Caterpillar 3304

Engine Specifications & Applications of the Caterpillar 3304 Engine

Overview of the Caterpillar 3304 Engine

The Caterpillar 3304 is a heavy-duty, 4-cylinder diesel engine designed for durability, longevity, and versatility. Originally introduced in the 1960s and used extensively through the 1980s and 1990s, the 3304 engine has proven itself in countless applications—from construction equipment to marine auxiliary power.

As part of Caterpillar’s 3300-series family, which also includes the 3306 and 3304B variants, the 3304 features a mechanically governed direct injection system, a wet-sleeve design, and an option for turbocharging depending on configuration. With its reputation for mechanical reliability and low-maintenance operation, the CAT 3304 remains popular today in fleets committed to overhaul and parts replacement rather than new engine purchases.

Even though the engine is no longer produced by Caterpillar, the aftermarket parts ecosystem remains strong—especially through suppliers like Diesel Pro Power, which specialize in premium-quality 3304 components.

Caterpillar 3304 Engine Technical Specifications

Specification	Details
Engine Model	Caterpillar 3304
Configuration	Inline 4-cylinder, 4-stroke diesel
Displacement	7.0 Liters (425 cubic inches)
Bore x Stroke	4.75 x 6.00 inches (121 mm x 152 mm)
Compression Ratio	16:1 (varies by version)
Fuel System	Direct Injection (Mechanical)
Aspiration	Naturally Aspirated or Turbocharged
Cooling System	Water-cooled
Rated Horsepower	95–150 HP (Turbocharged up to 170+ HP)
Max Torque	~420 lb-ft @ 1,400–1,800 RPM
Operating Speed	1800–2200 RPM
Dry Weight	Approx. 1,400–1,600 lbs (depending on version)
Emissions Compliance	Pre-Tier 1 (non-EPA regulated)

Notable Engine Variants

• 3304NA – Naturally aspirated for standard-duty applications

• 3304T – Turbocharged for improved power and torque

• 3304DI – Direct injection for enhanced fuel efficiency

• 3304B – Later version with performance and emissions improvements

• 3304 Marine Engine – Equipped for auxiliary or propulsion use with seawater cooling and corrosion protection

Key Features of the Caterpillar 3304 Engine

• Simple mechanical design—ideal for field service and rebuilds

• Wet replaceable cylinder liners—extend engine service life through in-frame overhauls

• Turbocharging options for improved output without increasing engine size

• Reliable direct injection system for consistent power delivery

• Proven performance across thousands of installations worldwide

These advantages make the 3304 a popular engine platform for operators seeking long-term ROI through rebuild and parts replacement, rather than costly upgrades or replacements.

Applications of the Caterpillar 3304 Engine

Thanks to its robust design and flexible power output, the Caterpillar 3304 found widespread use in multiple industries. Today, it remains in operation in marine, construction, agricultural, and power generation applications, especially where simplicity and serviceability are key.

1. Construction & Heavy Equipment

The 3304 was widely installed in Caterpillar and non-Caterpillar construction equipment, where torque and uptime were essential.

Equipment Powered by CAT 3304:

• CAT 920, 930, 950 wheel loaders

• CAT 112 and 120 graders

• CAT 931, 933, 951 track loaders

• CAT D4 and D5 dozers (early models)

• CAT 225 and 235 hydraulic excavators

• Air compressors, trenchers, and skid units

In these applications, the 3304 offered dependable torque, ease of service, and long hours between overhauls. Diesel Pro Power supports these machines with rebuild kits, injectors, turbos, and more.

2. Marine Auxiliary and Light Propulsion

Though less common in full propulsion, the turbocharged Caterpillar 3304T was used in smaller vessels and as an auxiliary engine.

Marine Use Cases:

• Marine generators (up to 75–100 kW)

• Hydraulic power units for cranes and winches

• Bilge, ballast, and fire pump engines

• Light-duty commercial boats (harbor tugs, crew boats)

• Auxiliary drive systems for refrigeration and deck gear

Diesel Pro Power stocks marine-ready raw water pumps, heat exchangers, thermostats, and gaskets tailored to 3304 marine configurations.

3. Industrial Equipment and Power Units

The Caterpillar 3304 excelled as a standalone power source for various stationary and mobile units in industrial operations.

Typical Installations:

• Portable water pumps and flood control equipment

• Drilling rigs and hydraulic power packs

• Generator sets (up to 100 kW depending on configuration)

• Oilfield service units

• Railroad maintenance equipment

Its compact size, mechanical simplicity, and consistent performance made it an excellent choice in harsh environments.

4. Agricultural Equipment

Many early agricultural tractors and irrigation systems used the 3304, especially in large-scale farming operations or for powering auxiliary equipment.

Agricultural Applications:

• Diesel-powered irrigation pumps

• Grain elevators and conveyors

• Stationary belt-driven equipment

• Early Challenger and Massey Ferguson tractors (select models)

Diesel Pro Power supports agricultural users with affordable overhaul kits, fuel components, and cooling system replacements.

Additional Resources

Marine CAT 3304 Component Maintenance Life