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Caterpillar 3116 Engine

The Caterpillar 3116 is a heavy-duty, inline 6-cylinder, 4-stroke cycle diesel engine introduced in 1988. Known for its completely mechanical design, this engine features a cast-iron block with dry cylinder liners, a forged steel crankshaft, and overhead valves (OHV). It was widely deployed across medium-duty trucks, marine propulsion vessels, and industrial heavy equipment due to its high power-to-weight ratio and reliable structural engineering.

Fuel System Type: Mechanical Unit Injection (MUI) system. Injection Mechanism: Features individual, high-precision unit injectors for each cylinder driven mechanically by the engine camshaft via pushrods and rocker arms. This design eliminates external high-pressure fuel lines. Fuel Delivery: A mechanical fuel transfer pump pulls fuel from the tank, passes it through a primary fuel filter/water separator, and pushes it through a secondary filter into the internal cylinder head fuel gallery at regulated pressure. Governor and Rack Control: Engine speed and fuel metering are modulated by a mechanical governor linked to a common control rack. Synchronized synchronization and exact adjustments of the injector mechanical rack are critical to maintaining rated engine horsepower and proper cylinder balance.

Lubrication System Capacity: 25.0 liters (6.6 U.S. gallons) refill capacity. Configuration: Wet sump system utilizing a gear-driven oil pump. Components: Incorporates an engine oil cooler sealed with specialized O-rings and integrated piston cooling jets that receive pressurized oil directly from the main block gallery to cool the piston crowns.

Cooling System Capacity: 28.0 liters (7.4 U.S. gallons) for the core engine block. Configuration: Forced liquid-cooling circuit driven by a belt-driven water pump. Operation: Coolant circulates around the dry liners in the cylinder block and channels through the cylinder head before passing through the thermostat housing to the radiator or heat exchanger.

General Technical Data

Engine Specifications

Engine Model ............... Caterpillar 3116
Engine Type ............... 4-cycle inline 6-cylinder liquid-cooled diesel
Number of Cylinders ............... 6
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 4.13 (105.0)
Engine Stroke, in (mm) ............... 5.00 (127.0)
Displacement, cu.in (L) ............... 402 (6.6)
Rated Engine Power (Truck), hp (kW) ............... 170-250 (127-186)
Rated Engine Power (Industrial), hp (kW) ............... 140-215 (104-160)
Rated Engine Power (Marine), hp (kW) ............... 150-300 (112-224)
Rated Engine Speed, rpm ............... 2200-2600
Peak Torque ............... 600-900 Nm (443-664 lb-ft) at 1400-1600 rpm
Aspiration Type ............... Turbocharged and turbocharged aftercooled
Operating Speed ............... 2000-2600 rpm
Idle Speed ............... 600-700 rpm
Compression Ratio ............... 16.0:1-17.0:1
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 ............... Belt-driven, centrifugal
Air Cleaner Type ............... Dry two-stage
Starting System ............... Electric Starter
Electrical System ............... 12V or 24V
Alternator Rating, Amps ............... 55-120

Fuel System

Fuel System ............... Mechanical Unit Injectors (MUI)
Fuel Pump Type ............... Gear-type, transfer
Governor Type ............... Mechanical
Injection Pressure, bar ............... 1000
Fuel Type ............... Diesel Fuel

Dimensions and Weight

Overall Length, in (mm) ............... 41-45 (1050-1150)
Overall Width, in (mm) ............... 31-35 (780-880)
Overall Height, in (mm) ............... 33.5-35.5 (850-900)
Dry Weight, lbs (kg) ............... 1500 (680)

Maintenance Data

Service Information

Thermostat begins opening ............... 82C (180F)
Thermostat fully open ............... 95C (203F)
Cooling system pressure ............... 70-90 kPa (10-13 psi)
Operating oil pressure ............... 300-450 kPa (44-65 psi)
Idle oil pressure ............... 100-150 kPa (15-22 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-4, CG-4, CI-4, or higher
Engine Oil Capacity, qts (L) .................. 27.3-29.4 (25.0-28.0)
Coolant Capacity, qts (L) ............... 29.4 (28.0)

Service Intervals

Change oil and filter ............... Every 250 hours
Replace fuel filters ............... Every 500 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) ................ 4.1348-4.1364 (105.025-105.065)
Crankshaft Journal Outside Diameter, in (mm) ................ 3.4996-3.5004 (88.890-88.910)
Crank Pin Outside Diameter, in (mm) ................ 2.7555-2.7563 (69.990-70.010)
Crankshaft End Play, in (mm) ................ 0.0030-0.0100 (0.076-0.254)
Intake Valve Stem Outside Diameter, in (mm) ................ 0.3130-0.3138 (7.950-7.970)
Exhaust Valve Stem Outside Diameter, in (mm) ................ 0.3122-0.3130 (7.930-7.950)
Intake Valve Guide Inside Diameter (Installed), in (mm) ................ 0.3155-0.3167 (8.013-8.043)
Exhaust Valve Guide Inside Diameter (Installed), in (mm) ................ 0.3155-0.3167 (8.013-8.043)
Intake Valve Stem to Guide Clearance, in (mm) ................ 0.0017-0.0037 (0.043-0.093)
Exhaust Valve Stem to Guide Clearance, in (mm) ................ 0.0025-0.0045 (0.063-0.113)
Intake Valve Spring Free Length, in (mm) ................ 2.463 (62.56)
Exhaust Valve Spring Free Length, in (mm) ................ 2.463 (62.56)
Intake Cam Height, in (mm) ................ 2.6457 (67.200)
Exhaust Cam Height, in (mm) ................ 2.5694 (65.263)
Piston Pin Outside Diameter, in (mm) ................ 1.5746-1.5748 (39.995-40.000)
Piston Pin to Piston Bore Clearance, in (mm) ................ 0.0003-0.0011 (0.008-0.028)
Top Ring Side Clearance, in (mm) ................ 0.0031-0.0047 (0.080-0.120)
Second Ring Side Clearance, in (mm) ................ 0.0024-0.0040 (0.060-0.100)
Oil Ring Side Clearance, in (mm) ................ 0.0016-0.0032 (0.040-0.080)
Top Ring End Gap, in (mm) ................ 0.0157-0.0256 (0.400-0.650)
Second Ring End Gap, in (mm) ................ 0.0098-0.0197 (0.250-0.500)
Oil Ring End Gap, in (mm) ................ 0.0098-0.0197 (0.250-0.500)

Tightening Torque Specs

Cylinder Head Bolts ............... 170-190 Nm (125-140 lb-ft)
Main Bearing Bolts ............... 200-230 Nm (148-170 lb-ft)
Connecting Rod Bolts ............... 110-130 Nm (81-96 lb-ft)
Flywheel Bolts ............... 180-210 Nm (133-155 lb-ft)
Crankshaft Pulley Bolts ............... 350-400 Nm (258-295 lb-ft)
Oil Drain Plug ............... 40-55 Nm (30-41 lb-ft)
Injector Hold-Downs ............... 25-30 Nm (18-22 lb-ft)

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• Caterpillar Engines Specs
  
• Cat 3064 Specs
  
• Cat 3064T Specs
  
• Cat 3066 Specs
  
• Cat 3114 Specs
  
• Cat 3116T Specs
  
• Cat 3116TA Specs
  

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