CAT 394-0187 BEARING-SLV-GD

CAT 394-0187 YM is a reinforced alloy steel connecting rod assembly for Caterpillar engines. It integrates the connecting rod body, big end cap, bearing, small end bushing, and connecting rod bolts. It is suitable for C9.3 and C13 engines of medium and heavy-duty excavators/loaders and is used to convert the reciprocating motion of the piston into crankshaft rotation power. It can withstand alternating loads and high temperature and high pressure conditions, ensuring efficient power transmission and stable operation of Cat® Parts. The following is structured technical and application information:

Core Technical Parameters

Item Details
Basic Attributes
Model 394-0187 YM, Type: Engine connecting rod assembly (including big end bearing / small end bushing / connecting rod bolt), Material: Micro-alloyed 42CrMo steel, Integral forging + quenching and tempering (HRC28-32), Single weight: Approximately 7.8 kg, Applicable temperature: -30℃ to +300℃, Recommended lubrication: Cat DEO-ULS 15W-40, Bolt material: Grade 12.9 alloy structural steel, Preload torque: 180-200 N・mCat® Parts
Key Dimensions
Small end inner diameter: 50 mm (piston pin tolerance h6), Big end inner diameter: 105 mm (crankshaft pin tolerance h6), Connecting rod center distance: 320 mm (tolerance ±0.15 mm), Rod body cross section: 28 mm × 42 mm (I-beam shape, lightweight design), Big end cap bolt hole diameter: 16 mm mm (4 pieces, evenly distributed), small end bushing thickness 3 mm (bronze alloy + graphite inlay), bearing thickness 2.5 mm (steel back + aluminum-tin alloy coating), connecting rod weight tolerance ≤ ±5 g (for overall machine balance requirements)
Compatible Models and Applications: Compatible with Cat 336D2 and 349D2 excavators, 980M loaders, for piston-crankshaft connections in C9.3 and C13 engines. Supporting parts include connecting rod bearings 394-0188, connecting rod bolts 106-0898, and small end bushings 394-0189. Suitable for speeds of 1500-2200 r/min. Rated load ≥ 80 kN (tensile/compression alternating). Fatigue life ≥ 12000 hours. Cat® Parts
Performance Parameters: Tensile strength ≥ 1200 MPa, Yield strength ≥ 900 MPa, Fatigue strength ≥ 500 MPa (10^7) (Number of cycles), large-end bearing friction coefficient ≤0.0025, small-end bushing wear rate ≤0.01 mm/1000 hours, connecting rod straightness tolerance ≤0.05 mm/overall length, large-end bore roundness tolerance ≤0.005 mm, axial clearance after assembly 0.10-0.20 mm.

Structural and Performance Advantages

High-Strength Design: Made of integral forged 42CrMo steel, heat-treated for both high strength and toughness, suitable for alternating engine load conditions, avoiding the risk of connecting rod breakage.

Precise Transmission: The I-beam shaped rod body is lightweight yet rigid. Precision fit between the large-end bore and crankshaft pin, and between the small-end bushing and piston pin, ensures efficient power transmission and reduces vibration and noise.

Reliable Lubrication: The large-end bearing uses an aluminum-tin alloy coating, and the small-end bushing is made of bronze alloy with graphite inlay, providing inherent lubrication properties. Combined with the engine’s forced lubrication system, this reduces frictional losses.

Easy Assembly: The beveled design of the connecting rod big end facilitates installation and disassembly. Precise bolt preload torque ensures the roundness of the big end bore, extending the service life of the bearing bush.

Installation and Maintenance Points: Before installation, clean the connecting rod, crankshaft pin, and piston pin. Check the straightness of the connecting rod and the roundness of the big end bore. Assemble the big end bearing bush according to the marked direction. Tighten the bolts symmetrically to 180-200 N·m, using a 90° angle method for secondary tightening. After press-fitting the small end bushing, ream the hole to the inner diameter tolerance H7.

After installation, check the connecting rod axial clearance to 0.10-0.20 mm, the big end radial clearance to 0.03-0.05 mm, and ensure the connecting rod swings smoothly without jamming. Perform a 2-hour trial run; the bearing temperature should be ≤90℃, with no abnormal noise or leakage.

Maintenance: Check the connecting rod bolt torque and bearing wear every 2000 hours, and replace the connecting rod bearing and small end bushing every 6000 hours. Avoid overload operation and cold start impact to prevent connecting rod deformation or breakage.