What is a Chrysler Hemi?
A: The Chrysler Hemi engines, known by the trademark Hemi, are a series of I6 and V8 gasoline engines built by Chrysler with hemispherical combustion chambers.
How many different types of Hemi engines have been built by Chrysler for automobiles?
A: Three; the first (known as the Chrysler FirePower engine) from 1951 to 1958, the second from 1964 to 1971, and the third beginning in 2003.
Although Chrysler is most identified with the use of "Hemi" as a marketing term, many other auto manufacturers have done what?
A: Incorporated similar designs.
During the 1970s and 1980s, Chrysler also used the Hemi name for what foreign made item?
A: Their Australian-made Hemi-6 Engine.
A hemispherical cylinder head ("hemi-head") gives an efficient combustion chamber with an excellent surface-to-volume ratio, with minimal heat loss to the head, and allows for two what?
A: Large valves.
However, a hemi-head allows no more than how many valves per cylinder?
A: Two, and these large valves are necessarily heavier than in a multi-valve engine.
The intake and exhaust valves lie on opposite sides of the chamber and necessitate what type of head design?
A: A "cross-flow" head design.
Since the combustion chamber is a partial hemisphere, a flat-topped piston would yield too low a what?
A: Compression ratio unless a very long stroke is used.
To attain the desired compression ratio the piston crown is domed to protrude into the head at top dead center, resulting in a combustion chamber in the shape of what?
A: The thick peel of half an orange.
Where does the hemi-head design place the spark plug?
A: At or near the center of the chamber to promote a strong flame front.
If the hemi-head hemisphere is of equal diameter to the piston, there is minimal squish for proper turbulence to do what?
A: To mix fuel and air thoroughly.
Thus, hemi-heads, because of their lack of squish, are more sensitive to what?
A: Fuel octane rating.
A given compression ratio will require a higher octane rating to avoid what?
A: Pre-detonation in a hemi engine than in some conventional engine designs such as the wedge and bathtub.
The hemi head always has intake and exhaust valve stems that point how?
A: In different directions, requiring a large, wide cylinder head and complex rocker arm
This adds to the overall width of the engine, limiting what?
A: The vehicles in which it can be installed.
Chrysler developed their first experimental hemi engine for what?
A: The Republic P-47 Thunderbolt
The XIV-2220 engine was an inverted V16 rated at how much horsepower?
A: 2,500 hp (1,860 kW).
In addition to the aircraft engine, Chrysler and Continental worked together to develop the air-cooled AV-1790-5B V12 Hemi engine used in what?
A: The M47 Patton tank.
Chrysler applied their military experience with the hemispherical combustion chamber to their first overhead-valve V8 engine, released under what name?
A: Under the name FirePower, not "Hemi," in 1950 for the 1951 model year.
The first version of the FirePower engine had what displacement?
A: 331 cu in (5.4 L) and produced 180 bhp (134.2 kW).
Eventually, three of the four Chrysler divisions had its own what?
A: Versions of the FirePower engine, with different displacements and designations, and having almost no parts in common.
This lack of commonality was due in part to the three engine versions using different what?
A: Bore pitches (the center-to-center distance between adjacent cylinders).
Chrysler and Imperial called their versions the what?
A: The FirePower.
DeSoto called theirs the what?
A: The FireDome.
Dodge had a smaller version, known as what?
A: The Red Ram.
Only Plymouth didn't have a version, instead retaining what?
A: The Dodge poly-head engines: there was no Plymouth hemi engine until the 1964 426.
Collectively, the 1951-'58 Hemi engines are now commonly referred to as what?
A: First-generation Hemi engines.
How can the group can be identified?
A: By the rear-mounted distributor and the spark plugs in a row down the center of wide valve covers.
A Chrysler-powered Cunningham C5-R won its class in what year?
Cunningham switched away from these designs in 1959 when Chrysler temporarily abandoned the hemispherical concept in favor of what?
A: The wedge-head B engine until 1964.
This first FirePower engine, used from 1951 to 1955, has a bore of 3.8125 in and a stroke of 3.625 in for a piston displacement of what?
A: 331 cu in (5.4 L).
The bore pitch, shared by all Chrysler FirePower engines, was what?
A: 4.5625", the largest of any 1st generation hemi engines.
Most used a two-barrel carburetor and produced 180 bhp (134 kW), with the famous exception of the 1955 Chrysler C-300 equipped with dual Carter WCFB four-barrel carburetors and rated at how much horse power?
A: 300 hp.
The 300B engine was rated at 340 bhp (254 kW), while the New Yorker and Imperial 354 engine configuration produced how much horsepower?
A: 280 bhp (209 kW).
For the 300B an optional 355 hp (265 kW; 360 PS) version was available, making it the first what?
A: American V-8 to be rated at one horsepower per cubic inch.
Note that was before 1972, horsepower was what?
A: SAE gross.
After 1972, horsepower is what?
A: SAE net.
For 1958, Chrysler offered the 392 in what two configurations?
A: 325 bhp (242 kW) with 9.25:1 compression and 345 bhp (257 kW) with 10:1 compression, both with a single four-barrel carburetor.
A dual four-barrel version of the 392 available in the 1957-58 Chrysler 300C & 300D cars was rated at how much horsepower?
A: 375 bhp (280 kW).
What was an extremely rare option available on the 1958 300D?
A: The Bendix "Electrojector" fuel injection, with which the 392 was rated at 390 bhp (291 kW).
Due to reliability problems with the primitive onboard
computer which controlled the injection system, however, 15 of the 16 300D cars built with the fuel injection option were what?
A: Recalled and retrofitted with carburetors.
In the late 1950s and early 1960s who found the 392 to be a formidable engine?
A: Drag racers.
In 1952, DeSoto introduced its version of the FirePower with a bore of 3.625 in (92.08 mm) and stroke of 3.344 in (84.94 mm), for what displacement?
A: A displacement of 276.1 cu in (4.5 L).
The bore pitch, shared by all DeSoto FirePower engines, was what?
A: 4.3125 in (109.54 mm).
The DeSoto engine was enlarged for 1956 to what displacement?
A: 329.9 cu in (5.4 L).
Bore was the same as the 291 at 3.72 in (94.5 mm), but stroke was increased to 3.80 in (96.5 mm) and a taller (raised-deck) block was used.
What was the largest DeSoto engine for 1957?
A: The DeSoto Adventurer offering 344.6 cu in (5.6 L) with square bore and stroke dimensions of 3.80 inches.
The DeSoto Adventurer used dual Carter WCFB four-barrel carburetors for a rating of what horsepower?
A: 345 bhp (257 kW), again producing one horsepower per cubic inch.
When was Dodge's Hemi was introduced?
A: In 1953 as the Red Ram.
When did Dodge introduce the 241.3 cu in (4.0 L) engine?
A: In 1953.
With a low compression ratio of 7.0:1 (in 1953 and for the 1954 Meadowbrook), the 241 produced how much horsepower?
A: 140 bhp (104 kW).