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Cadillac V8 engine
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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.
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.
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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.
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 of displacement. Output was .
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 .
The L-Head was on the Ward's 10 Best Engines of the 20th century list.
L-Head applications:
Cadillac created a new V8, the 341, for 1928. It was a 341 in³ engine and produced . 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 . This used a bore and stroke. This engine was used in the Series 353/355/355B/355C/355D and Series 10.
Monobloc
A "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 cylinders and crankcase were cast as a single unit , and it used hydraulic valve lifters for durability. This design allowed the creation of the mid-priced Series 60 line.
Bore was and stroke was . This engine was modified with a bore for the 1936-1948 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 in³ in Cadillac V-8 models to , while the LaSalle Straight-8 of 1934–1936 that was an Oldsmobile engine actually was replaced with the 1936 smaller version at . In 1941, the LaSalle nameplate was phased out along with the 322 in³, and Cadillacs, all 346 in³ 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 each produced a new V8 design (the Oldsmobile engine was the 303).
Both of the engines were Overhead valve designs. The Cadillac 331 engine featured a "dry" (coolant exited through an assembly attached directly to the cylinder heads), open runner (requiring the use of a tappet valley cover) intake manifold, rear-mounted distributor, and shaft-mounted rockers. An untrained eye could mistake this engine for the GEN 1 AMC V8 engine whereas the AMC counterpart uses two wing nuts per cover in its centerline, the Cadillac parts are secured through screws in its gasket perimeter. This engine also featured an oiling scheme that used a cast-in passage above and between the lifter galleries. This fed oil to the cam and crank by grooves machined into the cam bores. A single drilled passage per bearing saddle fed both cam and crank journals. This design was used in the Chevrolet Small-Block engine, GEN 1 AMC V8 engine , and the 'top oiler' Ford FE engine and the Ford MEL V8 . A design that it shares with the Oldsmobile Rocket V8 is a skirtless block where the oil pan flange does not descend appreciably below the crankshaft centerline.
365
Displacement was up to for 1956, and the 1958 Eldorado 3-2bbl version produced .
390
A longer stroke pushed displacement to for 1959, yielding , while the Eldorado six-pack reached .
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 lower, narrower, and 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 lighter than its predecessor, for a total dry weight of .
390
For 1963 the revised engine shared the same bore and stroke of its predecessor, for an unchanged displacement of . Power was unchanged at , as was torque at .
429
For 1964 the engine had a bore and a stroke, raising displacement to . Power rose to and torque to . 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, 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 bore and a stroke for a displacement of . It delivered @ 4400 rpm, and a massive torque, produced at just 3000 rpm. The new engine was about heavier than its predecessor. It was used through 1974. It was designed with potential for a 500-cubic inch displacement.
500
For 1970 Cadillac fitted a crankshaft with a stroke, increasing total displacement on the engine to . At introduction it was rated at , SAE gross, and of torque. For 1971 compression was reduced from 10:1 to 8.5:1, the lowered compression ratio dropped the 500's gross output from to , or in the new SAE net ratings. By 1976, its final year, it had fallen to . However, a new Bendix electronic fuel injection system was offered as an option, and it increased power output to .
The 500 was exclusive to the Eldorado until 1975 where the powerplant was available in all Cadillacs except for the Seville, which was powered by a fuel-injected Oldsmobile 350.
| Year | Engine Vin Code | Engine Letter Code | Cubic Inch | Rated Horsepower | Rated Torque | Bore & Stroke | Compression Ratio | Oil Pressure
PSI |
|---|
| 1968-1969 | None | None | 472 | 375 hp @ 4400 rpm | 525 lb·ft @ 3000 rpm | 4.300 X 4.060 | 10.5:1 | 33 | | 1970 | None | None | 472 | 375 hp @ 4400 rpm | 525 lb·ft @ 3000 rpm | 4.300 X 4.060 | 10.0:1 | 35-40 | | 1970 | None | None | 500 | 400 hp @ 4400 rpm | 550 lb·ft @ 3000 rpm | 4.300 X 4.304 | 10.0:1 | 35-40 | | 1971 | R | 61E,Q | 472 | 345 hp @ 4400 rpm | 500 lb·ft @ 2800 rpm | 4.300 X 4.060 | 8.5:1 | 35-40 | | 1971 | S | 61E,Q | 500 | 365 hp @ 4400 rpm | 535 lb·ft @ 2800 rpm | 4.300 X 4.304 | 8.5:1 | 35-40 | | 1972 | R | 62E,Q | 472 | 220 hp @ 4400 rpm | 365 lb·ft @ 2400 rpm | 4.300 X 4.060 | 8.5:1 | 35 | | 1972 | S | 62E,Q | 500 | 235 hp @ 4400 rpm | 385 lb·ft @ 2400 rpm | 4.300 X 4.304 | 8.5:1 | 35 | | 1973 | R | 63E,Q | 472 | 220 hp @ 4400 rpm | 365 lb·ft @ 2400 rpm | 4.300 X 4.060 | 8.5:1 | 35 | | 1973 | S | 63E,Q | 500 | 235 hp @ 4400 rpm | 385 lb·ft @ 2400 rpm | 4.300 X 4.304 | 8.5:1 | 35 | | 1974 | R | 64E,Q | 472 | 205 hp @ 4400 rpm | 365 lb·ft @ 2400 rpm | 4.300 X 4.060 | 8.5:1 | 35 | | 1974 | S | 64E,Q | 500 | 210 hp @ 3600 rpm | 380 lb·ft @ 2000 rpm | 4.300 X 4.304 | 8.5:1 | 35 | | 1975 | S | 65E,Q | 500 | 210 hp @ 3600 rpm | 380 lb·ft @ 2000 rpm | 4.300 X 4.304 | 8.5:1 | 35 | | 1976 | S | 66E,Q | 500 | 190 hp @ 3600 rpm | 360 lb·ft @ 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 Oldsmobile V8, Cadillac also began work on smaller proprietary engines.
425
In 1977 Cadillac introduced a new V8, based on the architecture of the 472, but with a smaller, bore and the same stroke. The new engine was also lighter.
The 425 was offered in L33 form, with a four-barrel carburetor, producing at 4000 rpm and of torque at 2000 rpm, and L35 with electronic port fuel injection for ; 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 472 family engine de-bored to but retaining the 472 and 425 engines' 4.06" stroke for a total displacement of . The reduction in displacement was largely an effort to meet CAFE requirements for fuel economy. Throttle-body fuel injection was now standard except for Commercial Chassis for hearse and ambulance builders.
Cadillac referred to this new TBI (throttle body injection) fuel system as Digital Fuel Injection (DFI); this particular induction system was later adopted by other GM divisions, except on Oldsmobile V8s, and was used well into the 1990s on GM trucks.
Power output dropped to at 3600 rpm and torque to at 2000 rpm in DEFI forms as used on the front wheel drive Seville and Eldorado but on the 4-barrel Quadrajet-equipped RWD models. This engine was standard on all Cadillacs except the redesigned Seville, in which it was optional.
For 1981 Cadillac introduced a new engine that would become notorious for its unreliability (the electronic systems, not the robust mechanical design), the V8-6-4 (L62). The L61 had not provided a significant improvement in the company's CAFE numbers, so Cadillac and Eaton Corporation devised a cylinder deactivation system called Modulated Displacement that would shut off two or four cylinders in low-load conditions such as highway cruising, then reactivate them when more power was needed. When deactivated, solenoids mounted to those cylinders' rocker-arm studs would disengage the fulcrums, allowing the rockers to "float" and leave the valves closed despite the continued action of the pushrods. These engines are easily identified by their rocker covers, which each have elevated sections over 2 cylinders with electrical connectors on top... With the valves closed the cylinders acted as air-springs, which both eliminated the feel of "missing" and kept the cylinders warm for instant combustion upon reactivation. Simultaneously, the engine control module would reduce the amount of fuel metered through the TBI unit. On the dashboard, an "MPG Sentinel" digital display could show the number of cylinders in operation, average or instantaneous fuel consumption (in miles per gallon) or estimated range based on the amount of fuel remaining in the tank and the average mileage since the last reset.
Another rare and advanced feature introduced with DFI was Cadillac's truly "on-board" diagnostics. For all those mechanics who had to deal with the 368's, the cars contained diagnostics that didn't require the use of any special external computer scan-tool... The new Electronic Climate Control display, along with the MPG Sentinel, provided on-board readout of any stored trouble codes, instantaneous readings from all the various engine sensors, forced cycling of the underhood solenoids and motors, and on the V8-6-4 motors, manual cylinder-pair control. The L62 produced at 3800 rpm and at 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 modern computing power (and using oil pressure to deactivate the valves by collapsing the lifters) Cadillac's 1981 V8-6-4 proved to have insurmountable teething problems, both mechanically and electronically. The biggest issue was that the engine control computer simply lacked the power to efficiently manage the number of cylinders in operation. In an effort to increase reliability, Cadillac issued 13 updated PROM chips for the engine control modules, but many of these engines simply had their Modulated Displacement function disabled by dealers, leaving them with permanent eight-cylinder operation (it actually only required disconnecting a single wire.) 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 carbureted 368 remained in the Commercial Chassis through 1984.
The 368 (essentially a reduced-bore 472 and even sharing the same timing chain) has the distinction of being the last 'big-block' traditional cast-iron pushrod V8 engine available in production cars - it lasted until 1984 in the limousines. All rival big blocks disappeared between 1976 and 1978. In the RWD models it was always coupled with the heavy duty THM400 transmission, the last factory-produced GM car to come with this.
HT-4100
A new engine was introduced for 1982, the HT-4100 (option code LT8). It was a 4100 cc V8, designed for transverse, front wheel drive applications. It was originally slated for 1983 and a new line of downsized Cadillac sedans. Delays in the downsizing program (shared with Buick and Oldsmobile) postponed the introduction of those models until 1985, and the new V8 was rushed into production for the 1982 model year.
Design Features
HT stood for High Technology. 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 used an ECM that for the first time incorporated a detailed on-board computer. Every parameter of engine performance could be displayed on the heater control while the car was being driven. The HT4100 also pioneered other design features including removable cylinder sleeves, high operating temperature for emission control (210 degrees, compared to 180 in earlier engines), free circulation of coolant between the block and the heads, and bimetal construction that mounted heat-tolerant cast-iron heads onto a weight-saving aluminum block. The engine had a bore of and stroke of , for a total displacement of . It initially was equipped with throttle-body fuel injection, with output of at 4400 rpm and of torque at 2000 rpm.
In 1982 the HT4100 was the standard engine for the front-wheel-drive Eldorado and Seville. It was also placed in many rear-wheel-drive DeVilles, and was available for the Fleetwood.
The HT4100 was prone to failure of the intake manifold gasket. It may not have been the most successful engine to sit under the hood of a Cadillac, but potential buyers were no more satisfied with the other two engines available at the time, the V8-6-4 and the Oldsmobile 5.7 L Diesel. Reliability issues soiled the reputation of the HT4100. Kits were sold to retrofit the cars with Chevrolet engines (Buick and Oldsmobile V6s would also fit, but were much harder to install). Sales remained strong, exceeding 100,000 in 1984. Cadillac's share of the luxury car market diminished rapidly after 1985.
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 valvetrain friction, in addition to multiport fuel injection. This engine was rated at at 4300 rpm and of torque at 3200 rpm. The 4.1 was superseded by larger-displacement engines, and ceased production after the 1988 model year.
4.5
Although it was an improved and enlarged version of the HT4100, the 4.5 L engine was never called HT4500 by Cadillac.
Engineering allowed the company to begin increasing displacement and output again. A bored-out (to ) 4.5 version was introduced in 1988 with and throttle body injection. Various versions of this engine were built from this introduction to the end of production in 1992 including a high-output LW2 version with multiport fuel injection which produced and for the Allante. Outside of the Allante, Cadillac introduced a port fuel injected 4.5 L V8 engine in 1990 with and across their car line up.
L26 4.9
Although an improved and enlarged version of the HT4100, it was never called HT4900 by Cadillac.
A larger version, the L26 4.9, debuted in 1991 at 4.9 L with a square bore and stroke. Despite the fact that it had similar output to Allante's 4.5 L port fuel injected V-8, the 4.9 L engine represented a significant upgrade for the remainder of the Cadillac lineup. Horsepower output was up from the previous 1990 4.5L engine and torque was up by , to and . Both the 4.9 and 4.5 port fuel injected engines required premium fuel due to a 9.5:1 compression ratio. The 4.9 produces its maximum horsepower at 4100 rpm.
The 4.9 was used throughout the Cadillac line. It was phased out in favor of the newer Cadillac Northstar engine; production ended in 1995.
Cadillac use of non-Cadillac V8s
Seville
The first Cadillac use of a non-Cadillac V8 was the 1975 Seville, which used an Oldsmobile 350 in3 engine. It featured Cadillac-exclusive Bendix electronic fuel injection (as distinct from computerized "digital" injection.) It was rated at , and the conventional Oldsmobile Rocket 350 had . Starting with the second generation Seville, Cadillac powerplants were optioned (L62 and the HT4100); from the third generation (1986), all Sevilles were Cadillac-powered.
Fleetwood (RWD)/Deville (RWD)/Brougham (RWD)
From 1982 to 1985, all rear-wheel drive Cadillacs (except for the limousines) could be ordered with the 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 1990, the rear-wheel drive Cadillac Brougham used a Oldsmobile carbureted V8 (replacing the Cadillac HT-4100).
In 1990 a , fuel-injected Chevrolet small-block V8 (RPO LO5) became optional when the towing package is selected.
In 1991 the Oldsmobile 307 was replaced with a throttle body fuel-injected Chevrolet V8 (RPO LO3 - same powerplant used in Chevrolet's Caprice and C/K light trucks).
In 1993 the V8 became standard in the newly-renamed Cadillac Fleetwood.
In 1994 this was replaced with an iron headed Chevrolet LT1 V8 with , which the Fleetwood would use until it was discontinued at the end of the 1996 model year.
With the introduction of the Escalade to the Cadillac lineup, the L31 was used, as it was part of the Chevy truck line on which the Escalade was based. In 2001, the new redesigned Escalade picked up the performance version of the 6.0 L LS series engine RPO LQ9. Currently this engine is still in use in Cadillac Escalades. All Escalades are AWD. Beginning in 2007 all Cadillac Escalades are equipped with Generation IV 6.2 L engines. This new engine option is shared with the GMC Denali.
CTS-V
The 2003 to 2005 CTS-V's used the previous generation Corvette Z06's 5.7 L LS6 V8.
The 2006 and 2007 Cadillac CTS-V uses the 6.0 L LS2 V8, similar to that used in the standard Corvette C6.
The 2009 CTS-V carries a supercharged 6.2 L LSA variant, producing at least (in preliminary ratings). This is similar to the LS9 used in the high-performance 2009 Corvette ZR1, but uses a different model of supercharger (the LS9 produces ).
Northstar
Cadillac's most technologically advanced engine since the original arrived in 1992 is the DOHC Northstar unit. Although Oldsmobile, Pontiac, and Buick have borrowed the Northstar architecture for their V8 (and even V6) engines, it was not until the 2004 Pontiac Bonneville that a non-Cadillac used the Northstar name.
The Northstar is broken up into different versions depending on model usage and model year.
4.6 L
The version was available starting in 1994 on all models
except Seville STS and Eldorado ESC and the rear-drive Fleetwood.
These models,including the Allante had versions of the Northstar.
300hp (citation needed) on 2000-2005
on 2005-present
4.4 L
The 4.4 L versions were all supercharged, exclusive to Cadillac's V-series. The present STS-V engine, since 2006, produces and under the SAE certified rating system.
The 2006 - 2008 XLR-V uses the same supercharged Northstar V8 as the STS-V, though output is down somewhat due to design changes made to accommodate the model's more limited underhood space. For the XLR-V, the SAE certified output is and . The supercharger and four intercoolers are built into the intake manifold.
The bores were reduced in size to increase block strength, increasing the safety margin under boost.
4.0 L
This is the Oldsmobile Aurora variant, never installed in a Cadillac. The Aurora's cylinder heads had lower flow characteristics to match the engine's reduced size. The 4.0 L engine produces .
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:
GM later standardized on the later generations of the Chevrolet design:
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