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Caterpillar 3306TA Engine

The Caterpillar 3306TA (Turbocharged-Aftercooled) is a premium, inline 6-cylinder diesel configuration within the legendary 3300-series engine family. Renowned worldwide as one of Caterpillar's most durable and reliable powerplants, it is heavily relied upon in large earthmoving equipment (such as the D6H and D7G dozers, 235 excavators, and 966 loaders), heavy-duty haul trucks, industrial generator sets, and marine propulsion systems. The engine employs replaceable wet-type cylinder liners and a cylinder head spacer plate design, maximizing block integrity and permitting multiple field overhauls. The integration of a turbocharger and aftercooler lowers intake temperatures to optimize combustion efficiency. Field technicians regard the 3306TA as an industry standard for mechanical simplicity and severe-duty survival, provided correct anti-cavitation coolant chemistry is maintained.

Fuel Injection Type: Uses direct injection (DI) via pencil-type fuel injectors or capsule nozzles fed by external steel high-pressure fuel lines. Fuel Injection Pump: Mechanical, sleeve-metered injection pump or high-pressure scroll fuel system, depending on the serial number prefix. Fuel Transfer: A mechanical fuel transfer pump maintains a low-pressure supply of 30 to 40 psi to the injection pump gallery. Governor: Mechanical flyweight governor integrated directly onto the rear of the fuel injection pump housing.

Lubrication System: Full-pressure, wet-sump system driven by a gear-type oil pump. Oil Filtration: Features a spin-on, full-flow bypass oil filter paired with an integrated plate-type oil cooler element. Service: Mechanics must monitor oil pressure closely during cold starts. Shavings in the oil filter or a severe drop in hot idle pressure indicate primary main or connecting rod bearing degradation. Cooling System: Liquid-cooled, closed-loop circuit utilizing a centrifugal, gear-driven water pump. Flow Circuit: Coolant is forced through the engine block jacket, ascending into the cylinder head, and regulated by a single kapsel-type thermostat (regulator) housed at the front upper water outlet.

General Technical Data

Engine Specifications

Engine Model ............... Caterpillar 3306TA
Engine Type ............... 4-cycle inline 6-cylinder direct injection liquid-cooled diesel
Number of Cylinders ............... 6
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 4.76 (121.0)
Engine Stroke, in (mm) ............... 6.00 (152.0)
Displacement, cu.in (L) ............... 638 (10.5)
Rated Engine Power, hp (kW) ............... 218-350 (162-260)
Rated Engine Speed, rpm ............... 2000-2200
Peak Torque ............... 750-1200 Nm (553-885 lb-ft) at 1200-1500 rpm
Idle Speed ............... 650-750 rpm
Aspiration Type ............... Turbocharged and Aftercooled
Operating Speed ............... 2000 rpm
Compression Ratio ............... 14.0:1-15.5:1
Firing Order ............... 1-5-3-6-2-4
Crankshaft Type ............... Forged steel
Piston Type ............... Cast-aluminum alloy
Con Rod Type ............... Forged steel
Cylinder Block Type ............... Cast iron
Cylinder Head Type ............... Cast iron
Lubrication System ............... Full-pressure
Oil Pump Type ............... Gear-driven
Oil Filter Type ............... Full-flow, spin-on
Cooling System ............... Liquid-cooled
Water Pump Type ............... Belt-driven, centrifugal
Air Cleaner Type ............... Dry dual-stage
Starting System ............... Electric Starter
Electrical System ............... 12V or 24V
Alternator Rating, Amps ............... 45-100

Fuel System

Fuel System ............... Direct injection
Injection Pump Type ............... Rotary
Fuel System Control ............... Mechanical
Governor Type ............... Mechanical
Fuel Injector Type ............... Multi-hole
Fuel Type ............... Diesel Fuel

Dimensions and Weight

Overall Length, in (mm) ............... 51.2-59.1 (1300-1500)
Overall Width, in (mm) ............... 33.5-37.4 (850-950)
Overall Height, in (mm) ............... 41.3-49.2 (1100-1250)
Dry Weight, lbs (kg) ............... 2640-3300 (1200-1500)

Maintenance Data

Service Information

Thermostat begins opening ............... 82C (180F)
Thermostat fully open ............... 95C (203F)
Cooling system pressure ............... 70-100 kPa (10-15 psi)
Operating oil pressure ............... 345-550 kPa (50-80 psi)
Idle oil pressure ............... 140-275 kPa (20-40 psi)
Intake Valve Clearance, in (mm) ............... 0.015-0.017 (0.38-0.43)
Exhaust Valve Clearance, in (mm) ............... 0.025-0.027 (0.64-0.69)

Engine Oil and Coolant

Engine Oil Type .................. SAE 10W-30, 15W-40
API Service Classifications ......................... CF/CH-4 or higher
Engine Oil Capacity, qts (L) .................. 28.4-35.7 (27.0-34.0)
Coolant Capacity, qts (L) ............... 31.5-52.2 (30.0-50.0)

Service Intervals

Change oil and filter ............... Every 250 hours
Replace fuel filters ............... Every 300 hours
Inspect air filter ............... Every 50 hours
Change coolant ............... Every 2 years
Valve-lash adjustment ............... Every 1000 hours
Injector inspection ............... Every 1000-1500 hours
Compression test ............... Every 2000 hours
Drain water separator ............... As required
Belt inspection ............... As required

Service Specifications

Cylinder Bore Inside Diameter, in (mm) ................ 4.750-4.752 (120.65-120.70)
Crankshaft Journal Outside Diameter, in (mm) ................ 3.4990-3.5000 (88.875-88.900)
Crank Pin Outside Diameter, in (mm) ................ 2.9987-3.0003 (76.167-76.208)
Crankshaft End Play, in (mm) ................ 0.007-0.025 (0.17-0.63)
Intake Valve Stem Outside Diameter, in (mm) ................ 0.3717-0.3725 (9.441-9.462)
Exhaust Valve Stem Outside Diameter, in (mm) ................ 0.3705-0.3713 (9.411-9.431)
Intake Valve Guide Inside Diameter (Installed), in (mm) ................ 0.3734-0.3744 (9.484-9.510)
Exhaust Valve Guide Inside Diameter (Installed), in (mm) ................ 0.3734-0.3744 (9.484-9.510)
Intake Valve Stem to Guide Clearance, in (mm) ................ 0.0009-0.0027 (0.022-0.069)
Exhaust Valve Stem to Guide Clearance, in (mm) ................ 0.0021-0.0039 (0.053-0.099)
Intake Valve Spring Free Length, in (mm) ................ 2.47 (62.7)
Exhaust Valve Spring Free Length, in (mm) ................ 2.47 (62.7)
Intake Cam Height, in (mm) ................ 1.844-1.856 (46.84-47.14)
Exhaust Cam Height, in (mm) ................ 1.844-1.856 (46.84-47.14)
Piston Pin Outside Diameter, in (mm) ................ 1.5011-1.5013 (38.128-38.133)
Piston Pin to Piston Bore Clearance, in (mm) ................ 0.0002-0.0008 (0.005-0.020)
Top Ring Side Clearance, in (mm) ................ 0.0031-0.0051 (0.079-0.130)
Second Ring Side Clearance, in (mm) ................ 0.0024-0.0043 (0.061-0.109)
Oil Ring Side Clearance, in (mm) ................ 0.0016-0.0035 (0.041-0.089)
Top Ring End Gap, in (mm) ................ 0.0170-0.0320 (0.432-0.813)
Second Ring End Gap, in (mm) ................ 0.0150-0.0270 (0.381-0.686)
Oil Ring End Gap, in (mm) ................ 0.0100-0.0220 (0.254-0.559)

Tightening Torque Specs

Cylinder head bolts ............... 270-310 Nm (200-230 lb-ft)
Main-bearing caps ............... 400-450 Nm (295-330 lb-ft)
Connecting-rod bolts ............... 155-175 Nm (114-130 lb-ft)
Flywheel bolts ............... 380-420 Nm (280-310 lb-ft)
Crankshaft pulley bolt ............... 450-500 Nm (332-370 lb-ft)
Oil drain plug ............... 50-70 Nm (37-52 lb-ft)
Injector hold-downs ............... 35-45 Nm (26-33 lb-ft)

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• Caterpillar Engines Specs
  
• Cat 3306B Specs
  
• Cat 3306C Specs
  
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• Cat 3406A Specs
  
• Cat 3406B Specs
  

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