320B Excavator Complete Engine Assembly 129-0741 (3066 S6K-T Diesel Motor)

Tatan Machinery supplies Caterpillar 3066T Mechanical Diesel Engine Assemblies (OEM Reference: 129-0741) specifically built for CAT 320B / 320B L crawler excavators.

  • Application: Caterpillar 320B / 320B L Hydraulic Excavator
  • OEM Cross Reference: 129-0741
  • Build Condition: Professional Remanufactured to OEM Specs (100% Brand-New Pistons, Rings, Liners, Bearings & Gaskets)
  • Fuel System: Heavy-Duty Mechanical In-line Fuel Injection Pump (Direct Injection, Bench Calibrated)
  • Compatibility Guarantee: 1-on-1 verified against your CAT 320B chassis PIN (e.g., 8ES, 1XS, 4XW, 5GW, 6LS prefixes)

Need Serial Number Verification & Direct Pricing for CAT 320B Engine?

Contact Senior Specialist Gavin for free machine nameplate double-check & freight quote:

Description

Caterpillar 320B 3066T Diesel Engine Assembly 125-2988 Tatan Machinery

Tatan Machinery supplies professionally remanufactured Caterpillar 3066T diesel engine assemblies (OEM reference: 129-0741, interchangeable with 129-0741 ) for CAT 320B and 320B L crawler excavators. Rebuilt strictly to OEM tolerance standards with 100% brand-new internal wear components, this drop-in assembly eliminates field overhaul downtime. This page details first-party rebuild specifications, workshop testing standards, field failure diagnostics, and buyer sourcing guidelines.


Supplier Information & Build Status

Supplier:Tatan Machinery (Professional Excavator Parts Supplier)
Product Category:Diesel Engine Assembly /
Excavator Engine Parts
Engine Model:Cat® 3066T Turbocharged Direct-Injection Diesel
OEM Reference: 129-0741
Product Build Condition:Professional Remanufactured to OEM Specs (Genuine Heavy Cast Core + 100% Brand-New Wear Components)
Other Parts Condition:All other excavator components on our site (Hydraulic Pumps, Main Valves, Swing & Travel Motors) are 100% Brand New.
Target Machine:CAT 320B / CAT 320B L Hydraulic Excavators

🏢 Tatan Machinery Engine Staging & Workshop Facility

Physical inventory storage, engine remanufacturing staging, and pre-export testing facility:

Tatan Machinery Excavator Engine Storage and Inspection WarehouseTatan Machinery Excavator Engine Storage and Inspection WarehouseTatan Machinery Excavator Engine Storage and Inspection Warehouse


Physical inventory — ready for global crating. Video calls and warehouse visits welcome.

Technical Specifications

ParameterSpecification Data
Displacement6.37 Liters (389 cu in)
Cylinder ArrangementInline 6-Cylinder, 4-Stroke Mechanical Diesel
Bore × Stroke102 mm × 130 mm (4.02 in × 5.12 in)
Fuel Injection SystemMechanical In-line Injection Pump (Direct Injection)
AspirationTurbocharged (Exhaust Gas Driven)
Cooling CircuitPressurized Water-Cooled with Integrated Oil Cooler
Standard Machine MatchCaterpillar 320B / 320B L Hydraulic Excavators

Remanufacturing Standard: What Makes This Drop-In Ready?

This engine is NOT a cheap used/second-hand salvage yard pull. It is thoroughly disassembled, sonically cleaned, re-machined, and assembled with 100% brand-new critical wear components:

  • Structural Core Inspection: Engine cylinder block and cylinder head are chemically de-carboned, ultrasonic cleaned, and magnaflux-tested for micro-cracks. Deck surfaces precision ground.
  • 100% Brand-New Wear Components Installed: Brand-new pistons, piston ring sets, cylinder liner sleeves, wrist pins, connecting rod bearings, main crankshaft bearings, thrust washers, and complete valve guide seals.
  • Forged Crankshaft Re-Machining: Crankshaft journals micropolished and dynamically balanced to factory runout specifications.
  • 100% Brand-New Gasket & Seal Kit: Complete front/rear crankshaft oil seals, head gasket, and manifold seals renewed to eliminate field oil/coolant weeping.
  • Mechanical Injection Pump & Turbo Overhaul: In-line pump fitted with new plungers and calibrated on a fuel test bench for balanced 6-cylinder fuel delivery.

When to Replace the Cat 3066T Engine: Field Diagnostic Criteria

The Caterpillar 320B is one of the most durable excavators ever built, but after 15,000+ service hours, worn cylinder tolerances make on-site overhauls cost-prohibitive. We recommend installing a complete remanufactured assembly under these symptoms:

  • Mechanical Injection Pump Wear & Hot-Start Failure: Plungers lose injection pressure once hydraulic oil reaches 80°C, causing hard hot-cranking, severe digging bog-down, or sudden engine stall under boom relief pressure.
  • Severe Cylinder Bore Scoring & Heavy Blow-by: Piston ring land collapse allowing pressurized combustion gases into the oil pan, causing heavy blow-by smoke from the breather pipe and continuous oil burning.
  • Crankshaft Bearing Seizure / Spun Rod Journals: Oil dilution or low pressure scoring main crankshaft journals beyond standard undersize limits, rendering the bare block unrepairable on-site.
  • Cylinder Head Thermal Cracking: Cracks developing between injector sleeves and exhaust valve seats from cooling system failure, pushing exhaust pressure directly into the coolant reservoir.

Workshop Testing Standards (Pre-Delivery Inspection)

Every remanufactured Cat 3066T undergoes mandatory pre-shipment quality verification:

  1. Manual Crankshaft 720° Barring Test: Smooth rotation verification without valvetrain binding or mechanical interference.
  2. Mechanical Fuel Pump Timing & Plunger Check: Verification of fuel spill timing and injection nozzle atomization pattern.
  3. Lube Oil Gallery Pressure Priming: Pre-filling the oil circuit to confirm pressurized flow through main journals and turbocharger feed lines.
  4. Block & Head Pneumatic Leak Hold Test: Air hold test to guarantee oil cooler bundle and cylinder head gasket sealing integrity.
  5. Flywheel Coupler Concentricity Dial Check: Ensuring 100% true alignment for the hydraulic main pump drive coupling.

📹 Live 3066T Engine Workshop Inspection Video

Watch our workshop technician verify rotation, stamped serial numbers, and mounting ports:


✓ Real physical unit filmed at Tatan Machinery workshop

Export Heavy-Duty Packaging Process

To protect the mechanical fuel injection pump, turbocharger, and cast flywheel housing during ocean transit:

  • Internal & External Anti-Rust Preservation: All raw machined surfaces, crankshaft snout, and flywheel teeth coated with high-grade anti-corrosion grease.
  • Dust Caps on All Openings: Intake manifold, exhaust elbow, water inlets, and fuel feed fittings sealed with heavy-duty protective plugs.
  • Direct Sump-Skid Bolting: The engine is anchored securely to heavy timber base skids through rigid mounting brackets.
  • ISPM 15 Fumigation-Free Solid Crate: High-density export plywood crate secured with galvanized steel strapping.

Heavy-duty Export Wooden Crate Packaging for CAT 320B EngineHeavy-duty Export Wooden Crate Packaging for CAT 320B Engine

Actual export wooden crate packaging and internal skid bracing for Cat 3066T

Global Shipping & Customs Documentation

Fast, reliable dispatch tailored for commercial contractors and parts wholesalers worldwide:

  • Emergency Machine Down (AOG Freight): Priority air cargo via DHL Aviation, FedEx Heavy Cargo, or direct airline belly freight within 3–7 business days.
  • Ocean Container Freight (LCL / FCL): Consolidated container shipping to all major commercial seaports worldwide.
  • Complete Export Documents: Commercial Invoices with correct HS Code (8408.20), Packing Lists, and Certificates of Origin for smooth customs clearance.

Tatan Machinery Global Logistics and Shipping Dispatch for CAT 320B Parts

Container loading and air freight dispatch supported by global logistics partners

Critical Installation Guidelines (320B Technician Checklist)

To prevent instant failure of the newly installed engine assembly, field technicians MUST adhere to the following steps:

  1. MANDATORY: Radiator & Oil Cooler Flushing: If the old engine experienced bearing seizure or cracked pistons, metal shavings reside in the external oil cooler core and hoses. You MUST thoroughly flush or replace the oil cooler before connecting oil lines to the new engine!
  2. Pre-Lube the Engine: Pre-fill the new oil filter with 15W-40 oil. Disconnect the manual fuel shut-off solenoid wire and crank the starter motor in 10-second bursts until the oil pressure light turns off or the gauge rises. NEVER fire up a dry engine!
  3. Mechanical Fuel Pump Air Bleeding: Pump the hand primer on the fuel filter base until clear diesel emerges without bubbles from the injection pump bleeder screw. Air locks will starve the mechanical plungers of initial lubrication.
  4. Check Flywheel Coupling Damper: Inspect the rubber drive coupling connecting to the hydraulic pump (SBS80 / AP-12). Hardened or cracked rubber elements cause excessive crankshaft torsional vibration and rear main seal leakage.
  5. Throttle Linkage Calibration: Verify that the governor lever on the injection pump reaches full idle and full load stops when adjusting the 320B excavator throttle motor cable.

Buyer Frequently Asked Questions (Purchasing FAQ)

Q: Is this 3066T engine brand new or remanufactured? What is the actual build quality?

A: This engine assembly is professionally remanufactured strictly to Caterpillar OEM tolerances. We do not sell worn salvage yard engines. The cast iron block, cylinder head, and forged crankshaft undergo ultrasonic cleaning, crack detection, and precision machining. 100% of internal wear parts are replaced with brand-new components (new pistons, rings, liners, bearings, valves, and a complete gasket seal kit). It provides the exact performance and lifespan of an OEM build at a fraction of dealer pricing.

Q: Are all other products on your website remanufactured as well?

A: No. Only our heavy diesel engine assemblies are professionally remanufactured. All other excavator spare parts supplied by Tatan Machinery—including our hydraulic main pumps, main control valves, final drive travel motors, swing motors, and undercarriage components—are 100% Brand New (OEM-Grade Aftermarket) ready for immediate jobsite duty.

Q: CAT 320B excavators have various serial prefixes (8ES, 1XS, 4XW, 5GW, etc.). How do you ensure it will fit my chassis?

A: Different 320B manufacturing origins (e.g., Japan vs. US builds) can feature different throttle stepper motor brackets, oil pan depths, or flywheel housing bolt patterns. We eliminate guesswork: send your 320B serial number (PIN) from the cab tag and clear photos of your old engine’s pump side and flywheel face to Gavin. We cross-verify the engineering arrangement in the official Caterpillar SIS database within 10 minutes.

Q: Can I see live photos and stamped block numbers of the actual engine before paying?

A: Absolutely yes. Prior to balance payment and dispatch, we send clear photos and live video of the specific unit assigned to your order. You will see the stamped serial numbers, mechanical injection pump tags, flywheel teeth, and the complete wooden box packaging process.

Q: What happens if the crate is damaged during sea freight, and what customs paperwork do you provide?

A: Every shipment from Tatan Machinery is protected by full commercial marine cargo insurance. The engine is bolted down directly onto internal skids within a fumigation-free solid plywood crate. We supply commercial invoices with accurate HS Codes (8408.20), detailed packing lists, and Certificates of Origin for smooth customs clearance at your destination port.


🔗 Frequently Purchased Together with CAT 320B Diesel Engine:

Get Wholesale Factory Quote for 3066T 129-0741 Engine Assembly

Looking for direct factory pricing, stock availability, or technical verification for Cat 3066T engines? Contact senior specialist Gavin now!

💡 Fast Quote: Send your engine serial number or nameplate photos for an accurate match within 10 minutes!

* Note: Wholesale Reference Price Starts From $300.00. Please contact Gavin for a final customized quote based on freight destination and configuration.

* Note: Wholesale Reference Price Starts From $300.00. Please contact Gavin for a final customized quote.

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