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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.

Contents

L-Head

Monobloc

LaSalle

OHV

331

365

390

Redesigned OHV

390

429

World's largest

472

500

Downsized OHV

425

368 and V8-6-4

Aluminum OHV

HT-4100

4.5 (although an improved version and enlarged version of the HT4100, it was never called HT4500 by Cadillac)

4.9 (although an improved and enlarged version of the HT4100, it was never called HT4900 by Cadillac)

Cadillac use of non-Cadillac V8s

Northstar

See also

External Links

L-Head

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.

Monobloc

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.

LaSalle

In 1937, the new Monobloc Flathead gained 24 cubic inches in Cadillac V-8 models to 346 in³, while the LaSalle Straight-8 of 1934–1936 was replaced with the 1936 smaller 322 in³ version at 125 hp (93 kW). In 1941, the LaSalle nameplate was phased out along with the 322 in³, and Cadillacs, all 346cid powered, were available with the new Hydramatic automatic transmission which debuted in Oldsmobile the previous year. These engines were produced through 1948.

OHV

331

For 1949, Cadillac and Oldsmobile shared a new V8 design, Olds at 303 in³ engine and Cadillac at 331 in³. Though they were not physically related, many lessons learned by one division were incorporated into the other's design, and the result were two engines known for their excellent power-to-weight ratio, fuel economy, and smooth running. These were the first OHV V8's that were widely, commercially available in a US automobile since Chevrolet's attempt in 1917. Output was impressive at 160 hp (119 kW), a 25hp boost over the outgoing 346. 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).

365

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

390

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 mm) lower, 4 inches (102 mm) narrower, and 1¼ in (32 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 (24 kg) lighter than its predecessor, for a total dry weight of 595 lb (270 kg).

390

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 kW), as was torque at 430 ft·lbf (583 N·m).

429

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 (254 kW) and torque to 480 ft·lbf (650 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.

472

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·lbf (712 N·m) torque, produced at just 3000 rpm. The new engine was about 80 lb (36 kg) heavier than its predecessor. It was used through 1974.

500

For 1970 Cadillac stroked the V8 to 4.304 in (109.3 mm), increasing total displacement on the engine up to a full 500 in³ (8.2 L). At introduction it was rated at 400 horsepower (298 kW), SAE gross, and 550 ft•lbf (750 N•m) of torque. For 1971 compression was reduced from 10:1 to 8.5:1, the lowered compression ratio dropped the 500-cubic-incher's output from 400 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 (142 kW). However, a new Bendix electronic fuel injection system was offered as an option, and it pumped up output to 215 horsepower. In 1972, Cadillac changed the horsepower rating from gross--measured at the flywheel with open exhaust and no accessories--to net--measured at the flywheel with full accessories and restrictive exhaust--which would account for the horsepower drop in the chart. Despite the large differences in horsepower ratings, all years from 71-76 made roughly the same power.
'General Engine Specifications Chart'

Year	Engine Vin Code	Engine Letter Code	Cubic Inch	Rated Horsepower	Rated Torque	Bore & Stroke	Compression Ratio	Oil PressurePSI
1968-1969	None	None	472	375 hp @ 4400 rpm	525 ft•lbf @ 3000 rpm	4.300 X 4.060	10.5:1	33
1970	None	None	472	375 hp @ 4400 rpm	525 ft•lbf @ 3000 rpm	4.300 X 4.060	10.0:1	35-40
1970	None	None	500	400 hp @ 4400 rpm	550 ft•lbf @ 3000 rpm	4.300 X 4.304	10.0:1	35-40
1971	R	61E,Q	472	345 hp @ 4400 rpm	500 ft•lbf @ 2800 rpm	4.300 X 4.060	8.5:1	35-40
1971	S	61E,Q	500	365 hp @ 4400 rpm	535 ft•lbf @ 2800 rpm	4.300 X 4.304	8.5:1	35-40
1972	R	62E,Q	472	220 hp @ 4400 rpm	365 ft•lbf @ 2400 rpm	4.300 X 4.060	8.5:1	35
1972	S	62E,Q	500	235 hp @ 4400 rpm	385 ft•lbf @ 2400 rpm	4.300 X 4.304	8.5:1	35
1973	R	63E,Q	472	220 hp @ 4400 rpm	365 ft•lbf @ 2400 rpm	4.300 X 4.060	8.5:1	35
1973	S	63E,Q	500	235 hp @ 4400 rpm	385 ft•lbf @ 2400 rpm	4.300 X 4.304	8.5:1	35
1974	R	64E,Q	472	205 hp @ 4400 rpm	365 ft•lbf @ 2400 rpm	4.300 X 4.060	8.5:1	35
1974	S	64E,Q	500	210 hp @ 3600 rpm	380 ft•lbf @ 2000 rpm	4.300 X 4.304	8.5:1	35
1975	S	65E,Q	500	210 hp @ 3600 rpm	380 ft•lbf @ 2000 rpm	4.300 X 4.060	8.5:1	35
1976	S	66E,Q	500	190 hp @ 3600 rpm	360 ft•lbf @ 2000 rpm	4.300 X 4.304	8.5:1	35

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.

425

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 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 (434 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 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 (366 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 kW) @ 3800 rpm and 265 ft·lbf (359 N·m) @ 1400 rpm. Cadillac hailed the L62 as a technological masterpiece, and made it standard equipment across the whole Cadillac line.
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

HT-4100

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. The ''HT'' stood for High Technology, and for its time, the engine and its electronic control module (ECM) were quite sophisticated. Despite having a throttle body injection system (as opposed to port fuel injection), the HT4100 engine used an ECM that--for the first time--incorporated a detailed on board computer. Beginning in 1985, this on board computer could be used to read parameters of every engine and control sensor on the vehicle. This feature makes Cadillacs equipped with this engine excellent buys for the home, shadetree mechanic.
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 (258 N·m)of torque at 2000 rpm. Since most Cadillacs still had curb weights in excess of 4,000 lb (1,800 kg), acceleration was lackluster.
All HT-4100 engines had significant reliability problems, specifically rapid main bearing and camshaft lubrication (wear) failures; however, those of the first year or two (1982 and 1983)were somewhat more troublesome than the 1984-1987 engines as engineering improvements were made each year of HT4100 production. Both of the these problems were caused by engine coolant entering the engine's crankcase from the intake manifold gaskets at the heads. Once the coolant mixed with the engine oil, the lubrication properties dropped significantly.
Intake manifold coolant leaks were common on early HT-4100 engines with as little as 30,000 miles. The "design" solution used by Cadillac was to replace the intake manifold bolts with a bolt with a smaller diameter shank in conjunction with a Bellville (spring) washer. However, once coolant leaks were discovered, the intake manifold had to be removed to replace the gaskets and also to use the GM fix (bolt/washer kit). After two years of production, Cadillac began installing and recommending the field installation of GM Coolant Supplement which was basically a "stop leak" type of product to try to seal the engine at its gasket to prevent oil and coolant from mixing. This product came as tablets which were crushed and added to the coolant. It was only partially successfull in preventing oil/water problems and could actually clog the cooling system if too much was instilled. The vast majority of HT4100's did not make 60,000 miles without severe bearing knock or complete engine failure and complete engine failure was known to occur in as few as 30,000 miles. Cadillac replaced hundreds of thousands of these engines under warranty; so many, in fact, that it was common to see bad HT4100's stacked like cordwood in service departments across North America. Also, in engines with no discernable problems, one overheating episode often would destroy the engine as it was nowhere near as forgiving of high temperatures as a cast iron engine.
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 (127 kW) @ 4300 rpm and 235  ft·lbf (319 N·m) of torque @ 3200 rpm. The 4.1 was superseded by larger-displacement engines, and ceased production after the 1988 model year.

4.5 (although an improved version and enlarged version of the HT4100, it was never called HT4500 by Cadillac)

Engineering allowed the company to begin to raise displacement and output again. A bored-out (to 92 mm) 4.5 L (273 in³) '4.5' version was introduced in 1988 with 155 hp (116 kW) and throttle body injeciton. 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·lbf (366 N·m). Outside of the Allante, Cadillac introduced a port fuel injected 4.5L V-8 engine in 1990 with 180hp across their car line up.
The 4.5L V-8 experienced considerably less reliability issues than the 4.1L engine, with the head and intake gasket issues largely resolved.

4.9 (although an improved and enlarged version of the HT4100, it was never called HT4900 by Cadillac)

An even larger version, the 'L26 4.9', debuted in 1991 at 4.9 L (300 in³) with a square 92 mm bore and stroke. Despite the fact that it had similar output to Allante's 4.5L port fuel injected V-8, the 4.9L engine represented a significant upgrade for the remainder of the Cadillac lineup. Horsepower output was up 20 hp from the previous 1990 4.5L engine and torque was up by 30 lb-ft. Both the 4.9 and 4.5 port fuel injected engines required premium fuel.
Despite its rather low horsepower output, owners of 4.9L engines are often surprised by the engine's power, due to its wide powerband, and plethora of low end torque. Indeed, a 4.9L engine produces its maximum horsepower by only 4100 rpms, so off-the-line response is extremely strong. Its best performance is in the 0-45 MPH range (first gear).
The 4.9 was used throughout the Cadillac line. It was phased out in favor of the newer Cadillac Northstar engine; production ended in 1996.

Cadillac use of non-Cadillac V8s

The first Cadillac use of a non-Cadillac V8 was the 1976 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. In fact, for most of its life, the 1980-1985 version of Cadillac's Seville came standard with Oldsmobile's V8 diesel, with the gas engine being a no-cost option. From 1986 to 1989, the rear-wheel drive Cadillac 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.

Northstar

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, Pontiac, and Buick 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.

See also

From the 1950s through the 1970s, each GM division had its own V8 engine family. Some were shared among other divisions, but each respective design was engineered and developed by its own division:

★ Buick V8 engine

★ Chevrolet Small-Block engine

★ Chevrolet Big-Block engine

★ Oldsmobile V8 engine

★ Pontiac V8 engine
GM later standardized on the later generations of the Chevrolet design:

★ GM LT engine — Generation II small-block

★ GM LS engine — Generation III/IV small-block

★ List of GM engines

External Links

★ The Caddy Engine Guide

★ Maximum Torque Specialties - Cadillac Forum

★ Cadillac Power - Cadillac Forum; dedicated primarily to 472/500, but also 368/425 Cadillac engines.

★ Cadillac Owners - Cadillac Forum