CAT 067-7842 PLUNGER

CAT 067-7842 is a Caterpillar original equipment manufacturer (OEM) fuel injection system plunger (pure OEM information, no additional description). It is compatible with the high-pressure common rail fuel pump of C13/C15/C18 engines, used for high-pressure fuel delivery, precisely controlling injection pressure and fuel quantity to ensure stable engine power output and fuel economy.

Core Parameters and Information

Item Details
Part Model: CAT 067-7842 (0677842) Fuel Pump Plunger

Structure Type: Integral solid plunger, including precision guide section, sealing ring groove, pressure balance groove, spiral oil control groove, plunger head (spherical seal)

Material: Plunger body: High carbon chromium bearing steel (GCr15, HRC62-65, mirror polished Ra≤0.02 μm); Surface: DLC diamond-like carbon coating (thickness 3-5 μm, hardness HV1800-2200); Weight: 0.18 kg

Key Dimensions: Plunger diameter 12 mm, total length 85 mm, guide section length 25 mm, sealing ring groove 3×φ11.8 mm (width 1.5 mm, depth 0.2 mm), spiral groove lead 18 mm, head spherical radius R6 mm, mounting shoulder diameter 15 mm

Performance Parameters: Rated working pressure 220 MPa, maximum pressure 250 MPa, clearance 0.0015-0.0025 mm, reciprocating speed ≤1.2 m/s, operating temperature -40℃ to 150℃, fatigue life ≥10⁷ cycles

Compatibility Standards: Complies with ISO 4008 high-pressure fuel system standard, plunger straightness ≤0.001 mm, roundness ≤0.0005 mm, runout ≤0.002 mm

Compatible Models and Assemblies

Compatible Parts: 319-0675 fuel pump assembly, 067-7785 camshaft bearing assembly, 10R-2465 camshaft, 236-7890 valve rocker arm

Compatible Equipment: CAT 336D2/349D2 excavator, 980K/982M loader, D8T/D9T bulldozer (C13/C15/C18) (Engine), used for high-pressure common rail fuel pump fuel pressurization.

Matching: 067-7842 Plunger + 067-7843 Plunger Sleeve + 067-7844 Plunger Spring + 067-7845 Spring Seat, 6 pieces per engine (inline 6 cylinders)

Installation and Maintenance Points:

Clean the plunger sleeve mounting hole and plunger surface, checking for scratches, burrs, and DLC coating peeling. Ensure the fit clearance meets standards and prevent impurities from entering.

Use a dedicated guide tool (075-2347) to slowly insert the plunger into the sleeve, ensuring the helical groove aligns with the control groove. Install the spring seat and plunger spring, with a preload of 120-150 N.

After installation, test for no plunger jamming during reciprocating motion, no leakage at a sealing pressure of 220 MPa, fuel injection pressure fluctuation ≤ ±1 MPa, and fuel quantity control accuracy ±0.5%.

Maintenance: Check plunger wear every 2000 hours (replace when radial wear is ≥0.005 mm), replace the high-pressure fuel filter regularly, and use engine oil that meets CAT ECF-3 standards to avoid fuel contamination that could cause coating wear.