Diesel-powered firetruck served department since 1982…
January 18, 2019 | AutoGuide
“To me, I think it’s very significant… It’s never been done in the truck market,” noted Rod Romain, chief engineer of the 2019 Ram Heavy Duty range. “This is a first; 1,000 pound-feet was a big barrier and it’s a lot of torque.”
That mountain of twist is provided by the optional Cummins inline-six diesel, a legendary powerplant offered, once more, in two potencies. Displacing a husky 6.7-liters, in standard form it delivers 370 horsepower and 850 pound-feet of torque, but in high-output guise, it’s rated 400 and 1,000, respectively.
One of the most important enablers of that torque figure is a redesigned cylinder block. While the bore and stroke remain the same as in last year’s Cummins, for 2019 it’s now cast of compacted graphite iron, an advanced material that’s much more durable than conventional iron. This metal is also better at attenuating noise and vibration, plus it allows for thinner, lighter castings with no reduction in strength.
The venerable Cummins diesel’s cylinder head has been redesigned, sporting new exhaust valves and upgraded rocker arms. This engine’s oil and water pumps have also been redesigned, plus it’s been fitted with a brand-new fuel-delivery system, one that operates at 29,000 psi (2,000 bar) for enhanced performance and efficiency. Filling its six holes are new, lower-friction pistons and upgraded forged connecting rods riding on reworked bearings.
But don’t think engineers skimped or cut corners with the 2019 Ram Heavy Duty’s “base” diesel engine. “All of the benefits and all of the upgrades that are in a 1,000 pound-feet motor, those are in the 850 [as well],” explained Romain. This includes the fancy new block, enhanced cooling system, improved crankshaft and more.