The Tale of Two Diesels

In 1919 a man named Clessie Cummins had formed a company building stationary diesel engines. Cummins engines were effective and started to be respected and used in marine applications too. Clessie was convinced the diesel had viability for more purposes that anyone had given it credit for, so he evangelized. He had spent much of the 1930s showboating his concepts, even entering Cummins diesels in the Indianapolis 500 as early as 1931.

In 1938, one of GM’s premier engineers, a guy named Charles Kettering, managed to convince the powers-that-be to let him develop a new diesel engine. Kettering had conviction that the diesel was a good solution for automotive/trucking applications, but believed existing engines were too heavy and too underpowered. He wanted to develop a lightweight diesel engine that was practical in those applications, and so the General Motors Diesel Engine Division was born, later becoming Detroit Diesel.

Both men, brilliant and undeterred, worked their ideas into fruition. And while WWII put a kink in plans, it also provided an impetus for more development. So by the mid 1950s, diesel engines were becoming more common in bigger trucks. Eventually other engine manufacturers such a Mack and Caterpillar started developing their road-going diesels.

The early 1960s had everyone in trucking looking at diesels, and the big grumbling 6-cylinder gasoline engines that had the market foothold up to the mid-1950s were becoming harder to find. The diesels were proving more durable, more powerful and more economical than the gas engines.

As recently as the early 1970s it was the Detroit 238 and Cummins 250 that ruled the streets in fleet tractors. Both had their adherents and detractors and neither was perfect, but they were functional, got double the fuel economy the gas engines doing same work and were comparatively easy to work on. Of note, the 238 and 250 happened to be the horsepower ratings of these engines, so while they went down the road, doing so at modern legal weight required bushel baskets of gear-changes. A guy running an old Detroit had his right hand welded to the shifter; he was constantly downshifting to keep the engine in the sweet-spot.

Fast forward to the 70s-80s. More and more weight required more power. Owner operators with baloney-sliced 6” chrome stacks and Christmas trees worth of clearance lights on their trucks were buying big-bore 500HP engines like hotcakes. Farmers had started buying diesel pickups for durability and economy but needed more power to pull their stock trailers. Before long the horsepower wars were raging in the light truck diesel market too. By 1995 pickups with diesels consistently had more power than the fleet tractor-trailers of the 1960s.

But fleet tractors were doing an about-face in the ‘90s; engines got smaller and had more conservative power ratings. Fleet operators were concerned about economy, and they were finding that the custom-tailored programming available on the new electronic mid-bore diesels was actually allowing them to run nearly as well as the old big-bores, all the while getting continually better economy.

Light truck diesels aren’t there yet. While it is true that a few the 400+ HP monster pickups are really used for pulling paying loads, most live out their lives under individuals doing less strenuous activities, like pulling a 16’ bass boat or maybe a camper trailer. Drivers always like more power, but don’t always need more power. Maybe it’s time for light-truckers to ratchet-back the baloney sliced, dual-piped, chrome air-cleanered bravado just a hair?                                                                                                                                                                                               © 2014 D.W. Williams. All rights reserved