The Heads
The high-temperature aluminum cylinder heads include a single overhead camshaft to operate four valves per cylinder. The cams are chain-driven and use hydraulic lash adjustment. Some of the photos in the DOE/Cummins documents appear to show injectors mounted inside the valve covers that would help keep the engines quiet. All the parts of the heads are designed so they can be assembled before they are attached to the block. As mentioned earlier, the EGR system is cast into the heads to minimize the size of the engines and reduce the chances of exhaust leaks. Exhaust gases sent to the manifolds are routed through exhaust passages that are built into the heads which take gases up to the crossover manifold that leads to the turbo.
The block uses parent bored...
The block uses parent bored cylinders and a four-bolt main caps. The V-6 includes a balance shaft that is mounted in the center of the V under the injection pump.
The Block
The cast-iron blocks are designed to be strong and incorporate accessories common with current gasoline engines to reduce the costs of the diesel option in SUV and 1/2-ton applications. The alternator, water pump, oil pump, an aluminum stacked plate oil cooler, A/C compressor, and the vacuum pump are mounted either to the block, the heads, or the front engine cover. The oil filter is found near the bottom of the block at the front of the engine next to the pump and close to the oil pan.
Low-Ash Oil
Like all '07 emissions-compliant diesel engines with a DPF, the Cummins V-6 and V-8 will need to use CJ-4 low-ash oil. This prevents the DPF from becoming clogged, its more resistant to heat, and produces less sludge and soot than conventional diesel blends.
ULSD (Ultra-Low Sulphur Diesel)
Anything over 15ppm sulphur content will ruin the new Cummins V-engines. It's a fact of life for any truck using piezo injectors and a DPF, but ULSD will be your only choice at public pumps by the time trucks with these engines hit the streets. In fact, you may already be using ULSD-check the pump next time you fill up.
The Bottom Line
The 4.2L V-6 and 5.6L V-8 engines that Cummins developed in cooperation with the Department of Energy look like a home run. They are strong, yet efficient, and they are very clean. Costs and noise have been taken into consideration and are likely to be the two biggest challenges to the success of these engines in the SUV and 1/2-ton marketplace. Who knows what fuel prices will be when these engines are available (hopefully, by 2010), so the superior fuel mileage may be enough to convert the spark-pluggers.
We can't predict what people will think in a few years, but we can't wait to see diesel engines in SUVs and 1/2-ton trucks. Just like the authors of the DOE/Cummins reports, we believe: "There is a path to market for the light truck diesel."
The "Old" Inline-Six?
We're sure there are a few people out there who are wary of these new V-engines and the effect they may have on the future of the venerable and beloved Cummins inline engine. Don't worry, the ISB will be A-OK, it will just displace 6.7L instead of 5.9L, will run on only ULSD, and will come with a DPF.