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Caterpillar 3114 Engine

The Caterpillar 3114 is a mid-displacement, 4-stroke cycle, inline four-cylinder diesel engine engineered primarily for off-highway equipment, industrial, marine, and generator set applications. Introduced as part of Caterpillar's 3100 engine series, it features a heavy-duty cast-iron engine block and shared core components with its six-cylinder counterpart, the 3116. It is recognized in workshop environments for its structural reliability, mechanical simplicity, and entirely gear-driven timing train.

The 3114 utilizes a Mechanically Controlled Unit Injector (MUI) fuel system, eliminating high-pressure external fuel lines. Delivery and Transfer: A mechanical fuel transfer pump draws fuel from the supply tank, routing it through a water separator and a high-efficiency spin-on fuel filter. Manifold and Injectors: Fuel is delivered into a low-pressure fuel manifold cast directly into the cylinder head, which continuously supplies fuel to each individual unit injector. Excess fuel exits via a return line back to the tank, acting as a cooling medium for the injectors. Actuation and Injection: The unit injectors combine fuel pumping, high-pressure metering, and atomization into a single component located over each cylinder. Injector plungers are mechanically actuated via pushrods and rocker arms driven directly by the engine camshaft. Governing: Fuel metering is synchronized by an internal mechanical governor linked to a common control rack that regulates the effective stroke of each injector plunger simultaneously.

The engine utilizes a full-pressure lubrication system supplied by a gear-type oil pump driven directly by the crankshaft gear. Flow Path: Oil is drawn from the oil pan through a suction screen, routed through an integral water-cooled oil cooler, and forced into a spin-on full-flow oil filter base. Distribution: Filtered oil supplies the main oil gallery in the block to lubricate crankshaft main bearings, connecting rod journals, camshaft bearings, and front gear train. Component Cooling: Piston cooling jets are installed at the bottom of the main gallery to spray oil onto the underside of the pistons.

The system is a closed-loop, liquid-forced circulation design regulated by a single bypass thermostat. Circulation: A gear-driven centrifugal water pump draws coolant from the radiator or heat exchanger and forces it into the engine block. Coolant flows around the cylinder liners, upward through the cylinder head to cool the valve ports and unit injector sleeves, and into the thermostat housing. Temperature Regulation: When coolant temperature is below the fully open rating, the thermostat diverts the fluid directly back to the water pump intake via a bypass line. At operating temperature, the regulator opens to channel hot coolant to the external radiator or heat exchanger.

General Technical Data

Engine Specifications

Engine Model ............... Caterpillar 3114
Engine Type ............... 4-cycle inline 4-cylinder liquid-cooled diesel
Number of Cylinders ............... 4
Cylinder Arrangement ............... In-line
Engine Bore, in (mm) ............... 4.13 (105.0)
Engine Stroke, in (mm) ............... 5.00 (127.0)
Displacement, cu.in (L) ............... 268 (4.4)
Rated Engine Power (NA), hp (kW) ............... 90-105 (67-78)
Rated Engine Power (Turbo), hp (kW) ............... 110-130 (81-96)
Rated Engine Speed (NA), rpm ............... 2200
Rated Engine Speed (Turbo), rpm ............... 2200
Peak Torque ............... 508 Nm (375 lb-ft) at 1400-1600 rpm
Aspiration Type ............... Naturally aspirated or Turbocharged
Operating Speed ............... 2200-2800 rpm
Compression Ratio ............... 17.0:1-18.5:1
Firing Order ............... 1-3-4-2
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 element
Starting System ............... Electric Starter
Electrical System ............... 12V or 24V
Alternator Rating, Amps ............... 45-85

Fuel System

Fuel System ............... Unit Injectors (MUI/EUI)
Fuel Pump Type ............... Gear-type, transfer
Governor Type ............... Mechanical/Electronic
Fuel Type ............... Diesel Fuel

Dimensions and Weight

Overall Length, in (mm) ............... 37.4-45.3 (950-1150)
Overall Width, in (mm) ............... 25.6-29.5 (650-750)
Overall Height, in (mm) ............... 33.5-41.3 (850-1050)
Dry Weight, lbs (kg) ............... 880-1100 (400-500)

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 ............... 240-450 kPa (35-65 psi)
Idle oil pressure ............... 100-140 kPa (15-20 psi)
Intake Valve Clearance, in (mm) ............... 0.015 (0.38)
Exhaust Valve Clearance, in (mm) ............... 0.025 (0.64)

Engine Oil and Coolant

Engine Oil Type .................. SAE 10W-30, 15W-40
API Service Classifications ......................... CH-4/SJ or higher
Engine Oil Capacity, qts (L) .................. 11.6 (11.0)
Coolant Capacity, qts (L) ............... 15.2 (14.5)

Service Intervals

Change oil and filter ............... Every 250 hours
Replace fuel filters ............... Every 250 hours
Inspect air filter ............... Every 50 hours
Change coolant ............... Every 2 years
Valve-lash adjustment ............... Every 3000 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) ................ 4.1348-4.1358 (105.025-105.050)
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) ................ 0.3134-0.3140 (7.961-7.977)
Exhaust Valve Stem Outside Diameter, in (mm) ................ 0.3128-0.3134 (7.945-7.961)
Intake Valve Guide Inside Diameter (Installed), in (mm) ................ 0.3154-0.3166 (8.012-8.042)
Exhaust Valve Guide Inside Diameter (Installed), in (mm) ................ 0.3154-0.3166 (8.012-8.042)
Intake Valve Stem to Guide Clearance, in (mm) ................ 0.0014-0.0032 (0.035-0.081)
Exhaust Valve Stem to Guide Clearance, in (mm) ................ 0.0020-0.0038 (0.051-0.097)
Intake Valve Spring Free Length, in (mm) ................ 2.4640 (62.59)
Exhaust Valve Spring Free Length, in (mm) ................ 2.4640 (62.59)
Intake Cam Height, in (mm) ................ 1.8524-1.8681 (47.050-47.450)
Exhaust Cam Height, in (mm) ................ 1.8213-1.8370 (46.260-46.660)
Piston Pin Outside Diameter, in (mm) ................ 1.4997-1.5000 (38.092-38.100)
Piston Pin to Piston Bore Clearance, in (mm) ................ 0.0003-0.0007 (0.008-0.018)
Top Ring Side Clearance, in (mm) ................ 0.0024-0.0043 (0.060-0.110)
Second Ring Side Clearance, in (mm) ................ 0.0024-0.0041 (0.060-0.104)
Oil Ring Side Clearance, in (mm) ................ 0.0015-0.0035 (0.038-0.089)
Top Ring End Gap, in (mm) ................ 0.0138-0.0217 (0.350-0.550)
Second Ring End Gap, in (mm) ................ 0.0157-0.0256 (0.400-0.650)
Oil Ring End Gap, in (mm) ................ 0.0100-0.0220 (0.250-0.560)

Tightening Torque Specs

Cylinder Head Bolts ............... 160 Nm (118 lb-ft)
Main Bearing Cap Bolts (Vertical) ............... 190 Nm (140 lb-ft)
Main Bearing Cap Cross Bolts ............... 75 Nm (55 lb-ft)
Connecting Rod Cap Bolts ............... 120 Nm (89 lb-ft)
Flywheel Housing-to-Block Bolts ............... 75 Nm (55 lb-ft)
Flywheel-to-Crankshaft Bolts ............... 115 Nm (85 lb-ft)
Injector Clamp Bolt ............... 35 Nm (26 lb-ft)
Oil Pan Bolts ............... 27 Nm (20 lb-ft)

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

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