Editing Cadillac V8 engine (section)

==OHV==<!-- This section is linked from [[V8 engine]] -->

===331 series===
For 1949, Cadillac and [[Oldsmobile]] each produced their V8 designs (the Oldsmobile engine was the [[Oldsmobile V8 engine#303|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 engine|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 {{cvt|3+13/16|x|3+5/8|in|mm|1}} for an overall displacement of {{cvt|5425|cc|cuin L|1|order=out}}. 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 {{cvt|365|cuin|L|1}} for 1956 by increasing the bore to {{convert|4|in|mm|1}} while maintaining the {{cvt|3+5/8|in|mm|1}} 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 {{cvt|335|hp|kW|0}}.

====390====
A longer, {{cvt|3+7/8|in|mm|1}} stroke pushed displacement to {{cvt|6384|cc|cuin L|1|order=out}} for 1959, yielding {{cvt|325|hp|kW|0}}, while the Eldorado Tri-power reached {{cvt|345|hp|kW|0}}.

===390 series===
[[Image:1962 Cadillac Series 62 390 engine.jpg|right|thumb|250px|1962 [[Cadillac Series 62]] 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 rod]]s and was {{cvt|1|in|mm}} lower, {{cvt|4|in|mm|1}} narrower, and {{cvt|1.25|in|mm}} shorter. The accessories (water pump, [[power steering]] pump, [[distributor]]) mounted on a [[die casting|die-cast]] [[aluminum]] housing at the front of the engine for improved accessibility. An [[alternator]] replaced the former [[Electrical generator|generator]]. The [[crankshaft]] was cored out to make it both lighter and stronger. The revised engine was {{cvt|52|lb|kg|0}} lighter than its predecessor, for a total dry weight of {{cvt|595|lb|kg|0}}.

The revised engine shared the same {{cvt|4x3.875|in|mm}} bore and stroke of its predecessor, for an unchanged displacement of {{cvt|390|cuin|L|1}}. Power was unchanged at {{cvt|325|hp|kW|0}}, as was torque at {{cvt|430|lbft|Nm|0}}.

====429====
For 1964, the engine had a {{cvt|4.13x4|in|mm}} bore and stroke, raising displacement to {{cvt|429|cuin|L|1}}. Power rose to {{cvt|340|hp|kW|0}} and torque to {{cvt|480|lbft|Nm|0}}. 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, {{cvt|429|cuin|L|1}} represented the limit of the original architecture's expansion, and it had been surpassed by [[Chrysler Corporation|Chrysler]]'s [[Chrysler RB engine#440|440]] and [[Lincoln (automobile)|Lincoln]]'s [[Ford MEL engine#462|462]] and [[Ford 385 engine|460]]. Cadillac went bigger, with provision for even more expansion.

At introduction, the new engine had a {{cvt|4.3x4.06|in|mm|1}} bore and stroke for a displacement of {{cvt|472|cuin|L|1}}. "Extensively redesigned" to ease maintenance, it used 10% fewer parts and 25% fewer gasketed joints as before.<ref>Ludvigsen, Karl. "Cadillac: The Great American Dream Come True", in Northey, Tom, ed. ''World of Automobiles'' (London: Orbis, 1974), Vol. 3, p.297</ref> It delivered {{cvt|375|hp|kW|0}} at 4400&nbsp;rpm and a massive {{cvt|525|lbft|Nm|0}} torque at just 3000&nbsp;rpm. The new engine was about {{cvt|80|lb|kg|0}} heavier than its predecessor. It was used through 1974. It was designed with potential for a {{convert|500|cuin|L|1|adj=on}} displacement.

====500====
<!-- This section is linked from [[V8 engine]]-->
For 1970, Cadillac fitted a crankshaft with a {{cvt|4.304|in|mm}} stroke, increasing total displacement on the engine to {{cvt|500.02|cuin|L|1}}. At its introduction it was rated at {{cvt|400|hp|kW|0}}, [[Horsepower#SAE gross power|SAE gross]], and {{cvt|550|lbft|Nm|0}} 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 {{cvt|400|bhp|kW|0}} to {{cvt|365|bhp|kW|0}}, or {{cvt|235|hp|kW|0}} in the new [[Horsepower#SAE net power|SAE net]] ratings. By 1976, its final year, it had fallen to {{cvt|190|hp|kW|0}}. However, a new [[Bendix Corporation|Bendix]] [[electronic fuel injection]] system was offered as an option, and it increased power output to {{cvt|215|hp|kW|0}}. The 500 was exclusive to the [[Cadillac Eldorado|Eldorado]] until 1975 where the powerplant was standard in all Cadillacs except for the Seville, which was powered by a fuel-injected [[Oldsmobile V8 engine#350|Oldsmobile 350]].

{| class="wikitable"
|-
!Year
! Engine [[VIN]] code
! Engine letter code
! Displacement
! Rated horsepower
! Rated torque
! Bore x stroke
! Compression ratio
! Oil pressure
|-
|1968–1969||rowspan=3|None||rowspan=3|None||rowspan=2|{{cvt|472|cuin|L|1}}|| rowspan=2|{{cvt|375|hp|kW|0}}<br />at 4400&nbsp;rpm|| rowspan=2|{{cvt|525|lbft|Nm|0}} at 3000&nbsp;rpm||rowspan=2|{{cvt|4.3x4.06|in|mm|1}}||10.5:1||{{cvt|33|psi|bar}}
|-
|rowspan=2|1970
(SAE gross)
| rowspan="2" |10.0:1||rowspan=4|{{cvt|35-40|psi|bar}}
|-
|{{cvt|500|cuin|L|1}}|| {{cvt|400|hp|kW|0}}<br />at 4400&nbsp;rpm|| {{cvt|550|lbft|Nm|0|}} at 3000&nbsp;rpm||{{cvt|4.3x4.304|in|mm|1}}
|-
|rowspan=2|1971
(SAE gross)
|R||rowspan=2|61E,Q||{{cvt|472|cuin|L|1}}|| {{cvt|345|hp|kW|0}}<br />at 4400&nbsp;rpm|| {{cvt|500|lbft|Nm|0}} at 2800&nbsp;rpm||{{cvt|4.3x4.06|in|mm|1}}||rowspan=10|8.5:1
|-
|S||{{cvt|500|cuin|L|1}}|| {{cvt|365|hp|kW|0}}<br />at 4400&nbsp;rpm|| {{cvt|535|lbft|Nm|0}} at 2800&nbsp;rpm||{{cvt|4.3x4.304|in|mm|1}}
|-
|rowspan=2|1972
(SAE net)
|R||rowspan=2|62E,Q||{{cvt|472|cuin|L|1}}|| {{cvt|220|hp|kW|0}}<br />at 4400&nbsp;rpm|| {{cvt|365|lbft|Nm|0}} at 2400&nbsp;rpm||{{cvt|4.3x4.06|in|mm|1}}||rowspan=8|{{cvt|35|psi|bar}}
|-
|S||{{cvt|500|cuin|L|1}}|| {{cvt|235|hp|kW|0}}<br />at 4400&nbsp;rpm|| {{cvt|385|lbft|Nm|0}} at 2400&nbsp;rpm||{{cvt|4.3x4.304|in|mm|1}}
|-
|rowspan=2|1973||R||rowspan=2|63E,Q||{{cvt|472|cuin|L|1}}|| {{cvt|220|hp|kW|0}}<br />at 4400&nbsp;rpm|| {{cvt|365|lbft|Nm|0}} at 2400&nbsp;rpm||{{cvt|4.3x4.06|in|mm|1}}
|-
|S||{{cvt|500|cuin|L|1}}|| {{cvt|235|hp|kW|0}}<br />at 4400&nbsp;rpm|| {{cvt|385|lbft|Nm|0}} at 2400&nbsp;rpm||{{cvt|4.3x4.304|in|mm|1}}
|-
|rowspan=2|1974||R||rowspan=2|64E,Q||{{cvt|472|cuin|L|1}}|| {{cvt|205|hp|kW|0}}<br />at 4400&nbsp;rpm|| {{cvt|380|lbft|Nm|0}} at 2400&nbsp;rpm||{{cvt|4.3x4.06|in|mm|1}}
|-
|rowspan=3|S||rowspan=3|{{cvt|500|cuin|L|1}}|| rowspan=2|{{cvt|210|hp|kW|0}}<br />at 3600&nbsp;rpm|| rowspan=2|{{cvt|380|lbft|Nm|0}} at 2000&nbsp;rpm||rowspan=3|{{cvt|4.3x4.304|in|mm|1}}
|-
|1975||65E,Q
|-
|1976||66E,Q|| {{cvt|190|hp|kW|0}}<br />at 3600&nbsp;rpm|| {{cvt|360|lbft|Nm|0}} at 2000&nbsp;rpm
|}

===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 {{cvt|350|cuin|L|1}} Oldsmobile V8, Cadillac also began work on its own proprietary engines.<ref>{{cite web |author1=John Gunnell |title=Vintage V8s: Exploring 100 Years of Cadillac Engines |url=http://www.enginebuildermag.com/2014/03/vintage-v8s-exploring-100-years-eight-cylinder-cadillac-engines/ |website=Engine Builder |access-date=July 17, 2021 |date=March 10, 2014}}</ref><ref>{{cite web |author1=Don Sherman |title=Century Club: The 100-Year History of Cadillac V-8s |url=http://blog.caranddriver.com/century-club-the-100-year-history-of-cadillac-v-8s/ |website=Car and Driver |access-date=July 17, 2021 |archive-url=https://web.archive.org/web/20140727032128/http://blog.caranddriver.com/century-club-the-100-year-history-of-cadillac-v-8s/ |archive-date=July 27, 2014 |date=July 25, 2014}}</ref>

In 1977, Cadillac introduced a new {{cvt|425|cuin|L|1}} V8, based on the architecture of the 472, but with a smaller, {{cvt|4.082|in|mm}} bore and the same {{cvt|4.06|in|mm|1}} stroke. The new engine was also {{cvt|100|lb|kg|0}} lighter.

The 425 was offered in '''L33''' form, with a four-barrel carburetor, producing {{cvt|180|hp|kW|0}} at 4000&nbsp;rpm and {{cvt|320|lbft|Nm|0}} of torque at 2000&nbsp;rpm, and '''L35''' with electronic [[multi-port fuel injection]] for {{cvt|195|hp|kW|0}} and {{cvt|320|lbft|Nm|0}} of torque, but peaked at 2400&nbsp;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 {{cvt|3.8|in|mm}} but retaining the 472 and 425 engines' {{cvt|4.06|in|mm|1}} stroke for a total displacement of {{cvt|368|cuin|L|1}}. The reduction in displacement was largely an effort to meet [[Corporate Average Fuel Economy|CAFE]] requirements for [[Fuel economy in automobiles|fuel economy]]. [[Throttle-body fuel injection]] was now standard on Eldorado and Seville when equipped with the 368. [[Rear-wheel drive|Rear-wheel-drive]] cars and the Commercial Chassis for hearse and ambulance builders used the [[Rochester Products Division|Rochester]] [[Quadrajet]] 4-barrel [[carburetor]].

Cadillac referred to this new TBI (throttle-body fuel injection) system as [[Digital fuel injection|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 {{cvt|145|hp|kW|0}} at 3600&nbsp;rpm and torque to {{cvt|270|lbft|Nm|0}} at 2000&nbsp;rpm in DEFI forms as used on the [[front-wheel drive|front-wheel-drive]] Seville and Eldorado but {{cvt|150|hp|0}} on the four-barrel Quadrajet-equipped RWD models. This engine was standard on all Cadillacs except the redesigned [[Cadillac Seville|Seville]], in which it was optional.

====V8-6-4====
{{anchor |V8-6-4|L62}}
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 [[displacement on demand|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, [[solenoid]]s mounted to those cylinders' [[rocker arm]] studs would disengage the [[Lever|fulcrum]]s, allowing the rockers to "float" and leave the valves closed despite the continued action of the [[pushrod]]s. These engines are easily identified by their [[rocker cover]]s, 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 automobiles|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.<ref>Sessler, Peter C., [https://books.google.com/books?id=eT7LT69STO0C&pg=PA23 ''Ultimate American V-8 Engine Data Book'']. MBI Publishing Company, 2010, p. 23. {{ISBN|978-0-7603-3681-6}}</ref>

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 tool|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 {{cvt|140|hp|kW|0}} at 3800&nbsp;rpm and {{cvt|265|lbft|Nm|0}} at 1400&nbsp;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 [[Exhaust gas recirculation|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 [[Programmable ROM|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''.