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CATEGORIES (articles) > Engines > Cadillac > Cadillac V8 engine history

Cadillac V8 engine history

Cadillac was the first automobile maker to mass produce a V8 engine. The company has produced eight generations of V8s since 1914, and today is the only General Motors division to retain its own V8 design.


The Type 51 was the first Cadillac V8. Introduced in 1914, it was the standard engine for 1915 Cadillac models. It was a 90° design with an L-head (sidevalve) configuration and was water cooled. Bore was 3.125 in and stroke was 5.125 in, for a total of 314 in³ of displacement. Output was 70 hp (52 kW).

The engine was refined for 1923 with a new split crankshaft that introduced the (now standard) 90° offset for each pair of cylinders. Power was up to 83.5 hp (62 kW).

The L-Head was on the Ward's 10 Best Engines of the 20th Century list.

L-Head applications:

  • Cadillac Type 51
  • Cadillac Type 53
  • Cadillac Type 55
  • Cadillac Type 57
  • Cadillac Type 59
  • Cadillac Type 61
  • Cadillac V-63
  • Cadillac Series 341
Cadillac created a new V8, the 341, for 1928. It was a 341 in³ engine and produced 90 hp (67 kW). The same year saw the introduction of the synchromesh transmission. This engine was used in the Series 341 and 341B cars of 1928 and 1929.

From 1930 through 1935, Cadillac produced a version with an increased displacement of 353 in³ (5.8 L). This used a 3.38 in (85.7 mm) bore and 4.94 in (125.4 mm) stroke. This engine was used in the Series 353/355/355B/355C/355D and Series 10.


A 322 in³ (5.3 L) "monobloc" engine was used in 1936's Series 60. It was designed to be the company's next-generation powerplant at reduced cost from the 353 and Cadillac V12. The monobloc's cylinder heads were cast as one unit with the engine block, and it used hydraulic valve lifters for durability. This design allowed the creation of the mid-priced Series 60 line.

Bore was 3.375 in (85.7 mm) and stroke was 4.5 in (114.3 mm). This engine was modified with a 3.5 in (88.9 mm) bore for the 1936-1948 346 in³ (5.7 L) engine. This was used in the Series 60/60S/61/62/63/65/67 and 70/72/75. It was also used in tanks in World War II.


In 1937, displacement was reduced to 346 in³ for 135 hp (101 kW) to replace the LaSalle Straight-8 of 1934–1936. A smaller 322 in³ version was also introduced at 125 hp (93 kW). In the 1940s, these were paired with Cadillac's new Hydramatic automatic transmission. These engines were produced through 1948.


1962 Cadillac Series 62 390 V8 engine


For 1949, Cadillac and Oldsmobile shared a new V8 design, Olds at 303 in³ engine and Cadillac at 331 in³. This was the first OHV V8. Output was impressive at 160 hp (119 kW). The American automakers competed throughout the 1950s to produce the most powerful V8. Cadillac quickly added four-barrel carburetors and dual exhausts to their V8 models, boosting output to 250 hp (186 kW) for most by 1955. The Eldorado used twin four-barrels for 270 hp (201 kW).


Displacement was up to 365 in³ for 1956, and the 1958 Eldorado 3-2bbl version produced 335 hp (250 kW).


A longer stroke pushed displacement to 390 in³ for 1959, yielding 325 hp (242 kW), while the Eldorado six-pack reached 345 hp (257 kW).

Redesigned OHV

For the 1963 model year Cadillac updated their V8 engine, modernizing the tooling used in the production line while optimizing the engine's design. Although it shared the same layout and architecture with the 1949-vintage engine, the revised engine had shorter connecting rods and was one inch (25.4 mm) lower, 4 inches (101.6 mm) narrower, and 1.25 in (31.8 mm) shorter. The accessories (water pump, power steering pump, distributor) mounted on a die-cast aluminum housing at the front of the engine for improved accessibility. An alternator replaced the former generator. The crankshaft was cored out to make it both lighter and stronger. The revised engine was 52 lb (23.6 kg) lighter than its predecessor, for a total dry weight of 595 lb (270 kg).


For 1963 the revised engine shared the same 4.00 in (101.6 mm) bore and 3.875 (94.4 mm) stroke of its predecessor, for an unchanged displacement of 390 in³ (6.4 L). Power was unchanged at 325 hp (242.5 kW), as was torque at 430 ft·lbf (670 N-m).


For 1964 the engine was bored to 4.13 in (104.9 mm) and stroked to 4.00 (101.6 mm), raising displacement to 429 in³ (7.0 L). Power rose to 340 hp (253.6 kW) and torque to 480 ft·lbf (747.8 N-m). The 429 was used through the 1967 model year.

World's Largest

Although the modernized engine was compact and light for its displacement and output, 429 in³ represented the limit of the original architecture's expansion, and it had been surpassed by Chrysler's 440 and Lincoln's 462. As a result Cadillac introduced an all-new engine for 1968.


At introduction, the new engine had a 4.30 in (109.2 mm) bore and a 4.06 in (103.1 mm) stroke for a displacement of 472 in³ (7.7 L). It delivered 375 hp (280 kW) @ 4400 rpm, and a massive 525  ft·lbff (712 N·m) torque, produced at just 3000 rpm. The new engine was about 80 lb (36.3 kg) heavier than its predecessor. It was used through 1974.


For 1970 Cadillac stroked the V8 to 4.304 in (109.3 mm), increasing total displacement to 500 in³ (8.2L). At introduction it was rated at 400 hp (298 kW), SAE gross, and 550 ft·lbf (857 N-m) of torque. For 1971 compression was reduced to 8.5:1, reducing power to 365 hp (gross) or 235 hp (175 kW) in the new SAE ratings. By 1976, its final year, it had fallen to 190 hp (141.7 kW). It remains the largest displacement regular-production passenger car engine ever offered by a US manufacturer.

Downsized OHV

The market of the 1970s forced Cadillac to downsize its vehicles and engines. While the Cadillac Seville used a 350 in³ (5.7 L) Oldsmobile V8 engine, Cadillac also began work on smaller proprietary engines.


In 1977 Cadillac introduced a new 425 in³ (7.0 L) V8, based on the architecture of the 472, but with a smaller, 4.08 in (103.6 mm) bore and 4.06 in (103.2 mm) stroke. The new engine was also 100 lb (45.3 kg) lighter.

The 425 was offered in L33 form, with a four-barrel carburetor, producing 180 hp (134 kW) @ 4000 rpm and 320 ft·lbf (498.6 N-m) of torque at 2000 rpm, and L35 with electronic fuel injection for 195 hp (145 kW); torque was the same, but peaked at 2400 rpm.

The 425 was used through 1979 on all Cadillacs except the Seville.

368 and V8-6-4

In 1980 the 425 was replaced with the L61, which was the same basic engine de-bored to 3.80 in (96.5 mm) for a total displacement of 368.3 in³ (6.0 L). The reduction in displacement was largely an effort to meet CAFE requirements for fuel economy. Fuel injection (which would be known to GM as throttle-body injection after 1985) was now standard except for Fleetwood Limousines and Commercial Chassis.

Cadillac refers to the fuel injection system as digital fuel injection; this particular induction system was later adopted by other GM division except Oldsmobile V8s.

Power output dropped to 145 hp (108.2 kW) @ 3600 rpm and torque to 270 ft·lbf (420.7 N-m) @ 2000 rpm. This engine was standard on all Cadillacs except the redesigned Seville, where it was optional.

For 1981 Cadillac introduced what became the most notorious engine in the company's history, the V8-6-4 (L62). The 368 had not provided a significant improvement in the company's CAFE numbers, so Cadillac and Eaton Corporation devised a cylinder deactivation system that would shut off fuel to two or four cylinders in light-load conditions like highway cruising, then reactivate them when the throttle was opened. A dashboard "MPG Sentinel" gauge could show the number of cylinders in operation, or instantaneous fuel consumption (in miles per gallon). The L62 produced 140 hp (104.4 kW) @ 3800 rpm and 265 ft·lbf (412.9 N-m) @ 1400 rpm. Cadillac hailed the L62 as a technological masterpiece, and made it standard equipment across almost the whole Cadillac line (the Seville retained its standard Oldsmobile-based 5.7 L diesel V8).

While cylinder deactivation would make a comeback some 20 years later (with modernized technology), Cadillac's V8-6-4 proved to have insurmountable teething problems, both mechanically and electronically. The biggest issue was that the engine control computer was simply not fast enough or powerful enough to efficiently manage the number of cylinders in operation, so many of these engines had their variable-cylinder function disabled by dealers, leaving them with permanent eight-cylinder operation. The 368 was dropped for most Cadillac passenger cars after the 1981 model year, although the V8-6-4 remained the standard engine for Fleetwood Limousines and the carb 368 remained in the Commercial Chassis through 1984.

Aluminum OHV


A new engine was introduced for 1982, the HT-4100 (option code LT8). This engine, designed for transverse, front wheel drive applications, originally was slated for 1983 and a new line of 'downsized' Cadillac sedans. With the failure of the V8-6-4, however, and delays in the downsizing program (shared with Buick and Oldsmobile) that ultimately delayed those cars until 1985, the new V8 was rushed into production for the 1982 model year.

Like the infamous inline-four used by the Chevrolet Vega, the HT-4100 had an unusual aluminum block (with cast-iron cylinder liners) and cast-iron cylinder heads. It had a 3.465 in (88 mm) bore and a 3.307 in (84 mm) stroke for a displacement of 249 in³ (4.1 L). It initially was equipped with throttle-body fuel injection, with output of 125 hp (93 kW) @ 4200 rpm and 190 ft·lbf of torque at 2000 rpm. Since most Cadillacs still had curb weights in excess of 4,000 lb (1,814 kg), acceleration was lackluster. Early engines also had significant reliability problems, most eventually resolved.

Performance improved when the engines were used in the originally planned, lighter front-wheel drive sedans (although it was not used in the heavier limousines or the compact Cimarron).

For 1987 a more powerful version of the 4.1 L engine was introduced in the Cadillac Allante, using a different camshaft profile and roller rocker arms to reduce reciprocating weight, in addition to multiport fuel injection. This engine was rated at 170 hp (126.8 kW) @ 4300 rpm and 235  ft·lbff (319 N·m) of torque @ 3200 rpm. The 4.1 was superseded by larger-displacement engines, and ceased production after the 1988 model year.


Engineering allowed the company to begin to raise displacement and output again. A bored-out (to 92 mm) 4.5 L HT-4500 version was introduced in 1988 with 155 hp (116 kW). Various versions were built between this introduction and the end of production for this engine in 1992, including a high-output LW2 with multiport fuel injection version for the Allante which produced 200 hp (149 kW) and 270  ft·lbff (366 N·m).


An even larger version, the L26 HT-4900, debuted in 1991 at 4.9 L with a square 92 mm bore and stroke. Power was the same as the 4500 at 200 hp (149 kW) but torque was up slightly to 275  ft·lbff (373 N·m).

The HT-4900 was used throughout the Cadillac line. It was phased out in favor of the newer Cadillac Northstar engine in the mid-1990s. Production ended in 1996.

Cadillac use of non-Cadillac V8s

The first Cadillac use of a non-Cadillac V8 was the 1975 Seville, which used an Oldsmobile 5.7L engine. From 1982 to 1985, all rear-wheel drive Cadillacs (except for the limousines) could be ordered with the 5.7 L Oldsmobile LF9 Diesel V8. From 1986 to 1989, the rear-wheel drive Cadillacs (the Fleetwood Brougham and Brougham) used a 5.0 L (307 in³) Oldsmobile carbureted V8 (replacing the Cadillac HT-4100). In 1990 a 175 hp, fuel-injected 5.7 L (350 in³) Chevrolet small-block V8 became optional. In 1991 the Oldsmobile 307 was replaced with a 5.0 L (305 in³) fuel-injected Chevrolet V8. In 1993 the 180 hp (134 kW) 350 in³ V8 became standard in the newly-renamed Cadillac Fleetwood. In 1994 this was replaced with a detuned Corvette LT1 V8 with 260 hp (194 kW), which the Fleetwood would use until it was discontinued at the end of the 1996 model year. The current Cadillac CTS-V uses the base Corvette's 6.0 L LS2 V-8. Earlier CTS-V's used the previous generation Z06's LS6 V-8.


Cadillac's most technologically advanced engine since the original OHV V8 bowed in 1992. This new DOHC Cadillac Northstar engine is documented elsewhere. Today, this engine is the only one at General Motors to be closely associated with a single marque. Although Oldsmobile and Pontiac have borrowed the Northstar architecture for their V8 (and even V6) engines, it was not until the 2005 Pontiac Bonneville that a non-Cadillac car used the Northstar name.

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