Hear a former CAT engineer discuss the advantages of inline-sixes over V8s for demanding tasks.

      Earthmoving Legacy Center via YouTube

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      In the workplace, the discussion isn't “gas versus diesel.” While there are moments when a gasoline engine may be appropriate, diesel is generally the preferred option for larger jobs. Rather than debating which fuel handle to select, the more popular discussion revolves around engine configuration. Some manufacturers advocate for “V” cylinder designs, and their supporters echo that sentiment, while others vouch for inline engines. So, which is superior?

      Jim Coles, a former Caterpillar engineer and experienced semi-truck dealer, firmly supports the inline-six. He started his career at Caterpillar in 1966 before opening a Peterbilt dealership in 1973, expanding his network to 18 locations over the next four decades. While I may sound biased, I find Coles’ expertise more credible than the average poster in Facebook truck forums.

      Coles recently made an appearance at the Earthmoving Legacy Center in Elkader, Iowa, where a 25-minute interview was posted to their YouTube channel. In the video, he reflected on his formative years at Caterpillar, during which they were creating specialized engines, many intended for off-highway applications. The company favored the inline-six for its natural balance and simpler cooling. Additionally, when it was time to add new components to these engines, such as turbochargers or emissions systems, they provided a much better foundation to work with.

      Coles specifically discussed the Caterpillar 3406, a 14.6-liter (or 893-cubic-inch) engine family produced for over 30 years, from 1973 to 2007. Internally, it was referred to as the VITEL, which stands for “vehicle industrial truck engine line.” Whether used in earth-moving machinery, stationary setups, marine contexts, semi-trucks, or other applications, it was highly regarded.

      “Caterpillar and others did explore V-type engines,” Coles remarked, referencing the 90-degree RM180 and the 3408. “However, V vs. inline configurations have always represented a more compromised design.”

      Earthmoving Legacy Center via YouTube

      “Today, you’ll see inline-sixes delivering up to 1,100 hp,” Coles noted. “All the other V engines once found in the market—like the 903 Cummins, the 555 Cummins, the 3208 Caterpillar, the 8V71, and 8V92 Detroits—are now obsolete. No one is manufacturing V engines anymore, and rightfully so.”

      While Coles may not have directly said, “Eight in a vee, you squat to pee,” he clearly aligns with the notion that “six in a row makes it go.” So, if you own a Cummins and find yourself in a debate with Duramax or Power Stroke enthusiasts in the comments section, make sure to share this insight with them.

      Why the Inline-Six Won | Former Caterpillar Engineer Jim Coles

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