Why Dodge & Ram Still Use Iron Engine Blocks In Some Vehicles

The primary Iron Age flickered out a millennium or two ago, but its automotive equivalent continues to be going strong. Well, if not strong, it’s at the very least still going. Dodge, Ram, and other automakers still feature iron blocks because the foundations for his or her engines — despite a growing trend toward putting more aluminum in today’s cars and trucks.

Aluminum actually began getting used within the auto industry way back to 1899, when Heinrich Durkopp showed an aluminum-bodied sports automotive on the Berlin Motor Show. And it has been utilized in many other ways through the years as well. Remember when Ford began making an enormous deal about aluminum being practical for a truck bed?

But counting on aluminum for engine blocks really took off when the 1961 Buick Special went on sale with a 215-cubic-inch V8. The Special had aluminum not only for the block, but for the heads and intake manifold, too. The goal was saving weight, and replacing iron with aluminum within the block gets the job done: Automakers can reduce how heavy an engine is by some 40% through the use of it. The outcomes can include higher efficiency and performance, too, since the motor is not pushing around as many kilos. And yet, iron’s high strength and low price deliver benefits that also delay today.

Generally speaking, iron blocks are stronger than their aluminum counterparts, letting them delay higher to internal pressures and deliver more horsepower. Iron can also be so much cheaper than aluminum: High-grade iron ore will set you back about $105 per metric ton. The identical amount of aluminum is currently above $2,600, a rise of greater than 5% for the reason that starting of June. With no signs of tariffs ending, and aluminum so crucial to so many automotive parts, it’s no wonder cars are about to get a heap dearer.

After all, iron does have some flaws, starting with that previously mentioned weight problem that comes from the actual fact iron being roughly 2.9 times as dense as aluminum — meaning that a given chunk of aluminum weighs 2.9 times lower than the same-sized piece of iron. Aluminum can also be much less liable to corrosion than iron.

Something else to bear in mind is that some recent engine blocks are made out of compacted graphite iron (CGI). That is iron mixed with graphite, together with another elements, to create an engine-block material that might be lighter than forged iron while delivering higher performance than aluminum. It looks as if the decision continues to be out on these items, since Cummins, which had been providing CGI diesel engines for HD Ram trucks, is reportedly switching back to a standard iron block in the longer term for a more refined driving experience. The block stays CGI for 2025, though.

The heavy-duty Rams offer that CGI-blocked Cummins engine in the shape of a 6.7-liter turbocharged inline-6 turbo diesel, and, on the gas side, a 6.4-liter Hemi V8 with a cast-iron block. For Ford SuperDuty trucks, cast-iron blocks are present in the 7.3-liter and 6.8-liter V8 gas engines, while a pair of turbocharged 6.7-liter PowerStroke diesels provides CGI blocks. It’s much the identical deal for General Motors. GM’s Chevrolet and GMC heavy-duty trucks might be configured with each 6.6-liter turbodiesel and gas V8 engines with iron blocks.

That each one is sensible, as commercial-grade trucks can profit plenty from the higher strength of iron blocks. They’re pretty rare in light-duty vehicles, nevertheless, and are mostly used for high-performance rides which might be also seeking to maximize engine strength.

The previously mentioned Hemi, as an illustration, has a cast-iron block, as do the 5.7-liter and 6.2-liter versions available under the hood of the 2025 Dodge Durango. With Dodge perhaps bringing back the Hemi to the Charger, and confirming the Hemi is back for the 2026 Ram 1500, those brands will soon boast quite a few cast-iron blocks. Ford has fewer iron-block options, but compacted graphite iron is utilized in the block, but not the heads, of Ford’s 2.7-liter EcoBoost V6, which is a top engine for the Bronco, amongst others. The General seems to have ironed out any issues with aluminum, using that lightweight stuff now for nearly all light-duty models.