People who know cars know the Hemi engine. Even those who are not familiar with vehicles have been enticed with advertisements for cars and trucks with an engine bearing the Hemi name. Those ads alone have been enough to make car and truck owners dream about feeling the rumble of the engine and hearing the roar when they drive.
The hemispherical design of the combustion chamber in the engine is what gives the Hemi its name. This design has been proven to create more thermal and volumetric efficiency than other engine designs. While the design of the combustion chamber is popular enough that many companies use the hemispherical chambers, the actual name Hemi was trademarked by Chrysler in the early 1950’s. Before that, it was known within the company as a Double Rocker Head engine due to the pushrod design.
Because Chrysler trademarked the name Hemi and has used it zealously in advertising over the years, many people assume that Chrysler invented the Hemi. In fact, the original designs for this type of engine were used in the first horseless carriages as early as 1901. (Photo: Hemi Chamber, Wikipedia)
Chrysler began using the Hemi engine in its vehicles in the early 1950’s when they wanted to introduce vehicles with more power that did not have an increase compression. The early Hemi engines had little in common with the engines that were to come, but were still considered amazingly powerful for their time. The size of the engine was marginally smaller than future Hemi engines, but the power was much different. For example, the 331ci Hemi V-8 boasted only 180hp at 4000rpm as opposed to the 425-500hp created by the 426 Hemi.
The spark plugs were in the same place, and the basic valve train assembly was the same, but they were not even called Hemi engines. Chrysler gave the engines special names to entice the buyers to pay for the upgraded engine when they ordered their new vehicles. The Red Ram, Firedome and Firepower engines, as Chrysler called them, were available on a few vehicles. The Hemi was offered by Plymouth, Imperial, Dodge, DeSoto, and Chrysler.
One of the most famous Hemi engines is the 426 Hemi. Its design was innovative for many reasons. The ability to get the maximum amount of power from an engine is partially dependent on how the heads are bolted to the block in the engine. Chrysler added a fifth head bolt to the engine block in order to give their engine that extra power. Also, due to the placement of the pushrods in the 426 Hemi, the bolts were moved to the underside of the engine in order to keep them from interfering with the Hemi’s power. (Photo by Hugo, Flickr)
In the beginning, the 426 Hemi was more of a racing engine than an engine meant for passenger cars. NASCAR first saw the Hemi engine at the Daytona 500 in 1964. That year the Hemi engines came in first, second, third, and fourth place and completely shocked the world of racing. NASCAR eventually decided that the only way that Chrysler would be allowed to use a Hemi engine in a NASCAR race would be for Chrysler to ‘street’ them. In other words, Chrysler had to mass-produce the new engines and offer them in regular passenger vehicles to be allowed to race using them. Chrysler sat out the 1965 NASCAR season, but had met all of NASCAR’s demand in time for the 1966 season by offering the Hemi in 1966 Dodges Chargers, Dodge Coronets and Plymouth Belvederes. According to Chrysler, approximately 10,000 of these vehicles were produced with the 426 Hemi inside.
Chrysler brought the Hemi back in more recent years. In 2001, Chrysler announced that it was producing a Hemi V-8 for their Dodge trucks and the Jeep Grand Cherokee for that model year. The lure of a Dodge Ram with more power was enticing, and the heavily advertised come-back was a huge draw for many truck buyers.
Lately, the 2011 Dodge Ram 1500 has garnered applause from several places. Most notable was the praise from US News. The smooth ride, comfortable interior and precision handling put this truck far above others in its class. The powerful Hemi V-8 blows the competition away altogether. (Photo by SLacroix –Photographie, Flickr)
The remake of the Dodge Challenger is another popular vehicle featuring the Hemi engine. Model year 2008 was the third time that Dodge introduced the Dodge Challenger. (Photo by Dodge Challenger1, Flickr)