From Wikipedia, the free encyclopedia - View original article
The Oldsmobile Rocket V8 was the first post-war OHV V8 at General Motors. Production started in 1949, with a new generation introduced in 1964. Like Pontiac, Olds continued building its own V8 engine family for decades, finally adopting the corporate Chevrolet 350 small-block and Cadillac Northstar engine only in the 1990s. All Oldsmobile V8s were manufactured at plants in Lansing, Michigan.
All Oldsmobile V8s use a 90° bank angle, and most share a common stroke dimension: 3.4375 in (87.31 mm) for early Rockets, 3.6875 in (93.66 mm) for later Generation 1 engines, and 3.385 in (86.0 mm) for Generation 2. The 260 cu in (4.3 l), 307 cu in (5.0 l), 330 cu in (5.4 l), 350 cu in (5.7 l) and 403 cu in (6.6 l) engines are commonly called small-blocks. 400 cu in (6.6 l), 425 cu in (7.0 l), and 455 cu in (7.5 l) V8s have a higher deck height (10.625 in (27.0 cm) versus 9.33 in (23.7 cm)) to accommodate a 4.25 in (108 mm) stroke crank to increase displacement. These taller-deck models are commonly called "big-blocks", and are 1 in (2.5 cm) taller and 1.5 in (3.8 cm) wider than their "small-block" counterparts.
The Rocket V8 was the subject of many first and lasts in the automotive industry. It was the first mass-produced OHV V8 in 1949; and was the last carbureted V8 passenger car engine in 1990.
As is the case with all pre-1972 American passenger car engines, published horsepower and torque figures for those years were SAE "Gross," as opposed to 1972 and later SAE Net ratings (which are indicative of what actual production engines produce in their "as installed" state - with all engine accessories, full air cleaner assembly, and full factory exhaust system in-place).
The first generation of Oldsmobile V8s ranges from 1949-1964. Each engine in this generation is quite similar with the same size block and heads.
The 303-cubic-inch (5.0 L) engine had hydraulic lifters, an oversquare bore:stroke ratio, a counterweighted forged crankshaft, aluminum pistons, floating wristpins, and a dual-plane intake manifold. The 303 was produced from 1949-1953. Bore was 3.75 in (95 mm) and stroke was 3.4375 in (87.31 mm). Cadillac used a distantly related engine which appeared in three different sizes through to the 1962 model year; though the Oldsmobile and Cadillac motors were not physically related, many lessons learned by one division were incorporated into the others design, and the result were two engines known for their excellent power-to-weight ratio, fuel economy, and smooth, strong, reliable running.
The original Oldsmobile V8 was originally to be advertised as "Kettering Power" after chief engineer Charles Kettering, but company policy disallowed the use of his name. So the engine was sold as the Oldsmobile Rocket. The engine was available in Oldsmobile's 88, Super 88, and 98 models. The 88 models acquired the nickname Rocket 88.
The 303 was available from 1949 through 1953. 1949 through 1951 "88" 303's came with a 2-barrel carburetor for 135 hp (101 kW) and 253 lb·ft (343 N·m). 1952 88 and Super 88 V8s used a 4-barrel carburetor for 160 hp (120 kW) and 265 lb·ft (359 N·m), while 1953 versions upped the compression from 7.5:1 to 8.0:1 for 165 hp (123 kW) and 275 lb·ft (373 N·m). For comparison, a 1949 Ford Flathead V8 produced just 100 hp (75 kW).
The 324-cubic-inch (5.3 L) version was also produced from 1954 until 1956. Bore was increased to 3.875 in (98.4 mm) (same as the later 283 Chevy) and stroke remained the same at 3.4375 in (87.31 mm). All high performance 324s came with 4-barrel carburetors. The 324 was shared with GMC trucks.
The 1954 88 and Super 88 V8s used an 8.25:1 compression ratio for 170 and 185 hp (126 and 137 kW) and 295 and 300 ft·lbf (399 and 406 N·m) respectively.
The 1955 upped the compression to 8.5:1 for 185 hp (138 kW) and 320 lb·ft (430 N·m) in the 88 and 202 hp (151 kW) and 332 lb·ft (450 N·m) in the Super 88 and 98. For engines built during the first part of 1955, the 324 skirted pistons had a reputation for failing due to the cast aluminum skirt separating from its steel interior brace. This problem did not appear until the engine had over 50,000 miles (80,000 km) on it. By late 1956, many Olds dealers learned about the problem.
Compression was up again in 1956 for 230 hp (170 kW) and 340 lb·ft (460 N·m) in the 88 and 240 hp (180 kW) and 350 lb·ft (470 N·m) in the Super 88 and 98.
A special 370-cubic-inch (6.1 L) variant called the 370 was used in GMC trucks alone, not shared.
Making its debut in 1957 as standard equipment on all Olds models, the 371 was produced through 1960. Bore was now 4.0 in (100 mm) (same as the 327 and 350 Chevys) and stroke was increased to 3.6875 in (93.66 mm) for 371 cu in (6.1 L). 1959 and 1960 371s used green painted valve covers. 4-barrel models used 9.25:1 compression in 1957 and 10:1 in 1958 for 277 hp (207 kW) and 400 lb·ft (540 N·m) and 305 hp (227 kW) and 410 lb·ft (560 N·m) respectively. A 1958 2-barrel version was still impressive at 265 hp (198 kW) and 390 lb·ft (530 N·m), but had problems with early camshaft failures due to the high preload valve spring forces. Then, power nosed downward for the 1959 and 1960 88 model: 270 hp (200 kW) and 390 lb·ft (530 N·m) for 1959 and 240 hp (180 kW) and 375 lb·ft (508 N·m) for 1960. It was no longer available in cars in 1961.
The 371 was also used in GMC trucks and called a '370'.
Introduced in the middle of the 1957 model year, the 1957 and 1958 J-2 Golden Rocket had three two-barrel (twin choke) carburetors with a vacuum-operated linkage. Only the center carburetor was mechanically connected to the throttle pedal, and it was the only one equipped with a choke. When the center carburetor was opened to 60° or more engine vacuum drawn from the windshield wiper pump would simultaneously open the front and rear carburetors. These carburetors did not open progressively; they were either open or closed. The J-2 engine also had a slightly thinner head gasket, raising compression to 10.0:1. It was advertised with gross power and torque ratings of 312 hp (233 kW) at 4600 rpm and 415 lb·ft (563 N·m) at 2800 rpm. Oldsmobile charged $83 for the J-2 option with the three-speed manual (or in the 98), $314 dollars with the automatic.
In practice, owners who did not regularly drive hard enough to engage the front and rear carburetors experienced problems with the linkage and carburetor throats becoming clogged, and some J-2-equipped cars had the front and rear carburetors removed and blocked off. Moreover, correct tuning was a continual headache. The package was expensive to produce, and Oldsmobile discontinued it after 1958.
Bore was up to 4.125 in (104.8 mm) for the largest first-generation Rocket, the 394 cu in (6.5 L). 394s were produced from 1959–1964 and were available on many Olds models. Most 394s used 2-barrel carburetors. Power was up to 315 hp (235 kW), even though compression was down a quarter point, to 9.75:1.
The 394 replaced the 371 in Super 88 and 98 cars for 1959 and 1960 and a detuned version was used in the 88 for 1961 and the Dynamic 88 for 1962-1964.
The 1961 through 1963 Sky Rocket (and 1964 Rocket) was a 394 cu in (6.5 L) engine. The 10:1 compression 1961 model produced 325 hp (242 kW) and 435 lb·ft (590 N·m), while the 10.25:1 1962-1964 version upped power to 330 hp (250 kW) and 440 lb·ft (600 N·m). A special 1963 10.5:1 version was also produced with 345 hp (257 kW).
From 1961-1963, Oldsmobile manufactured its own version of the Buick-designed, all-aluminum 215 engine for the F-85 compact. Known variously as the Rockette, Cutlass, and Turbo-Rocket by Oldsmobile (and as Fireball and Skylark by Buick), it was a compact, lightweight engine measuring 28 in (71 cm) long, 26 in (66 cm) wide, and 27 in (69 cm) high (same as the small-block Chevy), with a dry weight of only 320 lb (150 kg). The Oldsmobile engine was very similar to the Buick engine, but not identical: it had larger wedge(rather than hemispherical)-shaped combustion chambers with flat-topped (rather than domed) pistons, six bolts rather than five per cylinder, and slightly larger intake valves; the valves were actuated by shaft-mounted rocker arms like the Buick and Pontiac versions, but the shafts and rockers were unique to Oldsmobile. With an 8.75:1 compression ratio and a 2-barrel carburetor, the Olds 215 had the same rated hp, 155 hp (116 kW) at 4800 rpm, as the Buick 215, with 220 ft·lbf (300 N·m) of torque at 2400 rpm. With a 4-barrel carburetor and 10.25:1 compression, the Olds 215 made 185 hp (138 kW) at 4800 rpm and 230 lb·ft (310 N·m) at 3200 rpm with a manual transmission. With a 4-barrel carburetor and 10.75:1 compression, the Olds 215 made 195 hp (145 kW) at 4800 rpm and 235 lb·ft (319 N·m) at 3200 rpm with an automatic. The Buick version was rated at 200 hp with an 11:1 compression ratio.
The basic Buick/Olds 215 V8 went on to become the well known Rover V8, which still remains in limited production. The Range Rover V8 utilized the Buick-style pistons, heads, and valve train gear.
The Oldsmobile engine block formed the basis of the Repco 3-liter engine used by Brabham to win the 1966 and 1967 Formula One world championships. The early Repco engines produced up to 300 bhp (220 kW), and featured new SOHC cylinder heads and iron cylinder liners. The 1967 and later versions of the Repco engine had proprietary engine blocks.
In the mid-1980s, hot rodders discovered the 215 could be stretched to as much as 305 cu in (5 l), using the Buick 300 crankshaft, new cylinder sleeves, and an assortment of non-GM parts. It could also be fitted with high-compression cylinder heads from the Morgan +8. Using the 5 liter Rover block and crankshaft, a maximum displacement of 317.8 cu in (5,208 cc) is theoretically possible.
In 1962 and 1963 Oldsmobile built a turbocharged version of the 215. The small-diameter Garrett T5 turbocharger with integral wastegate was manufactured by Garrett AiResearch and produced a maximum of 5 psi (34 kPa) boost at 2200 rpm. The engine had 10.25:1 compression and a single-barrel carburetor. It was rated at 215 hp (160 kW) at 4600 rpm and 300 lb·ft (410 N·m) at 3200 rpm. In development, the high compression ratio created a serious problem with spark knock on hard throttle applications, which led Olds to use a novel water-injection system that sprayed metered amounts of distilled water and methyl alcohol (dubbed "Turbo-Rocket Fluid") into the intake manifold air-stream to cool the intake charge. If the fluid reservoir was empty, a complex double-float and valve assembly in the Turbo-Rocket Fluid path would set a second butterfly (positioned between the throttle butterfly and the turbocharger) into the closed position, limiting the amount of boost pressure. Unfortunately, many customers did not keep the reservoir filled, or had mechanical problems with the turbocharger system which resulted in many of the turbo-charger installations being removed and a conventional 4 barrel carburetor and manifold installed in its place.
The turbocharger was offered only in a special Jetfire model, which was the second turbocharged passenger car offered for public sale. The Chevrolet Corvair Spyder Turbo also manufactured by GM was ahead the Oldsmobile Jetfire Turbo by only a few weeks. Only 9,607 were sold in two model years, and many were converted by dealers to conventional four-barrel carbureted form.
The second generation of Oldsmobile V8s was produced from 1964-1990. Most of these engines were very similar, using the same bore centers, although "big-block" versions were produced with a 10.625 in (269.9 mm) deck height rather than 9.33 in (237 mm). Big-block and Diesel versions also used a larger 3.0 in (76 mm) instead of 2.5 in (64 mm) main bearing journal for increased strength. All generation-2 small-block Olds V8s used a stroke of 3.385 in (86.0 mm). The big-block engines initially used a forged crankshaft with a stroke of 3.975" for the 1965-1967 425 and 400 CID versions; starting in 1968, both the 400 cu in (6.6 L) and the 455 cu in (7.5 L) big blocks used a stroke of 4.25 in (108 mm), with crankshaft material changed to cast iron except in a few rare cases.
These engines, while being a wedge-head, had a unique combustion chamber that resulted from a valve angle of only 6°. This was much flatter than the 23° of the small-block Chevrolet and 20° of the Ford small-block wedge heads. This very open and flat chamber was fuel efficient and had lower than average emissions output. It was the only GM engine to meet US emission standards using a carburetor all the way up to 1990.
The first second-generation Olds V8 to be released was the 1964 330 cu in (5.4 L) which Olds called the "Jetfire Rocket". It was released one year earlier than the tall deck 425 and introduced the standard 3.385 in (86.0 mm) stroke and used a 3.938 in (100.0 mm) bore and was produced through 1967. 330s were painted gold and had forged steel crankshafts. While the 4 barrel versions had a larger diameter harmonic damper, the 2 barrel versions used only a balancer hub without the rubberized outer ring.
The 400 cu in (6.6 L) version was the second tall-deck "big-block" Olds. Two distinct versions of the 400 CID engine were made:
All 1965-1969 Olds 400's were painted bronze.
The 1967 4-4-2 Rocket was a 400 cu in (6.6 L) V8.
The 425 cu in (7.0 L) big-block was the first tall-deck "big block," produced from 1965 through 1967. It is arguably the best engine Olds made in the muscle car era, although it never made it into a "muscle car". It used a 4.126 in (104.8 mm) bore and 3.975 in (101.0 mm) stroke. Most 425s were painted red, though the 1966 and 1967 Toronado units were light blue. All 425 engines were fitted with forged steel crankshafts with harmonic balancers.
The standard 1965-1967 425 cu in (7.0 L) was called the Super Rocket, and was the most powerful engine option for the Oldsmobile 88 and 98 of 1965-1967. Compression ratios of 9.0:1 at 310 hp (230 kW) or 10.25:1 at 360 hp (270 kW) were available in the U.S.
A special 1965-1967 425 cu in (7.0 L) V8 was the Starfire engine. The main distinguishing features of this engine were a slightly different camshaft profile from the standard ultra high compression engine and factory dual exhaust. This engine was only available in the Oldsmobile Starfire. It shared the same compression ratio of the Toronado Rocket at 10.5:1. It also used the .921 in lifter bore size of the Toronado Rocket.
Another 1967 425 cu in (7.0 L) V8 was the Ultra High Compression Toronado Rocket. Unlike all other 425s, this version was painted slate blue metallic. The Toronado 425 engines had the same 0.921 in (23.4 mm) diameter lifters of the first-generation Oldsmobile engines rather than the standard 0.842 in (21.4 mm). This let the engineers increase the ramp speed of the camshaft for more power, 385 hp (287 kW), without sacrificing idle or reliability.
A larger big-block was introduced for 1968 as the Rocket 455 at 455 cu in (7.5 L) to replace the 425s. It kept the 425's 4.126 in (104.8 mm) bore and bumped the stroke to 4.25 in (108 mm). Output ranged from 275 to 400 hp (199 to 298 kW). Initially the paint was red, except in the Toronado applications, where they were painted metallic blue; 1970-1976 versions were metallic blue at first, then nonmetallic blue. The "Rocket" name disappeared from the air cleaner identification decal after 1974. Although production of the 455 ended in 1976, a small number were produced through 1978 for power equipment use.
Produced from 1968–1980, the Rocket 350 was entirely different from the other GM divisions' 350's. It used a 4.057 in (103.0 mm) bore and Oldsmobile small-block standard 3.385 in (86.0 mm) stroke for 350 cu in (5.7 L). Output ranged from 160-325 hp (119-242 kW). 1968-1974 350s were painted gold; 1975-1976 350s were metallic blue like the 455; 1977-1980 models were painted GM Corporate Blue. The "Rocket" name disappeared from the air cleaner decal in 1975, the same year that the catalytic converter was added to the emission control systems. The early Oldsmobile 350s made from 1968-1976 are more desirable engines with heavy castings, beefier crankshafts, and better flowing heads. The later 1977-1980 350 had the "lightweight" castings, including a thinner block with large "windows" in the main bearing bulkheads, crack-prone head castings which were actually manufactured by Pontiac Motor Division (castings are marked "PMD"; these heads were also used on the 260), and a lightened crankshaft.
Oldsmobile's own L34 350-cubic-inch (5.7 L) V8 was used in the 1979 Hurst/Olds models. The L34 used a 4-barrel carburetor and produced 160–170 hp (120–130 kW) and 275 ft·lbf (373 N·m).
The 455 "big block" Olds V8 was replaced in 1977 with the 403 cu in (6.6 L) "small block" V8. It used a wide 4.351 in (110.5 mm) bore, the largest ever used in a small-block V8, with the Olds small-block standard deck and 3.385 in (86.0 mm) stroke. The bore was so wide that the cylinder walls were "siamesed" (similar to another GM 400 CID small block engine) — there was no space for coolant flow between the cylinders. This sometimes led to overheating problems. Some very early 403s were painted metallic blue like the 455, but most were painted GM Corporate Blue.
The Olds 403 was used by Buick and Pontiac in addition to Oldsmobile. The engine was only produced through 1979. Output was 185 hp (138 kW) and 320 lb·ft (430 N·m). The Toronado version of the 1977 Oldsmobile 403 engine was fitted with a crank triggered ignition system. Parts peculiar to this system include a toothed disc between the harmonic balancer and the crank pulley, the adjacent sensor, a special distributor, an engine temperature sensor, and a rudimentary computer mounted inside the car, under the dash. No other years or models were provided with this system.
A smaller 260 cu in (4.3 L) V8 was produced in 1975 by decreasing the bore to just 3.5 in (89 mm). This was the first powerplant to use the smaller Rochester Dualjet two-barrel carburetor; all 260s used it. Production of the 260 V8 ended in 1982 when the 307 became the only gasoline V8 in Oldsmobile's line.
The 260 was designed for economy and it was the first engine option above the 3.8L Buick V6 standard in many Oldsmobile models by the late 1970s. While the 260s were not very powerful compared to the larger 350 and 403 V8s, fuel economy was almost as good as the base V6. Compared to the V6, the 260 was also smoother-running, and far more durable.
Most 260s were coupled to the Turbo Hydramatic 200. A 5-speed manual transmission was also available with some 260-equipped vehicles.
The LV8 was a 260 cu in (4.3 L) version produced from 1975-1982. It produced just 105 hp (78 kW) and 205 lb·ft (278 N·m).
A slightly larger 307 cu in (5.0 L) version was introduced in 1980. It uses a 3.8 in (97 mm) bore (in common with the Buick 231 V6 and 350 V8) with a 3.385 in (86.0 mm) stroke. Some early 307s were painted GM Corporate blue, but most were painted satin black. It was used in most Oldsmobile models, as well as those from Buick, Cadillac, Chevrolet, and Pontiac. Every 307 used a four-barrel carburetor, generally a variant of the Rochester Quadrajet, usually the CCC (Computer Command Control) Quadrajet.
The output of the 307 cu in (5.0 L) was not particularly high in terms of horsepower. For example, the stock (non-high-output, VIN "Y") 307 cu in (5.0 L) in the 1983 Oldsmobile 98 was a mere 140 hp (100 kW), although in that year a high-output model (VIN "9") was available producing a nominal 180 hp (130 kW), at approximately 245 lb·ft (332 N·m) torque. The final 1990 configuration was rated at 140 hp (100 kW) at 3200 rpm and 255 lb·ft (346 N·m) of torque at 2000 rpm. The combination of good low-RPM torque, the Quadrajet four-barrel carburetor, and the THM-200-4R three speed plus overdrive automatic transmission having a lockup torque converter allowed for fairly good performance, and fuel economy considered reasonable for the era, even in the larger and heavier model cars.
Oldsmobile used the popular LV2, a 307-cubic-inch (5.0 L) engine, commonly known by the VIN code "Y", from 1980-1990. It was used by every domestic GM automobile marque. Roller lifters, floating piston wrist pins, and swirl port intake runners were added in 1985.
The 307 "Y" produced 148 hp (110 kW) and 250 lb·ft (340 N·m) in 1980-1984 models and 140 hp (100 kW) and 250 lb·ft (340 N·m) in 1985-1990s. All LV2s feature a 4-barrel carburetor.
The LG8 was a modern 307 cu in (5.0 L) High-Output derivative of the LV2 produced from 1983 to 1987. Performance modifications included a "hot" camshaft (in reality, just a camshaft used in various applications during the '70s with .440"/.440" lift and 196°/208° duration at .050"), stiffer valve springs, a larger vibration damper (same as all '73-'79 350s, 403s, and 455s), a Y-pipe dual-outlet exhaust system, and richer secondary metering rods in the carburetor. It was offered in the Hurst/Olds version of the Oldsmobile Cutlass Calais and in the 442 version of the Oldsmobile Cutlass Salon. Output for 1983-1985 was 180 hp (130 kW) and 245 lb·ft (332 N·m). Revisions to the engine for 1986 included roller lifters with a slightly smaller camshaft (.435"/.438" lift and 194°/210° duration at .050"), new heads with smaller, swirl-port intake runners, floating piston pins, and larger piston dishes for lower compression (8.0:1 v. 8.4:1). These changes increased torque to 250 lb·ft (340 N·m) but lowered power to 170 hp (130 kW), while lowering the RPM at which peak power and torque was achieved.
The GenII Oldsmobile V8 ended production in 1990. The company later introduced a new vehicle, the Oldsmobile Aurora, with a new generation of V8 power. Based on the Cadillac Northstar engine, the Oldsmobile Aurora engine was a DOHC design.
From the 1950s through the late 1970s, each GM division had its own V8 engine family. Many were shared among other divisions, but each design was unique:
GM later standardized on the later generations of the Chevrolet design:
|Wikimedia Commons has media related to Oldsmobile V8 engine.|