Cat 3408 Engine Specs

by Erik DevaneyUpdated June 22, 2023

The Cat 3408 is a high-speed, industrial engine from Caterpillar Incorporated that is no longer in production. According to Pro Vehicles, the 3408 can power a variety of vehicles, including yachts, ships, loaders and trucks. Workers use trucks with 3408 engines for hauling heavy loads to and from construction sites as well as for hauling coal out of mines.


The Cat 3408 is a diesel internal combustion engine. A report on the Georgia State University website notes that, unlike an Otto cycle engine, which uses a spark plug to ignite gasoline fuel, a diesel engine uses compression to generate intense heat that causes the combustion of diesel fuel. Gasoline fuel and diesel fuel are both derivatives of crude oil.

Electrical Power

As Pro Vehicles notes, the Cat 3408 can generate a maximum electrical power of 266 kilowatts (kW). A single kW is equal to 1,000 watts.


Horsepower is a unit of work. The Cat 3408 can achieve a maximum of 447 to 520 horsepower. One unit of horsepower is equal to 550 foot-pounds per second, or 745.7 watts.

Operation Duration

The Cat 3408 has a life expectancy of approximately 16,000 operating hours, which is a little less than two years if the engine were run non-stop.


According to the BoatDiesel website, the Cat 3408 is an eight-cylinder engine. This means the engine has eight piston chambers, each of which has a corresponding piston that pumps up and down inside of it. In general, the more cylinders an engine has, the more powerful the engine.


Displacement is another indicator of an engine’s power. The Cat 3408 has a displacement of 18.0 liters, which is equivalent to 18,000 cubic centimeters or 1,098.4 cubic inches.


Before igniting fuel and causing pistons to fire, internal combustion engines must take in oxygen to mix with the fuel. While some types of engines rely on the natural flow of air for this purpose, the Cat 3408 utilizes a specialized compressor known as a turbocharger. The turbocharger pumps higher amounts of air into cylinders during combustion, allowing for a higher power output.

Fuel Injection

The Cat 3408 relies on a hydraulically actuated, electronically controlled unit injector (HEUI) system for transporting diesel fuel from a storage tank to its eight cylinders. The HEUI system functions by pulling fuel from the tank with a pump that generates both low and high pressure. After the fuel passes through a filter, water separator and heating apparatus, the system sends fuel into the cylinders using a series of injectors.

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