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G3520/G3520BStandard Equipment

Air Inlet System
  • Axial Flow Air cleaner
  • Cleanable
  • Intermediate-duty with service indicator

Control System
  • ADEM A3 with integrated electronic throttle control
  • Control panel

Cooling System
  • Two-stage charge air cooling
  • Thermostats and housing
  • Engine-driven jacket and aftercooler water pump
  • Stainless steel aftercooler cores

Exhaust System
  • Dry exhaust manifolds
  • Dry exhaust elbow

Flywheels and Flywheel Housings
  • SAE No. 00 flywheel
  • SAE No. 00 flywheel housing
  • SAE standard rotation

Fuel System
  • 7-50 psi gas supply
  • Fuel system is sized for 800 to 1200 btu/scf (31.5 to 47.2 MJ/Nm3)
  • Electronic fuel metering valve
  • Gas pressure regulator
  • Gas shutoff valve (GSOV)

Ignition System
  • ADEM A3

Lubrication System
  • Crankcase breather — top mounted
  • Oil cooler
  • Oil filter — RH
  • Oil pan — 143 gal
  • Drain valve
  • Oil sampling valve
  • Turbo oil accumulator

Mounting System
  • Engine mounting rails - 330.2 mm (13 in) industrial-type

Power Take-Offs
  • Front housing — two-sided
  • Front lower LH, RH, and upper RH accessory drives

  • Paint — Cat yellow
  • Crankshaft vibration damper and guard
  • CSA Certification, Class 1 Division 2, Group D - electrical system and instrumentation - includes ADEM A3 and control panel

G3520/G3520BOptional Equipment

Air Inlet System
  • Round air inlet adaptors

Charging System
  • Charging alternator - CSA approved 24V, 65 A

Cooling System
  • Flexible connections

Exhaust System
  • Flexible fittings
  • Flange and expander

Fuel System
  • Gas filter

  • Communications module

Lubrication System
  • Lubricating oil
  • Oil bypass filter
  • Air prelube pump

Power Take-Offs
  • Front stub shaft
  • Pulleys
  • Double damper

Protection System
  • Explosion relief valves
  • Secondary GSOV

Starting System
  • Air starting motor with controls (90 psi or 150 psi)
  • API B16.3 compliant piping
  • Jacket water heater
  • Barring group

  • Special paint
  • Torsional vibration analysis

EU Certification
  • EEC DOI certification

  • Factory commissioning


The Cat® G3520 and G3520B Industrial Gas Engines are offered in the following ratings: 1104 bkW (1480 bhp) @ 1200 rpm and 1286 bkW (1725 bhp) @ 1400 rpm. These ratings are NSPS site compliant capable with customer-supplied aftertreatment. For specific emission information, please consult your local Cat Dealer.

Power Rating

Minimum Power 1480.0 BHP 1104.0 bkW Less
Maximum Power 1725.0 BHP 1286.0 bkW Less
Frequency 1200-1400 rpm 1200-1400 rpm Less


Bore 170 mm (6.7 in) 170 mm (6.7 in) Less
Stroke 190 mm (7.5 in) 190 mm (7.5 in) Less
Displacement 86.3 L (5263 in³) 86.3 L (5263 in³) Less
Engine Configuration Engien - Continuous Engien - Continuous Less

Engine Dimensions - Approximate

Height 2385 mm (94 in) 2385 mm (94 in) Less
Length 4180 mm (164 in) 4180 mm (164 in) Less
Weight - Net Dry 11168 kg (24622 lb) 11168 kg (24622 lb) Less
Width 1755 mm (69 in) 1755 mm (69 in) Less


Ratings are NSPS site compliant capable with customer-supplied aftertreatment. For specific emission information, please consult your local Cat Dealer.

Engine Design

  • Built on G3500 LE proven reliability and durability
  • Ability to burn a wide spectrum of gaseous fuels
  • Robust diesel strength design prolongs life and lowers owning and operating costs
  • Broad operating speed range at lower site air densities (high altitude/hot ambient temperatures)
  • Higher power density improves fleet management
  • Quality engine diagnostics
  • Detonation-sensitive timing control for individual cylinders

Ultra Lean Burn Technology (ULB)

ULB technology uses an advanced control system, a better turbo match, improved air and fuel mixing, and a more sophisticated combustion recipe to provide: - Lowest engine-out emissions - Highest fuel efficiency - Improved altitude and speed turndown - Stable load acceptance and load rejection

Advanced Digital Engine Management

ADEM A3 engine management system integrates speed control, air/fuel ratio control, and ignition/detonation controls into a complete engine management system. ADEM A3 has improved: user interface, display system, shutdown controls, and system diagnostics.

Full Range of Attachments

Large variety of factory-installed engine attachments reduces packaging time.


Every Cat engine is manufactured to stringent quality standards in order to assure customer satisfaction.

World-class Product Support Offered Through Global Cat Dealer Network

  • Scheduled maintenance, including SOSSM sample
  • Customer Support Agreements (CSA)
  • Caterpillar Extended Service Coverage (ESC)
  • Superior dealer service network
  • Extended dealer service network through the Cat Industrial Service Distributor (ISD) program