A "
monobloc engine" was used in the 1936
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 and stroke was . This engine was closely related to a monobloc design earlier introduced in the 1936–1948 engine, which was modified with a bore. This was used in the
Series 60/60S/61/62/63/65/67 and
70/72/75. It was also used in a dual setup in
tanks (e.g.
M5 Stuart and the
M24 Chaffee), in
World War II mated to a
Hydramatic transmission.
LaSalle V8 engine detail In 1937, the new
monobloc flathead gained in Cadillac V-8 models to , while the
LaSalle straight-8 of 1934–1936 that originated from
Oldsmobile actually was replaced with the 1936 smaller version at . In 1941, the LaSalle nameplate was phased out along with the , and Cadillacs, all powered, were available with the new
Hydramatic automatic transmission which debuted in Oldsmobile the previous year. These engines were produced through 1948. ==OHV==
331 series For 1949, Cadillac and
Oldsmobile each produced their V8 designs (the Oldsmobile engine was the
303). Both of the engines were
overhead valve designs, pioneered by Buick. 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 valve cover)
intake manifold, rear-mounted
distributor, and shaft-mounted rockers. Crankshaft end play is carried by the rear bearing on the two GM engines. It has the lighter "skirtless" block where the oil pan flange does not descend appreciably below the crankshaft centerline and they both have a partial integral cast iron clutch housing that compares to the early
Chrysler Hemi V8 design. 1955 331 engines went to a lighter "flat back" that bolted to a clutch and flywheel housing at the front of the transmission. Bore and stroke are for an overall displacement of . This engine features an oiling system which uses a central cast-in passage between the lifter galleries feeding oil to the cam and crank by grooves machined into the cam bores. A single drilled passage per bearing saddle feeds both cam and crank journals. Shared with the Oldsmobile Rocket V8 is how the lifters are supplied oil through small "bleeds" instead of placing the lifters directly into the right and left side oil supply galleries. Many early racers would replace the Cadillac hydraulic lifter and rocker assemblies with the solid lifters and adjustable rockers from the Studebaker V8 for operation at higher engine speeds.
365 Displacement was increased to for 1956 by increasing the bore to while maintaining the stroke. For the three years that the 365 was made, the base versions had a single four-barrel carburetor. The 1956 version produced 285 horsepower. The 1957 version raised that base engine output to 300 horsepower, while the 1958 base version cranked out 310. Eldorados featured multi-carb engines in all 3 years. The Eldorado engines were also optional on all other Cadillacs. The 1958 Eldorado 3-2bbl version produced .
390 A longer, stroke pushed displacement to for 1959, yielding , while the Eldorado Tri-power reached .
390 series 390 V8 engine For the 1963 model year, Cadillac redesigned its 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 . 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 stroke, raising displacement to . Power rose to and torque to . It also included its first
emission control system, which was a
positive crankcase ventilation unit. The 429 was used through the 1967 model year.
472 series Cadillac introduced an all-new engine for 1968. Although the modernized 390 series 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 and
460. Cadillac went bigger, with provision for even more expansion. At introduction, the new engine had a bore and stroke for a displacement of . "Extensively redesigned" to ease maintenance, it used 10% fewer parts and 25% fewer gasketed joints as before. It delivered at 4400 rpm and a massive torque 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 displacement.
500 For 1970, Cadillac fitted a crankshaft with a stroke, increasing total displacement on the engine to . At its introduction it was rated at ,
SAE gross, and of torque. For 1971, compression was reduced from 10.0:1 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. } at 3000 rpm|| (SAE gross) (SAE net)
425 series Starting in the mid to late 1970s, Cadillac expanded its product range, offering more mid-sized vehicles. For example, while the
Cadillac Seville initially used a variant of the Oldsmobile gasoline V8, Cadillac also began work on its own proprietary engines. 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
multi-port fuel injection for and of torque, but peaked at 2400 rpm. The 425 was used through 1979 on all Cadillacs except the Seville and 1979 Eldorados.
368 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' 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 on Eldorado and Seville when equipped with the 368.
Rear-wheel-drive cars and the Commercial Chassis for hearse and ambulance builders used the
Rochester Quadrajet 4-barrel
carburetor. Cadillac referred to this new TBI (throttle-body fuel injection) 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 mid-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 four-barrel Quadrajet-equipped RWD models. This engine was standard on all Cadillacs except the redesigned
Seville, in which it was optional.
V8-6-4 For 1981, Cadillac introduced a new engine that would become notorious for its unreliable electronics, 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 two 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 current
fuel consumption (in miles per gallon), or estimated range based on the amount of fuel remaining in the tank and the average efficiency since the last reset. Another rare and advanced feature introduced with DFI was Cadillac's truly "on-board" diagnostics. For mechanics who had to deal with the 368s, the cars contained diagnostics that did not require the use of special external computer
scan tools. 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 engines, 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 engineering problems. The main issue was that the
engine control module simply lacked the robustness, programming and processing speed to efficiently manage the cylinder-deactivation under all load conditions. In the era before electronically operated
EGR valves, the engineers also made an error in using a back-pressure-type EGR valve. While this early effort to match the vacuum-controlled EGR volume more accurately to the engine's load made sense in a conventional engine, it had the effect of causing pinging (detonation) problems in the V8-6-4 engine, because four cylinders operating under higher load needed more EGR, while they were actually producing less exhaust flow and therefore less back-pressure to operate the valve. In an effort to increase reliability, Cadillac issued thirteen updated
PROM chips for the ECMs, but many of these engines simply had their Modulated Displacement function disabled by dealers, leaving them with permanent eight-cylinder operation. This was accomplished by merely disconnecting a single wire from the transmission's "3rd-gear switch", or running it through a switch inside the car for manual override. The 368 was dropped from 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 has the distinction of being the last traditional "big-block" cast-iron pushrod V8 engine available in a production car. It lasted through 1984 in the limousines. Rival big blocks, ranging in displacement from 396 to 460 cubic inches, disappeared between 1976 and 1978. RWD models were coupled with the heavy-duty THM400 transmission, the last factory-produced GM passenger car fitted with this transmission. GM reintroduced an updated fuel management system in 2005, marketed as
Active Fuel Management or
Displacement on Demand. ==Cadillac High Technology engine==