Exactly what is a Hemi?
The folks at Grogan's Towne examine this historic engine
It all started in 1951 when Chrysler introduced a line of V8 engines with an usual shape to their combustion chambers. Unlike previous designs, these new engines had cylinder heads that were molded in the shape of a dome or "hemisphere." Enthusiasts soon started calling the powerful new engines "Hemis" and the name stuck. Later in the 1950s, the word became a brand name trademarked by Chrysler Corporation.
Hemispherical heads
What's unique about the engine is that the dome head design allowed engineers to place the exhaust and intake valves on opposite sides of each combustion chamber. This lent itself to broad valve surfaces and large head cooling passages, all of which led to a cooler-running, highly-efficient engine. In fact, because the engine was so efficient, Chrysler engineers could design in higher compression ratios than usual to create additional torque and horsepower.
Unfair competition?
The Hemi engine really came into its own in the mid-1950s. During this time, Chrysler models such as Dodge (Red Ram Engine), Chrysler (FirePower Engine) and DeSoto (FireDome Engine), adopted the Hemi design. The public loved these Hemi-powered cars because of their high horsepower but some of the other car manufacturers claimed the brilliant design wasn't fair! In 1964, stock Chrysler Hemi engines were so powerful that they were initially banned from NASCAR races as "unfair competition".
Complexity = cost
The downside to the Hemi design was complexity. Because Hemi engines had two rocker shafts per head, the engine had a relatively complicated valve train. While this lent itself to powerful engines, it cost Chrysler a lot more money to make them. Unfortunately, this led to the phasing out of the original Hemi engine design and the return of earlier wedge head designs.
The Hemi lives on!
Today, we see many vehicles with Hemi engines. In some cases, these engines have hemispherical heads but they don't have the complicated valve trains of the 1950s Chrysler Hemis. However, the general principle of the dome-shaped cylinder head lives on!
Located in Toledo, OH, Grogan's Towne is your Hemi headquarters!
For more information on Stellantis performance cars and their legendary Hemis, contact the friendly sales staff at Grogan's Towne Chrysler, Dodge, Jeep, Ram.
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