G3408C Low Emissions Gas Compression Engine

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Engine Design

 • Improved 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


Meets U.S. EPA Spark Ignited Stationary NSPS Emissions for 2007/08

Lean Burn Engine Technology

Lean-burn engines operate with large amounts of excess air. The excess air absorbs heat during combustion reducing the combustion temperature and pressure, greatly reducing levels of NOx. Leanburn design also provides longer component life and excellent fuel consumption.

Cat® Electronic Ignition System (EIS)

Detonation sensitive timing protects the engine against detonation damage. Higher voltage and longer spark duration mean easier starts, fewer misfires, and smoother operation. Diagnostic codes help pinpoint cylinder and component of interest. Spark plug maintenance codes identify spark plug condition

Ease of Operation

 • Deep sump oil pan has a larger capacity for normal 750-hour oil change intervals
 • Side covers on block allow for inspection of internal components

Full Range of Attachments

Large variety of factory-installed engine attachments reduces packaging time


Every engine is full-load tested to ensure proper engine performance.

Gas Engine Rating Pro

GERP is a web-based program designed to provide site performance capabilities for Cat natural gas engines for the gas compression industry. GERP provides engine data for your site’s altitude, ambient temperature, fuel, engine coolant heat rejection, performance data, installation drawings, spec sheets, and pump curves.

Product Support Offered Through Global Cat Dealer

More than 2,200 dealer outletsCaterpillar factory-trained dealer technicians service every aspect of your petroleum engineCat parts and labor warrantyPreventive maintenance agreements available for repair-before-failure optionsS•O•SSM program matches your oil and coolant samples against Caterpillar set standards to determine:
 - Internal engine component condition
 - Presence of unwanted fluids
 - Presence of combustion by-products
 - Site-specific oil change interval

Over 80 Years of Engine Manufacturing Experience

Over 60 years of natural gas engine productionOwnership of these manufacturing processes enables Caterpillar to produce high quality, dependable products.
 - Cast engine blocks, heads, cylinder liners, and flywheel housings
 - Machine critical components
 - Assemble complete engine

Web Site

For all your petroleum power requirements, visit www.cat.com/oilandgas.

Engine Specifications
Maximum Rating 317 bkW (425 BHP)
Emissions NSPS Site Compliant Capable or Non-regulated
Displacement 18 l (1099 inu00b3)
Minimum Rating 317 bkW (425 BHP)
Compression Ratio 8.5:1
Aspiration Turbocharged-Aftercooled
Rotation from Flywheel End Counterclockwise
Flywheel and Flywheel Housing SAE No. 0
Flywheel Teeth 136
Weight - Dry 2245 kg (4950 lb)
Oil Change Interval 750 hours
Ignition, Protection Cat EIS
Stroke 152 mm (6 in)
Bore 137 mm (5.4 in)
Capacity for Liquids
Cooling System 54.9 l (14.5 gal (US))
Lube Oil System - Refill 147.63 l (39 gal (US))

Standard Equipment

  • Air Inlet System
    • Air cleaner — single element with service indicator
  • Control System
    • Electronic governor
    • Air/fuel ratio control
  • Cooling System
    • Thermostats and housing
    • Jacket water pump
    • Aftercooler water pump
    • Aftercooler core
  • Exhaust System
    • Watercooled exhaust manifolds
    • Dry exhaust elbow
  • Flywheel & Flywheel Housing
    • SAE No. 0 flywheel
    • SAE No. 0 flywheel housing
    • SAE standard rotation
  • Fuel System
    • Gas pressure regulator (1.5 to 5 psi gas supply required)
    • Natural gas carburetor
  • Ignition System
    • Cat Electronic Ignition System (EIS) with detonation sensitive timing
  • Instrumentation
    • Service meter
  • Lube System
    • Crankcase breather — top mounted
    • Oil cooler
    • Oil filter — RH
    • Oil pan — deep sump
    • Oil filler — RH in valve cover and RH dipstick
  • Mounting System
    • Engine supports
  • Protection System
    • Detonation sensitive timing control
    • Shutoff
  • General
    • Paint — Cat yellow
    • Crankshaft vibration damper and pulleys
    • Lifting eyes
    • Cylinder block inspection covers

Optional Equipment

  • Air Inlet System
    • Air cleaner — two-stage
    • Air inlet adapter
    • Precleaner
    • Air cleaner rain cap
  • Charging System
    • Battery chargers
    • Charging alternators
    • Ammeter gauge
    • Ammeter gauge and wiring
    • Control mounting
  • Cooling System
    • Radiators
    • Blower fan and fan drives for customer suppliedradiators
    • Expansion tank
    • Heat exchangers
  • Exhaust System
    • Flexible fittings
    • Elbows
    • Flanges
    • Rain caps
    • Mufflers
    • Exhaust manifold — instrument holes at each port
  • Fuel System
    • Dual gas regulator
    • Carburetor kits
    • Fuel filter
  • Ignition System
    • CSA ignition
    • Ignition ground wiring harness
    • Power supply
  • Instrumentation
    • Alarm module
    • Gauges and instrument panels
  • Mounting System
    • Vibration isolators
  • Power Take-offs
    • Auxiliary drive pulleys
    • Enclosed clutch and clutch support
    • Front stub shaft
    • Flywheel stub shaft
    • Pulley removal
  • Protection System
    • Gas valves
    • Status control box interconnect wiring harness
  • Starting System
    • Air starting motor
    • Air pressure regulator
    • Air silencer
    • Electric start control
    • Electric starting motors — single 24V
    • Starting aids
    • Battery sets — (24V dry), cables, and rack
  • General
    • Special paint

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