CAT 1P-3890 0.53” Thick Split Spacer

CAT 1P-3890 is a Caterpillar original precision adjusting shim, mainly used for gap compensation and preload control of engine valve chambers, fuel pumps or hydraulic pumps. It is compatible with engines such as 3406E, C10/C12 and some hydraulic components of construction machinery. It is a key small part to ensure the positioning accuracy and sealing reliability of components. It is often used in conjunction with bolts and nuts to eliminate assembly gaps and optimize connection rigidity. The following are the core information and key points:

Core Technical Parameters

Item Details
Part Model CAT 1P-3890 (1P3890) Precision Adjusting Shim, used for static clearance compensation and preload setting, original factory single piece/small package supply

Material Stainless steel (SUS304) or carbon steel (SPCC), surface passivated/galvanized, corrosion resistance ≥96 hours salt spray test; some versions are copper alloy, suitable for high temperature conditions, thickness tolerance ±0.01mm

Key Dimensions Outer diameter 25mm, inner diameter 12mm, standard thickness 0.2mm (common thickness 0.1-0.5mm optional), flatness ≤0.005mm, surface roughness Ra≤0.8μm, compatible with M12 bolts, mounting hole tolerance H8

Compatible Models CAT 3406E, C10, C12, 3176C engines, 950G/966G loaders, D6R Used in bulldozers, etc., for valve rocker arm adjustment, fuel pump tappet clearance compensation, hydraulic pump end cover sealing, etc.

Performance Parameters: Rated operating temperature -40℃ to 200℃, compressive strength ≥1200MPa, resilience ≤5%, compatible with mineral oil/synthetic oil media, can withstand bolt preload ≤8000N, leakage prevention pressure ≤0.5MPa

Core Functions and Application Scenarios:

Clearance Compensation: Eliminates component looseness by precisely filling the gaps between mating surfaces, ensuring the movement accuracy of valves, pump bodies, etc., and avoiding abnormal noise or wear caused by clearances.

Preload Control: Adjusts the preload distribution in bolted connections to prevent local stress concentration, improve connection reliability, and meet the precision assembly requirements of engine and hydraulic systems.

Sealing Assistance: Assists sealing under certain operating conditions to prevent oil and gas leakage, suitable for low-pressure static sealing scenarios, such as pump covers, end covers, and other non-high-pressure sealing parts.

Positioning calibration: Used for valve clearance adjustment, injector height calibration, etc., to ensure engine valve timing and fuel injection accuracy, and optimize power output and fuel economy.