinder head, withstands valve seating impact, and conducts heat. The following is precise information on the original parts:

Core Parameters and Compatibility Information

Item Details
Part Model: CAT 4P-1635 (4P1635) Genuine Valve Seat Ring, compatible with 3306 series engines, weighing approximately 0.45 kg (0.99 lb). Used in the cylinder head valve mounting position, it seals with the valve cone surface, undertaking sealing, heat conduction, and load-bearing functions.

Core Material: Cobalt-based alloy + alloy steel structure, high temperature resistance, thermal fatigue resistance, and wear resistance. Suitable for high-temperature and high-pressure exhaust valve conditions. Excellent thermal conductivity ensures thermal balance between the valve and seat ring, extending service life.

Key Dimensions: Inner diameter approx. 45.00 mm (1.772 in), outer diameter approx. 57.00 mm (2.244 in), total height approx. 12.70 mm (0.500 in), cone angle 45°, precisely fits the valve cone surface, sealing width approximately 1.5-2.0 mm, compatible with 3306 engine valve stem diameter and cylinder head mounting holes.

Structural Features: Integral ring structure, precision-machined cone surface forms a sealing band with the valve, interference fit presses into the cylinder head seat hole, precise positioning, no risk of loosening, suitable for continuous high temperature and high frequency impact conditions.

Compatible Models: Compatible with CAT 3306B/C/D industrial engines, 3306 marine engines, 3306 excavator/loader powertrains, used for exhaust valve mounting positions, often used with 107-7778 exhaust valves and 107-7779 valve guides.

Accessories: Compatible with CAT 5P-3510 seat puller, 4C-9520… The cylinder head seat ring bore tolerance (H7), valve cone contact width (1.5-2.0 mm), and surface roughness Ra≤0.8μm must be matched for installation. Core Functions and Installation Points:
* **Sealing and Heat Conduction:** Forms a sealing band with the valve cone surface to prevent combustion gas leakage; conducts valve heat to the cylinder head, preventing valve overheating and erosion, and ensuring stable engine compression ratio and power output.
* **Installation Specifications:** Clean the cylinder head seat ring bore and seat ring surface, removing carbon deposits and burrs. Check the interference fit (interference 0.05-0.10 mm) between the seat ring and the seat ring bore.
* **Cold Press into Place with a Special Stamping Tool, Ensuring Correct Cone Surface Orientation.** Do not forcefully hammer, as this may deform or damage the cylinder head.
* **After Installation:** Pair and grind with the valves. Check the continuity and sealing of the sealing band to ensure no leakage.

**Installation Specifications:** Clean the cylinder head seat ring bore and seat ring surface to remove carbon deposits and burrs. Check the interference fit (0.05-0.10 mm) for compatibility.
* **Cylinder Head Installation Specifications:** Use a special stamping tool to cold press into place, ensuring the cone surface is facing correctly. Do not hammer, as this may deform or damage the cylinder head.
* **After Installation:** Grind with the valves after installation. Check the continuity and sealing of the sealing band to ensure no leakage. Maintenance Recommendations: Inspect the valve seat wear, tapered grooves, and sealing band width every 2000-2500 operating hours. Replace with genuine parts immediately if the sealing band narrows (<1.0 mm) or shows cracks or burning.

Use only genuine CAT 4P-1635 parts to avoid valve seal failure, power loss, increased fuel consumption, and other malfunctions caused by incompatible materials/sizes.