Chrysler flathead engine#Straight-6

Chrysler introduced a straight-four in 1926 when the Maxwell Motor Corporation was re-organised into the Chrysler Corporation in 1925.{{Cite book | title = Chrysler Engines, 1922-1998 | first = Willem L. | last = Weertman | publisher = SAE International | location = Warrendale, PA | isbn = 978-0-7680-1642-0 }} Initially used by Chrysler, the straight-four was fitted to Plymouth cars and Dodge light trucks beginning in 1929, lasting in production through 1933.

The original version displaced {{cvt|3044|cc|cuin|1|disp=flip}} and produced 38 hp (28 kW). This was only produced in 1926, with displacement reduced to {{cvt|2791|cc|cuin|1|disp=flip}} for 1927 and 1928. Power was initially rated the same but was upped to 45 hp (34 kW) during the 1928 model year.

After the introduction of the Plymouth brand in 1929, the base engine was subjected to a major redesign and enlarged to {{cvt|175.4|cuin|cc|1}} with the power rating remaining the same. It was also used in Dodge light trucks in 1929–1930. The engine was enlarged again to {{cvt|3213|cc|cuin|1|disp=flip}} in 1930 with 48 hp (36 kW), for 1931 with 56 hp (42 kW), and 1932 with 65 hp (48 kW) for Plymouth only; Dodge continued with the 48 hp (36 kW) from 1931 to 1933. A small-bore version was developed for export markets in 1931, with a narrower bore which brought the RAC rating down from 21 to 15.6 hp. For 1932 the bore was reduced further, bringing the tax horsepower rating to just beneath 15.5.

Chrysler did not offer a four-cylinder engine again until 1981 with the Chrysler 2.2 & 2.5 engine used in the Chrysler K platform.

File:1951 Plymouth 3.6-liter 'six' in a Cranbrook.jpg]]

The first straight-6 was the B-Model (seven main bearings) and introduced in 1924 with the first Chrysler Corporation production, the B70. An upscale version designated E-Model equipped the new Chrysler Imperial E80 in 1926, and a downscale one named H-Model followed in 1927 (Chrysler Series 70). After the purchase of Dodge Brothers Company in 1928, Chrysler Corporation had five straight-6s in production with the addition of the Victory and Senior Dodge Brothers engines.

So, with the introduction of the new Desoto brand in 1929, came a new and cheaper to produce six cylinder, the K-Model, with four main bearings and deep skirts. By mid-1930, it partially replaced the previous engines in varying displacements on passenger cars, in conjunction with an all-new straight-8 engine. Only the Imperial's engine remained in production for the Dodge Trucks' 2-ton Models F-40 & K-50, 3-ton models F-60 & K-70, 2 & 3-ton Special, buses from 1930 to 1934-35. To replace these two engines, a new and very large six cylinder was launched in late 1936 (331 cu. in.), which grew to 413 cu in and was las used in the C-3 Series{{what|date=February 2025}} in 1956.

In 1932, the Ford flathead V8's launch shook up the market, expanding the demand for larger engines to even entry-level brands. A new straight-6 for Plymouth (PC/PD) and Dodge (DP/DQ) came in production in 1933, known as the "23 in block", featuring a shallow skirt and a {{clarification needed span|text=head desk length of 580 mm,|reason=What is a "head desk length"; please provide an appropriate WP link, and/or a reliable citation.|date=February 2025}} followed by a larger ("25 in block" – 640 mm) variant for Desoto (S3) and Chrysler Royal (C16) in 1937, marking the K-Model end everywhere but in Canada. When Chrysler established an engine foundry in Windsor, Canada, in 1938, it was decided to only use the long block for all Canadian-built engines. These engines received a trailing "C" in their designation. Thanks to judicious bore and stroke dimensioning, the Canadian 201- and 218-cubic inch engines had nearly identical displacement to their American cousins.Lee, p. 375

Beginning in 1938, the {{cvt|201.33|cuin|cc|0|adj=ri0}} straight-six was used in Massey Harris's Model 101 tractor (later known as the 101 Super). It continued to be used by Massey until 1940, when it was supplanted by the {{cvt|217.76|cuin|cc|0|adj=ri0}}.{{cite book |last=Pripps |first=Robert N. |year=2001 |title=The big book of Massey tractors |isbn=1-55192-423-4 |publisher=Raincoast Books |location=Vancouver |oclc=46991918}} In 1940, Chrysler's {{cvt|242|cuin|cc|0}} straight six went into Massey's 201 Super, which lasted until 1942.

During World War II, the {{cvt|250.6|cuin|cc|0|adj=ri0}} flathead six was used as the basis for the Chrysler A57 multibank tank engine.{{cite book |title=Standard Catalog of U.S. Military Vehicles |last=Berndt |first=Thomas |year=1993 |publisher=Krause Publications |isbn=0-87341-223-0 |page=193 }}

The last automotive use of the Chrysler flathead straight-six was in 1968 (in the Dodge Power Wagon WM300, its last year of production, which used the 251 cu in variant Standard Catalog of American Light-Duty Trucks). It was replaced throughout Chrysler products by the much more efficient OHV Slant-6 released in 1960, which appeared in most Dodge trucks starting in 1961. The flathead remained in production until the early 1970s for industrial and agricultural use.{{Citation needed|date=March 2011}}

File:1937 Chrysler Airflow.jpg]]

The new straight-8 engine is largely based on the six-cylinder engine that appeared on the Desoto Model K. It has five main bearings,{{what|date=February 2025}} the central one being wider. When the engineers had to rebore the cylinders to 3-1/2 inches, the space between each pair of cylinders was modified.{{clarification needed|reason=To what?|date=February 2025}} This applies to all blocks with the same bore.

In the case of the Imperial (CG, CH), then Custom imperial (CL, CW), a new 9 main bearing straight-8 engine was developed, equipped with a two-barrel downdraft carburetor. From the CW model, the cylinder head is made of aluminum. It also powered the Dodge Trucks G-80 models (1931-1934) and Fargo buses (1930-1932).

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• List of Chrysler engines

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Flathead

Category:Straight-six engines

Category:Gasoline engines by model

Category:Straight-four engines