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Caterpillar 3176 Engine

The Caterpillar 3176 is a heavy-duty, inline four-stroke diesel engine engineered primarily for on-highway trucks, construction machinery, and marine vessels. Introduced as a pioneer in Cat’s electronic evolution, it balances structural rigidity with weight reduction by utilizing a cast-iron block and lightweight upper deck designs. Known for its exceptional power-to-weight ratio, it integrates an overhead camshaft configuration and high-pressure electronic fuel controls to optimize thermal efficiency and decrease lifecycle emissions.

The 3176 utilizes an Electronic Unit Injection (EUI) system managed by an Electronic Control Module (ECM). Supply Loop: A mechanical fuel transfer pump draws fuel from the storage tank, pushing it through the ECM cooling plate and the primary fuel filter base into the cylinder head supply manifold. System Pressure: Regulated by an orificed check valve in the return manifold, maintaining a nominal operating pressure of 630 kPa (91 psi) at rated RPM. Injection Mechanism: Individual unit injectors are housed directly in each cylinder under the overhead camshaft. The camshaft acts mechanically as a pump to build high injection pressure, while the ECM actuates a solenoid valve on each injector to precisely control injection timing and duration.

The engine features a full-pressure, wet-sump lubrication loop driven by a gear-type oil pump. Oil flows directly from the pan through an oil cooler and a primary full-flow filter base. Thermal Management: A dedicated bypass valve regulates passage through the oil cooler, maintaining proper viscosity by closing completely when oil temperature reaches 100C to 103C. Component Lubrication: Pressurized oil channels through internal galleries to supply the main bearings, connecting rods, overhead camshaft journals, and under-piston cooling jets.

The cooling configuration relies on a gear-driven centrifugal water pump to force coolant through the cylinder block jacket, cylinder head, and engine oil cooler. Air Induction Cooling: Utilizes a Turbocharged and Air-to-Air AfterCooled (ATAAC) system to lower intake air temperature, ensuring high density for combustion. Regulation: Regulated by dual conventional thermostats that block flow to the radiator until optimal operating temperature is reached, diverting flow back through a bypass tube to the pump inlet.

General Technical Data

Engine Specifications

Engine Model ............... Caterpillar 3176
Engine Type ............... 4-cycle inline 6-cylinder turbocharged ATAAC liquid-cooled diesel
Number of Cylinders ............... 6
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 4.92 (125.0)
Engine Stroke, in (mm) ............... 5.51 (140.0)
Displacement, cu.in (L) ............... 629 (10.3)
Rated Engine Power (Highway Trucks), hp (kW) ............... 250-325 (187-242)
Rated Engine Power (Industrial), hp (kW) ............... 248-268 (185-200)
Rated Engine Power (Marine), hp (kW) ............... 600 (448)
Rated Engine Speed (Industrial), rpm ............... 1700-2100
Rated Engine Speed (Marine), rpm ............... 2000-2300
Peak Torque ............... 1350-1890 lb-ft (1830-2560 Nm) at 1200-1600 rpm
Aspiration Type ............... Turbocharged and Air-to-Air Aftercooled
Operating Speed ............... 1700-2300 rpm
Compression Ratio ............... 16.0:1
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 ............... Gear-driven, centrifugal
Air Cleaner Type ............... Dry, two-stage
Starting System ............... Electric Starter
Electrical System ............... 12V or 24V
Alternator Rating, Amps ............... 105-150

Fuel System

Fuel System ............... Electronic Unit Injection (EUI)
Fuel Pump Type ............... Gear-type, transfer
Governor Type ............... Electronic
Injection Pressure, bar ............... 1380
Fuel Type ............... Diesel Fuel

Dimensions and Weight

Overall Length, in (mm) ............... 60.8 (1545)
Overall Width, in (mm) ............... 38 (965)
Overall Height, in (mm) ............... 39.5 (1000)
Dry Weight, lbs (kg) ............... 2590 (1175)

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 ............... 275-415 kPa (40-60 psi)
Idle oil pressure ............... 55-70 kPa (8-10 psi)
Intake Valve Clearance, in (mm) ............... 0.012-0.018 (0.30-0.46)
Exhaust Valve Clearance, in (mm) ............... 0.022-0.028 (0.56-0.72)

Engine Oil and Coolant

Engine Oil Type .................. SAE 10W-30, 15W-40
API Service Classifications ......................... CH-4, CG-4, or higher
Engine Oil Capacity, qts (L) .................. 35.7 (34.0)
Coolant Capacity, qts (L) ............... 51.5 (49.0)

Service Intervals

Change oil and filter ............... Every 250 hours
Replace fuel filters ............... Every 500 hours
Inspect air filter ............... Every 100 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 ................ 4.9213 in (125.000 mm)
Crankshaft Journal Outside Diameter ................ 3.9370 in (100.000 mm)
Crank Pin Outside Diameter ................ 3.2283 in (82.000 mm)
Crankshaft End Play ................ 0.0040-0.0110 in (0.10-0.28 mm)
Intake Valve Stem Outside Diameter ................ 0.3717 in (9.441 mm)
Exhaust Valve Stem Outside Diameter ................ 0.4907 in (12.464 mm)
Intake Valve Guide Inside Diameter (Installed) ................ 0.3735 in (9.487 mm)
Exhaust Valve Guide Inside Diameter (Installed) ................ 0.4968 in (12.619 mm)
Intake Valve Stem to Guide Clearance ................ 0.0018 in (0.046 mm)
Exhaust Valve Stem to Guide Clearance ................ 0.0061 in (0.155 mm)
Intake Valve Spring Free Length ................ 2.5000 in (63.500 mm)
Exhaust Valve Spring Free Length ................ 2.5000 in (63.500 mm)
Intake Cam Height ................ 3.2800 in (83.312 mm)
Exhaust Cam Height ................ 3.1760 in (80.670 mm)
Piston Pin Outside Diameter ................ 1.9998 in (50.795 mm)
Piston Pin to Piston Bore Clearance ................ 0.0015 in (0.038 mm)
Top Ring Side Clearance ................ 0.0035 in (0.089 mm)
Second Ring Side Clearance ................ 0.0031 in (0.079 mm)
Oil Ring Side Clearance ................ 0.0025 in (0.064 mm)
Top Ring End Gap ................ 0.0157 in (0.400 mm)
Second Ring End Gap ................ 0.0250 in (0.635 mm)
Oil Ring End Gap ................ 0.0150 in (0.381 mm)

Tightening Torque Specs

Cylinder Head Bolts ............... 300 Nm (221 lb-ft)
Main Bearing Cap Bolts (Vertical) ............... 340 Nm (251 lb-ft)
Main Bearing Cap Cross Bolts ............... 190 Nm (140 lb-ft)
Connecting Rod Bolts ............... 190 Nm (140 lb-ft)
Flywheel Housing-to-Block Bolts ............... 190 Nm (140 lb-ft)
Flywheel-to-Crankshaft Bolts ............... 285 Nm (210 lb-ft)
Unit Injector Clamp Bolt ............... 35 Nm (26 lb-ft)
Oil Pan Bolts ............... 55 Nm (41 lb-ft)

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• Caterpillar Engines Specs
  
• Cat 3126 DITA Specs
  
• Cat 3126B Specs
  
• Cat 3126E Specs
  
• Cat 3176B Specs
  
• Cat 3176C Specs
  

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