CAT 2H-7878 Sleeve Bearing

CAT 2H-7878 is a Caterpillar genuine steel-backed aluminum-based camshaft sleeve bearing (shield), suitable for camshaft support in 3406 series diesel engines. It is used to position the camshaft, reduce friction and axial movement. The following are precise original part information:

Core Technical Parameters
Item Details
Part Model: CAT 2H-7878 (2H7878) Camshaft Sleeve Bearing (Shield), weight approximately 0.12 kg (0.26 lb), suitable for camshaft intermediate journal support in 3406B/3406C/3406E engines

Core Material: Steel backing + aluminum-based alloy (Al-Sn-Si) anti-friction layer. Steel backing hardness HB 180-220, aluminum-based alloy layer thickness 0.3-0.5 mm. Suitable for high-temperature, high-lubrication conditions in engines, wear-resistant and anti-seize.

Key Dimensions: Inner diameter 76.2 mm (3.00 in), outer diameter 85.73 mm 3.375 in diameter and 50.8 mm (2.00 in) width, this is a split 17A structure with a locating lip, suitable for mounting camshaft intermediate journals.

Structural Features: Split design for easy installation and replacement; locating lip prevents rotation; aluminum-based alloy layer provides self-lubrication, suitable for low-to-medium speed and alternating load conditions, ensuring stable operation of the valve train.

Compatible Models: Compatible with CAT 3406B/3406C/3406E diesel engines (camshaft intermediate bearing), and compatible with 3406 series engines in loaders (980F/988F), bulldozers (D8L/D9N), mining trucks (777B), and other equipment.

Accessories: Compatible with camshaft intermediate journals (76.2 mm diameter); compatible installation tools: CAT 1U-7360 bearing puller, 2S-8359. When installing the sleeve, it is recommended to simultaneously check the camshaft journal wear and coaxiality.

Core Functions and Installation Points

Camshaft Positioning and Friction Reduction: Used for supporting the intermediate journal of the camshaft, positioning the camshaft, reducing friction between the journal and the cylinder block, bearing radial loads and slight axial thrust, ensuring accurate valve timing and stable operation.

Installation Specifications
Clean the cylinder block bearing housing bore and camshaft journal, removing oil and burrs. Check the compatibility of the journal tolerance (h6) and bearing housing bore tolerance (H7).

Use cold pressing, pressing evenly with a special sleeve. Do not hammer. Ensure the bearing is not deformed. The positioning lip should be embedded in the cylinder block positioning groove.

After installation, check the radial clearance (0.03-0.06 mm) to ensure smooth operation and no jamming.

Maintenance Recommendations
Check the oil pressure and camshaft noise every 2000 working hours. If abnormal pressure or noise is found, disassemble, inspect, and replace with original factory bearings.

When replacing, you must use the original CAT 2H-7878 part of the same model to avoid premature bearing failure and damage to the valve train due to incompatible size or material.