The legendary Caterpillar 3406E, often referred to as the 1lw Cat Motor, roared onto the scene in 1993 as Cat’s first fully electronically controlled engine. This groundbreaking powerplant, utilizing diesel as coolant in its ECM, dominated the heavy-duty truck market until its successor, the C-15, emerged in 1998.
The 1LW CAT Motor: A Powerhouse in its Prime
The 3406E marked a pivotal moment in trucking history, becoming the first 14-15 liter inline six-cylinder engine to surpass the 500 horsepower mark. Its arrival ignited the “horsepower wars” of the mid to late 90s, solidifying Caterpillar’s position as a power leader. This engine quickly became a favorite for Peterbilt, propelling Cat-powered trucks to nearly 90% of the company’s sales by the end of the decade.
Decoding the 1LW CAT Engine Specs
The 3406E boasted a diverse range of horsepower and torque ratings, tailored to various applications and transmissions. Notable examples include the Paccar-exclusive 455 HP variant, found only in Peterbilt and Kenworth trucks, and the later-released 550 HP version, requiring significantly larger radiators for efficient cooling. Interestingly, the 550 HP rating with 1650 lb-ft of torque was specifically designed for Allison transmissions and 15-speed gearboxes, while 10, 13, and 18-speed transmissions received an upgraded 1850 lb-ft torque rating.
1LW CAT: Fleet vs. Normal Ratings
The 3406E was offered in two distinct performance categories: Fleet and Normal. Fleet ratings were governed at 1800 RPM with peak horsepower at 1600 RPM, prioritizing fuel efficiency for large trucking operations. Normal ratings, governed at 2100 RPM with peak horsepower at 1800 RPM, delivered higher top-end performance. Peak horsepower typically exceeded advertised horsepower by 15 HP, except for the 550 HP variants, which produced 550 HP at 1800 RPM and 525 HP at 2100 RPM. Peak torque for most ratings occurred at 1200 RPM, with the lower torque 550 HP variant peaking at 1100 RPM.
1LW CAT Performance: Clutch, Jake Brake, and Cruise RPM
Clutch engagement torque varied from 747-940 lb-ft for lower horsepower ratings, increasing to 1000 lb-ft for ratings at or above 435 HP. The Jake Brake’s effectiveness peaked between 1700-2100 RPM, providing substantial braking power. Recommended cruise RPM fell within the 1450-1550 RPM range across all ratings. Idle speed served as an indicator of governed RPM, with 650 RPM for Fleet ratings and 750 RPM for Normal ratings. A complete list of ratings, including horsepower, torque, governed RPM, and idle speed, can be found in the original documentation.
Cost and Considerations for the 1LW CAT
The 3406E commanded a premium price compared to Cummins engines of similar ratings, reflecting Caterpillar’s reputation for robust construction and advanced technology. Drivers were encouraged to utilize adaptive automatic transmissions to fully understand the power band of each specific engine rating.
1LW CAT Sound and Availability
This engine’s distinct sound has been meticulously recreated in simulations, accurately capturing the nuances of its two-speed engine fan clutch and wastegate turbo. The availability of the 3406E in various truck models reflects its historical presence as a factory option or popular choice for glider kits. A comprehensive list of compatible truck models, ranging from Ford and Freightliner to Kenworth, Peterbilt, Volvo, and White, can be found below.
Conclusion: The Enduring Legacy of the 1LW CAT Motor
The Caterpillar 3406E, affectionately known as the 1LW CAT motor, left an indelible mark on the trucking industry. Its power, performance, and advanced technology set new standards for heavy-duty diesel engines. While production ended in 1998, the 1LW remains a highly regarded engine, remembered for its contribution to the evolution of trucking power.
