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Pontiac straight-6 engine
The Pontiac straight-6 engine is a family of inline-six cylinder automobile engines produced by the Pontiac Division of General Motors Corporation in numerous versions beginning in 1926.
In the 1920s Oakland Motor Car engineers designed an all new engine for their "companion" make, the Pontiac, that was introduced in 1926. It was a side-valve design with a one piece cast iron block with three main bearings. An unusual feature was that it had two separate cylinder heads that each covered three cylinders. The ignition distributor was mounted on top of the block in the gap between the heads. This engine was also used in GMC's 1927 T-10 and 1928 T-11 (their lightest trucks) as well as their next lightest truck, the T-19, beginning in 1928. Development of the engine shared characteristics with the Oldsmobile Straight-6 engine, as GM worked together to develop the engine for Pontiac combined with the resources of GM-Northway Motor and Manufacturing Division.
This engine displaced 186.7 cu in (3.1 L) with a bore and stroke of 3.25 in × 3.75 in (82.6 mm × 95.3 mm) and was rated at 40 hp (30 kW; 41 PS) at 2400 rpm when it was introduced. The compression ratio was 4.8:1.
In 1929, the "split head" Pontiac six was increased in displacement to 200 cu in (3.3 L). The horsepower rating increased to 60 hp (45 kW; 61 PS) @ 3000 rpm. Compression was increased slightly to 4.9:1. The "split-head" six was discontinued by Pontiac at the end of the 1932 model year. Pontiac offered only eight-cylinder engines during 1933 and 1934. GMC also switched to the 200 cubic inch engine in 1929, using it into early in the 1933 model year.
In 1935, Pontiac re-introduced their six-cylinder engine, as a 208 cu in (3.4 L) straight-6. The 208 was produced in 1935 and 1936. It was a side-valve design with a timing chain, as was popular at the time. This engine featured a conventional one piece cylinder head, and the distributor was moved to the side of the block. The number of main bearings was increased to four. Like the Pontiac Straight-8 engine it also featured full-pressure oiling and insert type precision main and rod bearings. These two latter features greatly increased longevity and durability especially under high speed conditions.
The 223 was a side-valve engine, and used a timing chain. The 223 cu in (3.7 L) straight-6 was used in Pontiac automobiles (1937–40) and GMC trucks (1938 only).
The 239 cu in (3.9 L) straight-6 was similar in design to previous sixes. It was used from 1941 through 1954 only in Pontiac automobiles.
A 215 cu in (3.5 L) overhead valve straight-6 was produced in 1964 and 1965 but was not an original Pontiac design. Sometimes confused with the Buick designed and built 215 cu in (3.5 L) aluminum V8 that Pontiac had used in the two years prior, the "Pontiac 215" was an adaptation of Chevrolet's 194 cu.in. inline 6 currently produced and the new 230 cu in (3.8 L) overhead valve Turbo-Thrift straight-6. Quite different from Pontiac's previous straight-6s, it had a smaller bore 3.75 in (95.3 mm) than the 15 cu in (250 cc) larger Chevrolet engine and a Chevy bellhousing, but its flywheel/flexplate bolt pattern was Pontiac's.
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Pontiac straight-6 engine
The Pontiac straight-6 engine is a family of inline-six cylinder automobile engines produced by the Pontiac Division of General Motors Corporation in numerous versions beginning in 1926.
In the 1920s Oakland Motor Car engineers designed an all new engine for their "companion" make, the Pontiac, that was introduced in 1926. It was a side-valve design with a one piece cast iron block with three main bearings. An unusual feature was that it had two separate cylinder heads that each covered three cylinders. The ignition distributor was mounted on top of the block in the gap between the heads. This engine was also used in GMC's 1927 T-10 and 1928 T-11 (their lightest trucks) as well as their next lightest truck, the T-19, beginning in 1928. Development of the engine shared characteristics with the Oldsmobile Straight-6 engine, as GM worked together to develop the engine for Pontiac combined with the resources of GM-Northway Motor and Manufacturing Division.
This engine displaced 186.7 cu in (3.1 L) with a bore and stroke of 3.25 in × 3.75 in (82.6 mm × 95.3 mm) and was rated at 40 hp (30 kW; 41 PS) at 2400 rpm when it was introduced. The compression ratio was 4.8:1.
In 1929, the "split head" Pontiac six was increased in displacement to 200 cu in (3.3 L). The horsepower rating increased to 60 hp (45 kW; 61 PS) @ 3000 rpm. Compression was increased slightly to 4.9:1. The "split-head" six was discontinued by Pontiac at the end of the 1932 model year. Pontiac offered only eight-cylinder engines during 1933 and 1934. GMC also switched to the 200 cubic inch engine in 1929, using it into early in the 1933 model year.
In 1935, Pontiac re-introduced their six-cylinder engine, as a 208 cu in (3.4 L) straight-6. The 208 was produced in 1935 and 1936. It was a side-valve design with a timing chain, as was popular at the time. This engine featured a conventional one piece cylinder head, and the distributor was moved to the side of the block. The number of main bearings was increased to four. Like the Pontiac Straight-8 engine it also featured full-pressure oiling and insert type precision main and rod bearings. These two latter features greatly increased longevity and durability especially under high speed conditions.
The 223 was a side-valve engine, and used a timing chain. The 223 cu in (3.7 L) straight-6 was used in Pontiac automobiles (1937–40) and GMC trucks (1938 only).
The 239 cu in (3.9 L) straight-6 was similar in design to previous sixes. It was used from 1941 through 1954 only in Pontiac automobiles.
A 215 cu in (3.5 L) overhead valve straight-6 was produced in 1964 and 1965 but was not an original Pontiac design. Sometimes confused with the Buick designed and built 215 cu in (3.5 L) aluminum V8 that Pontiac had used in the two years prior, the "Pontiac 215" was an adaptation of Chevrolet's 194 cu.in. inline 6 currently produced and the new 230 cu in (3.8 L) overhead valve Turbo-Thrift straight-6. Quite different from Pontiac's previous straight-6s, it had a smaller bore 3.75 in (95.3 mm) than the 15 cu in (250 cc) larger Chevrolet engine and a Chevy bellhousing, but its flywheel/flexplate bolt pattern was Pontiac's.