CAT 8C-7873 3\ Outer Diameter Screw Conveyor Drive Shaft Extension

CAT 8C-7873 is a Caterpillar original equipment manufacturer (OEM) fuel system injector extension rod (for connecting high-pressure fuel lines and injectors, used in deep cylinder head mounting spaces). The following is precise information (no additional description):

Core Parameters and Information

Item Details
Part Model: CAT 8C-7873 (8C7873) Injector Extension Rod

Part Type: High-pressure fuel system extension rod, for connecting injectors and high-pressure fuel lines, used to extend the fuel path in deep cylinder head injector mounting positions

Material: 42CrMo alloy structural steel, surface nitrided, hardness HV650-750, tensile strength ≥1080MPa, resistant to high-pressure fuel corrosion

Key Dimensions: Overall length 125.00mm, rod diameter 14.00mm, threaded end M14×1.5 (for injector interface), connecting end inner diameter 10.00mm (for high-pressure fuel line outer diameter 10mm), positioning step diameter 16.00mm, Step height 5.00mm, Mounting thread length 18.00mm

Structural Features: One end has an external thread (M14×1.5) for connecting to the injector; the other end has an internal hole for fitting the high-pressure fuel line; it features a positioning step in the middle; the anti-loosening washer groove width is 2.00mm; after installation, the positioning step fits flush with the cylinder head plane.

Compatible Structure: Compatible with injector interface M14×1.5 (tolerance 6g), high-pressure fuel line outer diameter 10.00mm (tolerance h8), mounting hole depth 120.00mm, positioning step mating surface flatness ≤0.02mm

Applicable Operating Conditions: Engine direct injection system, working pressure 0-180MPa, working temperature -40℃ to +150℃, compatible with diesel/biodiesel blended fuels

Compatible Engines and Assemblies:

Engine: CAT 3126B, 3126E, C7, C9 (Compatible with cylinder head injector mounting assembly)

Compatible assemblies: 3126B engine injector mounting kit, C7 cylinder head high-pressure fuel line extension assembly

Installation and Fitting Points:

Before installation, clean the threads and inner bore to remove oil and impurities. Apply high-pressure thread sealant (CAT 1U-6396) to the threads.

Align the threaded end of the extension rod with the injector interface and tighten it with a torque wrench to 25-30 N·m, ensuring the positioning step is flush with the cylinder head surface without gaps.

After inserting the high-pressure fuel line into the inner bore, secure it with clamps. The clamp torque should be 8-10 N·m, ensuring no fuel line leaks.

After installation, perform a high-pressure test (180 MPa, hold for 5 minutes). No leaks indicate it is合格 (qualified). For disassembly, use a special socket tool to unscrew it.