Chevrolet Straight-6 engine
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The Chevrolet inline 6 of the 1930s through 1970s was the base engine in many popular cars, including the Chevrolet Camaro.
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[edit] 1929
The first mass-produced GM straight-6 was introduced in 1929 on Chevrolet cars and trucks, replacing the company's straight-4. It was produced through 1936.
[edit] 194
It was 194 in³ (3.2 L) in size and produced 50 hp. This engine used a forged steel crankshaft with three bearings and cast iron pistons. Bore and stroke was 3.3125 in (84.14 mm) by 3.75 in (95.25 mm). The 194 was shared with Chevrolet and GMC trucks for 1935 and 1936.
A balanced crankshaft was introduced for 1932, while a higher (5.2:1) compression ratio upped output to 60 hp. A new cylinder head two years later pushed output to 80 hp.
[edit] 181
A 181 in³ (3.0 L) version was used by Chevrolet and GMC trucks in 1935 and 1936.
[edit] 207
A 207 in³ (3.4 L) variant was used by Chevrolet and GMC trucks in 1934, 1935 and 1936.
[edit] 1937
The next-generation Chevrolet straight-6 was introduced in 1937 and phased out in 1953. Both were also shared with Chevrolet's trucks.
[edit] 216
This engine displaced 216 in³ (3.6 L) with a 3.5 in (88.9 mm) bore and the same 3.75 in (95.25 mm) stroke. A four-bearing crankshaft was added, along with 6.5:1 compression pistons, for 85 hp. A new cylinder head in 1941 bumped output to 90 hp, and 6.6:1 compression gave the 1949 model 92 hp. This generation did not use pressurized oiling.
[edit] Stovebolt Era
[edit] 235
A new 235 in³ (3.9 L) version was added in 1950 to complement the new Powerglide automatic transmission. It added hydraulic lifters, and pressurized lubrication was introduced in 1953. Two versions were used in 1953 - a solid-lifter version with 123 hp and the hydraulic-lifter 136 hp version for Powerglide use. The latter engine continued in production through 1962.
This engine was also used by GMC Truck.
[edit] 261
A 261 in³ version of the hydraulic-lifter engine was produced from 1954 through 1962.
This engine was also used by GMC Truck until they introduced their own GMC V6 engine.
[edit] Generation 3
Chevrolet's third-generation Straight-6 was introduced in 1962 and produced through 1988. This generation was lighter in mass although the dimension were similar to the previous generation Stovebolts - the difference between the Stovebolt and the third generation sixes is the cast-in Chevrolet V8 bell housing pattern (similar to Chevrolet small block, big blocks, and the W-series). With the addition of the bellhousing redesign - transmission bellhousings (for manual transmissions) and automatics between Chevrolet V8s and sixes are interchangeable - this also includes the starter motors between both engines.
Although still considered a truck motor, the first usage was in the newly-introduced 1962Chevy II; the following year, Chevrolet passenger cars used this powerplant until 1978 (1979 for Camaros and Novas). Chevrolet/GMC trucks, which previously used the Stovebolts (235 and 261), also used some members of this family from 1963 through 1984, as did Pontiac in 1964 and 1965. There was also a straight-4 version of this engine.
By the mid-1970s, the compact V-design (e.g. Buick 231) led to the phaseout of inline sixes in passenger cars where the inline six continued for usage in trucks and vans until 1988. It is common to find a Buick 3.8 and/or Chevrolet 4.3 in a mid-1980s GM RWD passenger cars with an elongated fan shroud since the motor's positioning is farther back than the inline six.
[edit] 153
The 153 in³ (2.5 L) 153 was a straight-4 version of the family and was only used by Chevrolet. This engine is entirely different from the later 151 in³ Iron Duke, but the two are often confused today. That name was never used for this engine when it was produced.
Applications:
- 1962-1969 Chevy II
- 1967-1971 Postal Jeep
[edit] 194
The 194 in³ (3.2 L) 194 was shared between Chevrolet and GMC trucks.
Applications:
- 1962-1967 Chevy II
- 1964-1967 Chevrolet Chevelle
- 1965-1966 Studebaker Commander, Daytona ('66 only), Cruiser and Wagonaire (built by McKinnon Industries in Canada)
[edit] 215
Pontiac's 215 (1964-1965) is documented elsewhere.
[edit] 230
The 230 displaced 230 cubic inches (3.8L). It was also used by Chevrolet and GMC trucks.
This engine was used on the following vehicles:
- 1963-70 Chevrolet
- 1965-1968 Checker Marathon
- 1965 Chevrolet El Camino
- 1966 Studebaker Commander, Wagonaire, Daytona and Cruiser
- 1967 Chevrolet Camaro
[edit] 3.8
The Pontiac 3.8 was a special SOHC version of the standard 230 (3.8L) I6. An optional W53 version on the Firebird produced 215hp.
This engine was used on the following vehicles:
- 1967 Pontiac Firebird
- 1967 Pontiac Tempest Sprint coupe
[edit] 250
The stroked 250 version produced 175hp for Chevrolet and GMC. Between 1975 - 1984, an integrated cylinder head was produced, with one-barrel intakes for passenger cars, and two-barrel intakes for trucks after 1978.
During the mid-1970s, the Buick 231 and Chevrolet V6-90 (basically a variant of the Chevrolet small block V8) was replacing the Chevrolet 250 for use in passenger cars and light duty trucks/vans. It would be GM's final inline six (along with the Chevrolet 292) until the introduction of the GM Atlas engine in late 2001.
This engine was used on the following vehicles:
- 1966-1984 Chevrolet (passenger cars to 1979, trucks/vans to 1984)
- 1968-1969 Pontiac Firebird
- 1968-1969 Chevrolet Camaro
- 1969-1979 Checker Marathon
[edit] L22
The L22 was a 250 in³ (4.1 L) I6 engine produced from 1977 to 1979.
[edit] LD4
The LD4 was a 250 in³ (4.1 L) I6 engine produced from 1978 to 1978.
[edit] LE3
The LE3 was a 250 in³ (4.1 L) I6 engine produced from 1979 to 1984.
[edit] 292
The 292 was only used in Chevrolet and GMC trucks; the block deck is taller, along with a relocated passenger-side engine mount. These were produced between 1963 to 1990; production of the engine shifted to Mexico after 1984.
[edit] L25
The L25 was GM's "last" straight-6 engine, produced from 1977 to 1985. It was used in Chevrolet trucks, displaced 292 in³ (4.8 L) and produced 115 hp and 215 ft.lbf.
[edit] Atlas
In 2003, GM announced a new family of straight-6 engines, the Atlas. This engine is covered in detail on its own page.
