320-0680
320-0680 Caterpillar C6.6 Perkins Injector: 2645A747 Specs
320-0680, 2645A747, 10R-7672, 321-3600, 295-9130, 10R-7670, 2645A749, 2645A734, 2645A717CAT C6.6 CRS Electro-Hydraulic Spool ValveG3S33 / Multi-Hole Common Rail Nozzle1800 barProduct Overview
The CATERPILLAR 320-0680 is an authentic heavy-duty common rail diesel fuel injector engineered for 6.6L Caterpillar C6.6 ACERT and Perkins 1106D-E66TA electronically controlled industrial diesel engines compliant with EPA Tier 3 and EU Stage IIIA emissions mandates. Serving as the primary combustion power unit on Caterpillar 320D, 320D L, 321D LCR, and 323D series hydraulic crawler excavators, 924H/930H wheel loaders, and D6K track-type tractors, this injector operates at system rail pressures up to 1800 bar (26,100 psi). The precision multi-hole nozzle geometry coupled with an ultra-responsive electro-hydraulic spool valve executes pilot, main, and post-injection strategies with microsecond timing. Part number 320-0680 interchanges directly with Perkins manufacturing part number 2645A747, production references 321-3600 and 295-9130, and Caterpillar factory remanufactured assemblies 10R-7672, 10R-7670, and 10R-7671. Each injector features an individually calibrated Trim Code representing its exact physical flow curve; entering this calibration into the engine ECM via Cat Electronic Technician ensures seamless multi-cylinder balance, optimal fuel economy, and absolute protection against diagnostic trouble codes 100-3 (oil pressure sensor) and 164-2/164-3 (fuel pressure variance).
Always record the unique Caterpillar Trim Code (Injector Calibration File) engraved on the injector body before lowering it into the cylinder head. The 320-0680 (Perkins 2645A747, Reman 10R-7672) is the primary electro-hydraulic common rail injector for Caterpillar C6.6 ACERT and Perkins 1106D Tier 3 / Stage IIIA industrial engines powering CAT 320D and 323D hydraulic excavators. Torque the injector hold-down clamp bolt to exactly 30 N·m (22 lb·ft) and the high-pressure fuel supply line nut to 30 N·m (22 lb·ft). Programming the Trim File into the engine ECM via Cat ET (Electronic Technician) is mandatory to eliminate cylinder contribution imbalances and rail pressure deviation fault codes.
Vehicle & Engine Fitment
| Vehicle | Engine | Years |
|---|---|---|
| Caterpillar 320D / 320D L / 320D LN | Caterpillar C4.4 / C6.4 / C6.6 ACERT & Perkins 1104D / 1106D | 2006-2015 |
| Caterpillar 323D / 323D L / 323D LN | Caterpillar C4.4 / C6.4 / C6.6 ACERT & Perkins 1104D / 1106D | 2006-2015 |
| Caterpillar 321D LCR Short Radius Excavator | Caterpillar C4.4 / C6.4 / C6.6 ACERT & Perkins 1104D / 1106D | 2006-2014 |
| Caterpillar 924H / 928H / 930H Wheel Loader | Caterpillar C4.4 / C6.4 / C6.6 ACERT & Perkins 1104D / 1106D | 2007-2015 |
| Caterpillar D6K / D6N Track-Type Tractor / Dozer | Caterpillar C4.4 / C6.4 / C6.6 ACERT & Perkins 1104D / 1106D | 2007-2016 |
| Perkins 1106D-E66TA Industrial & Genset Engine | Caterpillar C4.4 / C6.4 / C6.6 ACERT & Perkins 1104D / 1106D | 2006-2020 |
Technical Specifications
| Specification | Value |
|---|---|
| SKU | 320-0680 |
| Brand | CATERPILLAR |
| Type | Electro-Hydraulic Common Rail Fuel Injector |
| OE Number | 320-0680, 2645A747, 10R-7672, 321-3600, 295-9130, 10R-7670 |
| Injection System | Caterpillar Common Rail System (CRS) |
| Operating PressureCore Spec | |
| Torque Spec | 30 N·m |
| Hold Down Torque | 30 N·m |
| Warranty | 12 Months |
| Emission Standard | EPA Tier 3 / EU Stage IIIA |
| Engine Family | Caterpillar C6.6 ACERT & Perkins 1106D (6.6L) |
| Coding Required | Yes (Cat ET Injector Trim File / Trim Code) |
Installation Tips
Tools needed: Caterpillar Electronic Technician (Cat ET) diagnostic software with Comm Adapter 3, Calibrated torque wrench (10 to 60 N·m range), Brass cylinder head injector sleeve wire brush and vacuum suction extractor, Clean metric flare nut crowfoot wrench set (17 mm and 19 mm)
- Clean the cylinder head injector bore thoroughly using a brass bore brush and vacuum suction; ensure all hardened carbon deposits and any remnants of the old copper seating washer are completely extracted.
- Inspect the injector hold-down clamp, spherical washer, and bolt threads. Lubricate the clamp bolt threads and contact face with clean 15W-40 heavy-duty engine oil.
- Fit a new copper sealing washer onto the injector nozzle shank. Install a new upper body O-ring seal; lubricate the O-ring with clean engine oil, strictly keeping the nozzle spray tip dry and contaminant-free.
- Insert injector 320-0680 squarely into the cylinder head sleeve until the nozzle washer firmly seats against the lower cylinder head surface.
- Position the injector hold-down clamp squarely over the injector shoulder and thread the clamp bolt finger-tight.
- Connect the high-pressure fuel line between the fuel rail and injector inlet fitting, threading both tube nuts by hand to guarantee clean thread engagement without cross-threading.
- Tighten the injector hold-down clamp bolt to a final torque of 30 N·m (22 lb·ft). Verify that the injector body remains square and does not cock or bind during torquing.
- Tighten the high-pressure fuel injection line nuts to 30 N·m (22 lb·ft) at both the injector inlet fitting and the common fuel rail connection.
- Reattach the solenoid terminal wire nuts; tighten to 2.5 N·m (22 lb·in). Do not overtighten, which can fracture the molded internal solenoid studs.
- Connect Cat ET via the diagnostic port, access Service > Calibrations > Injector Code Calibration, and enter the alphanumeric Trim File / Trim Code printed on the injector body into the corresponding cylinder.
- Mandatory Trim Code Calibration: Cat C6.6 ECM relies on the Trim File to apply micro-second fuel delivery compensations across varying load and speed bands. Running uncalibrated injectors triggers rough idle, excessive black exhaust smoke, and cylinder balance DTCs.
- Single-Use Copper Washer Rule: Never reuse a copper sealing washer. Reusing an old washer or stacking multiple washers alters nozzle combustion chamber protrusion depth, leading to incomplete combustion, localized cylinder head overheating, and severe combustion gas blow-by.
- Quill Tube & Line Alignment: Before applying final torque to the clamp bolt, ensure the fuel line flare nut threads smoothly by hand. Forcing an unaligned tube nut creates metal galling and high-pressure fuel leakage beneath the valve cover.
- Zero Starting Fluid Policy: Never introduce ether or aerosol starting fluids into the intake manifold of a common rail C6.6 engine. Extreme cylinder pressure spikes will shatter the nozzle tip and cause catastrophic piston crown erosion.
Frequently Asked Questions
What machines and engines use Caterpillar injector 320-0680?
Part number 320-0680 is engineered for 6.6L Caterpillar C6.6 ACERT and Perkins 1106D-E66TA Tier 3 / Stage IIIA diesel engines powering CAT 320D, 320D L, 321D LCR, and 323D hydraulic crawler excavators, 924H/930H wheel loaders, D6K dozers, and Perkins industrial power generators.
What OEM part numbers interchange with Caterpillar 320-0680?
Caterpillar 320-0680 directly interchanges with Perkins OE number 2645A747, Caterpillar production numbers 321-3600, 295-9130, 292-3780, and Caterpillar factory remanufactured part numbers 10R-7672, 10R-7670, and 10R-7671.
What are the installation torque specifications for injector 320-0680?
The injector hold-down clamp bolt must be tightened to 30 N·m (22 lb·ft). The high-pressure fuel injection line flare nuts at both the fuel rail and injector inlet must be torqued to 30 N·m (22 lb·ft), and the solenoid electrical harness nuts to 2.5 N·m (22 lb·in).
Why is Trim Code calibration required in Cat ET after installation?
Each common rail injector possesses minute hydraulic flow tolerances generated during precision manufacturing. Entering the Trim Code via Cat ET programs the ECM with specific delivery offset parameters for each cylinder, preventing rough running, power loss, and rail pressure control trouble codes.
Diagnostic Trouble Codes & Fault Protocols
Common diagnostic trouble codes (DTCs) triggered when this common rail injector experiences wear, circuit faults, or calibration drift:
Fuel Rail / System Pressure Too Low
Excessive internal backleak from worn control valve seats drops common rail pressure below target under engine load.
Injector Circuit Malfunction / Open Circuit
Solenoid coil resistance drift (0.2-0.5 Ω) or piezo stack degradation triggers driver stage shutdown on affected cylinders.
Cylinder Misfire & Balancing Deviation
Carbon-clogged nozzle spray holes or missing IMA calibration causes uneven cylinder contribution. Recode ECM and verify washer seating.
Fuel Rail / System Pressure Too High
Spill line backpressure or stuck metering valve prevents rail depressurization, creating overpressure risks under load.
Technical Diagnostic & Service Protocols
Authoritative field procedures, diagnostic testing thresholds, and service SOPs for this assembly.