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Caterpillar 3176B Engine

The Caterpillar 3176B is an inline six-cylinder, four-stroke diesel engine with a displacement of 10.3 liters (628 cubic inches). It represents a critical evolutionary design phase for Caterpillar, introducing Electronic Control Modules (ECM) and advanced fuel delivery systems to the heavy-duty truck, industrial, and marine markets. The 3176B design utilizes a unique lightweight structure featuring a cast-iron crankcase paired with a specialized top deck spacer plate, mid-stop cylinder liners, and an overhead camshaft operating without traditional non-replaceable cam bearings. While celebrated for its high power-to-weight ratio and precise electronic throttle handling, service technicians emphasize that this platform demands rigorous maintenance schedules, careful inspection of structural seam seals to prevent oil/coolant transfer, and precision liner projection monitoring during overhauls.

Fuel System Type: Electronically Controlled Unit Injection (EUI) utilizing a high-pressure mechanical injector mechanism for each cylinder, actuated directly by the overhead camshaft. Delivery Mechanics: A mechanical fuel transfer pump draws fuel from the supply tank, routing it through the electronic control module (ECM) cooling plate, the primary/secondary filter bases, and into integrated fuel manifolds. Operational Pressures: System pressure is governed by an orificed fuel pressure regulator valve located on the return manifold, maintaining a nominal operating pressure of 60 to 91 psi (413 to 630 kPa) under load conditions. Low fuel pressure below 75 psi requires immediate filter element tracking and lift pump diagnostic tests.

Lubrication System Configuration: Full pressure, wet-sump lubrication system featuring a gear-driven oil pump and an integrated high-capacity oil cooler core. Service Protocol: Demands routine oil analysis to monitor for potential fuel or coolant migration across the block spacer boundaries and cylinder liner seats.

Cooling System Configuration: Forced-circulation liquid cooling system managed by a centrifugal jacket water pump, standard thermostats, and an Air-to-Air AfterCooled (ATAAC) intake path. Maintenance Points: The water pump features an external weep hole to safeguard the crankcase; keeping this hole unobstructed prevents failed water seals from forcing high-pressure coolant past internal barriers into the oil pan.

General Technical Data

Engine Specifications

Engine Model ............... Caterpillar 3176B
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) ............... 350-365 (261-272)
Rated Engine Power (Marine), hp (kW) ............... 450-600 (335-448)
Rated Engine Speed (Highway Trucks), 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 (ATAAC)
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 ............... 130-160

Fuel System

Fuel System ............... Electronic Unit Injection (EUI)
Fuel Pump Type ............... Gear-type, transfer
Governor Type ............... Electronic
Injection Pressure, bar ............... 1585
Fuel Type ............... Diesel Fuel

Dimensions and Weight

Overall Length, in (mm) ............... 60.8 (1545)
Overall Width, in (mm) ............... 37.4 (950)
Overall Height, in (mm) ............... 40.0 (1025)
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) .................. 31.5 (30.0)
Coolant Capacity, qts (L) ............... 47.3 (45.0)

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 3176 Specs
  
• Cat 3176C Specs
  

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