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|Also called||GM Vortec engine|
|Predecessor||GM LT engine, Chevrolet Small-Block engine, Chevrolet Big-Block engine|
|Also called||GM Vortec engine|
|Predecessor||GM LT engine, Chevrolet Small-Block engine, Chevrolet Big-Block engine|
The GM LS engine family is an engine design intended as the only V-8 engine used in General Motors' line of rear-wheel-drive cars and trucks. The LS series was a "clean sheet" design with little in common in terms of shared parts with the classic Chevrolet small block V8. The basic layout owes a good deal to the essential concept of Ed Cole's original small-block design of 1954-55, though the LS engine also uses design cues from Buick, Oldsmobile and Pontiac engines. Some LS engines are all-aluminum, especially the performance oriented engines, while others are cast iron, and all LS engines have six-bolt main bearing caps.
The LS engine has been the sole powerplant of the Chevrolet Corvette since 1997 and has seen use in a wide variety of other General Motors vehicles, ranging from sport coupes to full size trucks. Due to the engine's relatively compact external dimensions compared to its displacement and power output, the engine family is also a popular choice for kit cars, hot rods, buggies, and even light aircraft.
The Generation III V-8 engines (It should be noted that Buick, Olds and Pontiac (301) all had small block engines that, for some unknown reason, GM fails to count in its "generation" numbers) that replaced the Gen II-LT family in 1997 and Gen I completely by 2003. Like the previous two generations, the Buick, Oldsmobile and Pontiac small blocks, the gen III/IV can be found in many different brands. The engine blocks were cast in aluminum for car applications, and iron for most truck applications (notable exceptions include the Chevrolet TrailBlazer SS, Chevrolet SSR and a limited run of Chevrolet/GMC Extended Cab Standard Box Z71 Trucks). The architecture of the LS series makes for an extremely strong engine block with the aluminum engines being nearly as strong as the iron generation I and II engines and with the iron LS engines far exceeding the capabilities of the previous two generations. The LS engine also used coil-near-plug ignition to replace the distributor setup of all previous small-block based engines. The traditional five-bolt pentagonal cylinder head pattern was replaced with a square four-bolt design ( much like the 64-90 Oldsmobile V-8 ) , and the pistons are of the flat-topped variety (in the LS1, LS2, LS3, LS6, LS7, LQ9 and L33), while all other variants, including the new LS9 received a dished version of the GM hypereutectic piston. The cylinder firing order was changed to 1-8-7-2-6-5-4-3, so that the LS series now corresponds to the firing pattern of other modern V8 engines (for example the Ford Modular V8).
The first of the Generation IIIs, the LS1 was the progenitor of the new architecture design that would transform the entire V8 line and influence the last of the Big Blocks.
The Generation III 5.7 L shares little other than similar displacement, external dimensions, and rod bearings, with its predecessor (LT1). It is an all-aluminum 5,665 cc (5.665 L; 345.7 cu in) pushrod engine with a bore of 3.898 in (99.0 mm) and a stroke of 3.62 in (92 mm).
When introduced in the 1997 Corvette the LS1 was rated at 345 hp (257 kW) at 5,600 rpm and 350 lbf·ft (470 N·m) at 4,400 rpm. After improvements to the intake and exhaust manifolds in 2001 the rating improved to 350 hp (260 kW) and 365 lbf·ft (495 N·m). The LS1 was used in the Corvette from 97-04. It was also used in 98-02 GM F-Body (Camaro & Trans Am) cars with a rating of 305–325+ HP, which was rumored to be conservative. The extra horsepower was claimed to come from the intake ram-air effect available in the SS and WS6 models. In Australia, continuous modifications were made to the LS1 engine throughout its lifetime, reaching 382 bhp (285 kW) in the HSV's YII series, and a Callaway modified version named "C4B" was fitted to HSV GTS models producing 402 bhp (300 kW).
The LS6 is a higher-output version of GM's LS1 engine and retains the same capacity. The initial 2001 LS6 produced 385 bhp (287 kW) and 385 lbf·ft (522 N·m), but the engine was modified for 2002 through 2004 to produce 405 bhp (302 kW) and 400 lbf·ft (540 N·m) of torque. The LS6 was originally only used in the high-performance C5 Corvette Z06 model, with the Cadillac CTS V-Series getting the 400 bhp (300 kW) engine later. The V-Series used the LS6 for two years before being replaced by the LS2 in 2006. For 2006, the Z06 replaced the LS6 with the new LS7. The LS6 shares its basic block architecture with the GM LS1 engine, but other changes were made to the design such as windows cast into the block between cylinders, improved main web strength and bay to bay breathing, an intake manifold and MAF-sensor with higher flow, a camshaft with higher lift and more duration, a higher compression ratio of 10.5:1, sodium filled valves, and a revised oiling system better suited to high lateral acceleration. LS6 intake manifolds were also used on all 2001–2002 LS1 engines. The casting number, located on the top rear edge of the block, is 12561168. Applications:
The 4.8 L and the 5.3 L are smaller truck versions of the LS1 and were designed to replace the 305 and the 350 in trucks. Both the 4.8 L and the 5.3 L share the same engine block and heads. Although the block of the 4.8 L/5.3L looks similar to the LS1, they are not the same.
The Vortec 4800 LR4 is a small block V8 truck engine. Displacement is 4.8 L (290 cu in) with a 96.01 mm (3.779") bore and 83 mm (3.268") stroke. It is the smallest of the Generation III Vortec truck engines and was the replacement for the 5.0 L 5000 L30. The Vortec 4800 produces 270 horsepower (200 kW) to 295 horsepower (220 kW) and 285 lbf·ft (386 N·m) to 305 lbf·ft (414 N·m), depending on the model year and application.
The Vortec 5300 is a V8 truck engine. It is a stroked (by 9 mm) version of the Vortec 4800 and replaced the 5700 L31. Power output is 285-315 hp (223-239 kW) and torque is 335 lbf·ft (454 N·m) to 350 lbf·ft (470 N·m). Displacement is 5.3 L (5,328 cc (325.1 cu in)) from 96.01 mm (3.779") bore and 92.00 mm (3.622") stroke.
The 6.0 L is a larger truck version of the LS1, with the exception that the blocks were cast of iron, and was designed to bridge the gap between the new small blocks and big blocks in truck applications. There were two version of this engine: the LQ4 and the LQ9, the latter being more performance oriented. Although the block of the 6.0L looks similar to the LS1, they are iron instead of aluminum.
The Vortec 6000 is a V8 truck engine. Displacement is 6.00 L (366 cu in) from 101.6 mm (4.00) bore and 92 mm (3.622") stroke. It is an iron/aluminum (1999 & 2000 model year engines had cast iron heads) design and produces 300 horsepower (220 kW) to 345 horsepower (257 kW) and 360 lbf·ft (490 N·m) to 380 lbf·ft (520 N·m).
In 2005, the Generation III was superseded by the Generation IV. This category of engines has provisions for high-displacement ranges up to 7,011 cc (7.011 L; 427.8 cu in) and power output to 638 bhp (476 kW). Based on the Generation III design, Generation IV was designed with displacement on demand in mind, a technology that allows every other cylinder in the firing order to be deactivated. It can also accommodate variable valve timing.
A 3-valve per cylinder design was originally slated for the LS7, which would have been a first for a GM pushrod engine; but the idea was shelved owing to design complexities and when the same two-valve configuration as the other Generation III and IV engines proved to be sufficient to meet the goals for the LS7.
This family of blocks were the first of the generation IV small block with the LS2 being the progenitor of this family and generation. This family of blocks has seen a wide range of applications from performance vehicles to truck usage.
The LS2 was introduced as the Corvette's new base engine for the 2005 model year. It also appeared as the standard powerplant for the 2005–2006 GTO. It produces 400 bhp (300 kW) at 6000 rpm and 400 lb·ft (542 N·m) at 4400 rpm from a slightly larger displacement of 5,967 cc (5.967 L; 364.1 cu in). It is similar to the high-performance LS6, but with improved torque throughout the rpm range. The LS2 uses the "243" casting heads used on the LS6 (although without the sodium filled valves), a smaller camshaft, and an additional 18 cubic inches. The compression of the LS2 was also raised to 10.9:1 compared to the LS1s 10.25:1 and the LS6s 10.5:1. The LS2s in the E-series HSVs are modified in Australia to produce 412 bhp (307 kW) and 412 lbft . The LS2s in the Chevrolet Trailblazer SS and the Saab 9-7X Aero are rated at 395 bhp (295 kW) (2006–2007) or 390 bhp (290 kW) (2008–2009) and 400 lb·ft (542 N·m) of torque due to a different (sometimes referred to as a "truck") intake manifold that produces more torque at lower RPMs.
The LS2 is also used as the basis of the NASCAR Specification Engine that is used as an optional engine in NASCAR's Camping World Series East and West divisions starting in 2006, and starting in 2010 may also be used on tracks shorter than two kilometers (1.25 miles) in the Camping World Truck Series.
L76 was originally Holden's version of the 5,967 cc (5.967 L; 364.1 cu in) Generation IV engine. While displacement on demand technology was disabled on Holdens, this feature is enabled on the 2008 Pontiac G8 GT and subsequently refitted in the 2009 model Holdens with AFM enabled, but only on models fitted with the 6L80 Automatic Transmission. The engine also meets Euro III emissions requirements. Output is 348 bhp (260 kW) at 5600 rpm and 376 lb·ft (510 N·m) at 4400 rpm for the Holden variant, and 361 bhp (269 kW) and 385 lb·ft (522 N·m) for the G8 GT.
The L98 is a slightly modified version of the L76. Since Holden did not use the displacement on demand technology of the L76, some redundant hardware was removed to form the L98. Power increased to 362 bhp (270 kW) at 5700 rpm and 391 lb·ft (530 N·m) at 4400 rpm.
As of February 2009 Holden have used AFM in the L76 block which has been available in all automatic V8s
L77 engines were released in the Holden Commodore Series II VE range in both manual and automatic transition. The 2011 model year marks the return of the Chevrolet Caprice rear-wheel-drive police car and under its hood is a new version of a performance stalwart: The L77 6.0L Gen IV V-8. The L77 is similar to the L76 6.0L that was previously offered in North America in the Pontiac G8 GT; and the L76 is derived from the LS2 6.0L that was offered in the Pontiac GTO and 2005-07 Chevrolet Corvette. The L76 differed from the LS2 with its inclusion of Active Fuel Management (AFM) cylinder deactivation technology. The L77 retains AFM and adds FlexFuel capability, allowing it to run on E85 ethanol. The L77 is rated at 361 horsepower (269 kW) and 385 lb.-ft. of torque. Along with the performance that law enforcement personnel needs, the L77 delivers good efficiency, thanks to AFM. It allow the engine to operate on only four cylinders during certain light-load driving conditions, saving the fuel normally used to drive all eight cylinders. As with other members of the Gen IV engine family, one of the enablers of the L77’s balance of performance and efficiency is great airflow throughout. Intake flow was improved over previous engines by straightening out and optimizing the flow path from the intake manifold into the cylinder heads, while the exhaust ports are also designed for greater flow. The engine’s efficiency also optimizes emissions performance."
The generation IV Vortec 6000 is a V8 truck engine based on the LS2. Displacement is 6.0 L (370 cu in) from 101.6 mm (4.0 in) bore and 92 mm (3.6 in) stroke. It is an iron or aluminum engine block that has cast aluminum heads and can be equipped with variable cam phasing and/or Active Fuel Management.
This family of blocks is just an updated version of its generation III predecessor with generation IV updates and capabilities. Applications of this family were mainly for trucks but did see some mild performance usage in front-wheel-drive cars although with some modifications.
The Vortec 4800 LY2 is a Generation IV small block V8 truck engine. Like its LR4 predecessor, it gets its displacement from a 96.01 mm bore and 83 mm stroke. The smallest member of the Generation IV engine family, it is unique in that it is the only member of that family that use in trucks that does not feature either variable valve timing (until 2010) or Active Fuel Management.
The Generation IV Vortec 5300 engines are truck engines that share all the improvements and refinements found in other Generation IV engines. At present, four versions of the 5300 are in production: two iron block versions (LY5 and LMG) and two aluminum block versions (LH6 and LC9). All versions feature the Active Fuel Management system.
The LS4 is a 5,328 cc (5.328 L; 325.1 cu in) version of the Generation IV block. Though it has the same displacement as the Vortec 5300 LY5, it features an aluminum block instead of iron, and it uses the same cylinder head as the Generation III LS6 engine. The bellhousing bolt pattern differs from the rear-wheel drive blocks.
This engine is adapted for transverse front-wheel drive applications. According to GM, "The crankshaft is shortened 13 mm – 3 mm at the flywheel end and 10 mm at the accessory drive end – to reduce the length of the engine compared to the 6.0L. All accessories are driven by a single serpentine belt to save space. The water pump is mounted remotely with an elongated pump manifold that connects it to the coolant passages. Revised oil pan baffles, or windage trays, are incorporated into the LS4 to ensure that the oil sump stays loaded during high-g cornering." Active Fuel Management is also used. Output of this version is 303 hp (226 kW)/300 hp on LaCrosse Super and 323 lb·ft (438 N·m).
Inspired by the LS1.R in size and performance goals, this family of blocks was designed for race oriented performance. The only block that is in production is the LS7 with the LSX being only for aftermarket use. One unique feature of this family is that the cylinders are siamesed, no water passages between neighboring cylinders. This was done to increase both bore size and block strength.
The LS7 is a 7,008 cc (7.008 L; 427.7 cu in) engine, based on the Gen IV architecture. The block is changed, with sleeved cylinders and a larger 4.125in (104.775mm) bore and longer 4.00in (101.6mm) stroke than the LS2. The small-block's 4.4 in (110 mm) bore spacing is retained, requiring pressed-in cylinder liners. The crankshaft and main bearing caps are forged steel for durability, the connecting rods are forged titanium, and the pistons are hypereutectic. The two-valve arrangement is retained, though the titanium intake valves by Del West have grown to 2.20 in (56 mm) and sodium-filled exhaust valves are up to 1.61 in (41 mm).
Peak output is 505 hp (377 kW) at 6300 rpm and 470 lb·ft (640 N·m) at 4800 rpm with a 7100 rpm redline During GM's reliability testing of this engine in its prototype phase, the LS7 was remarked to have been repeatedly tested to be 8000 rpm capable, although power was not recorded at that rpm level, due to the constraints of the camshaft's hydraulic lifters and the intake manifold ability to flow required air at that engine speed.
After an extensive engineering process over several years, Holden Special Vehicles fitted the LS7 to a special edition model, the W427. The HSV-tuned engine produces 375 kW (503 hp) and 640 N·m (470 lb·ft), making it the most powerful car ever built in Australia. The W427 was unveiled at the Melbourne International Motor Show on 29 February 2008 and went on sale in August 2008.
The LS7.R engine is a variation of the LS7 used in the highly successful C6.R American Le Mans Series racecar. It was crowned as Global Motorsport Engine of the Year by a jury of 50 race engine engineers on the Professional Motorsport World Expo 2006 in Cologne, Germany.
At the 2006 SEMA show, GM Performance Parts introduced the LSX engine, an all-new cast-iron racing block based on the LS7 engine. It was designed with help from drag racing legend Warren Johnson. It offers displacements ranging from 364 cubic inches to 511 cubic inches (4.25 in (108 mm) Bore x 4.5 in (110 mm) Stroke) and is capable of withstanding 2,500 bhp (1,900 kW). This block incorporates two extra rows of head-bolt holes per bank for increased clamping capacity. The six bolt steel main caps are the same ones used on the LS7 engine. The engine debuted at the auto show in a customized 1969 Camaro owned by Reggie Jackson. The LSX will be available starting the second quarter of 2007, set to be available in authorized dealerships and retailers on March 31, 2007.
This family was designed as a replacement for the LS2 but enlarged to better accommodate variable valve timing and Active Fuel Management while still generating good performance. This family of engines has mainly seen duty in performance cars and high-end SUVs.
The 2007 Cadillac Escalade has a 6.2 L Vortec 6200 (RPO L92) (≈379 cu in) engine. It is an all-aluminum design which, while still a pushrod engine, boasts variable valve timing. The system adjusts both intake and exhaust timing between two settings. This engine produces 403 hp (301 kW) and 417 lb·ft (565 N·m) in the GMC Yukon Denali/XL Denali, Sierra SLT, and in the GMC Sierra Denali, and rated at 403 hp (301 kW) and 415 lb·ft (563 N·m) (441 hp with 93 octane[clarification needed] export version) in the Hummer and in the Cadillac Escalade. It is also available in the Chevrolet Silverado and Tahoe LTZ, with power ratings of 403 hp (301 kW) and 417 lb·ft (565 N·m) .
The LS3 was introduced as the Corvette's new base engine for the 2008 model year. It produces 430 bhp (321 kW; 436 PS) at 5900 rpm and 424 lb·ft (575 N·m) at 4600 rpm without the optional Corvette exhaust and is SAE certified. The block is an updated version of the LS2 casting featuring a larger bore of 4.06 in (103 mm) creating a displacement of 6,162 cc (6.162 L; 376.0 cu in). It also features higher flowing cylinder heads sourced from the L92, a more aggressive camshaft with 0.551-inch (14.0 mm) lift, a 10.7:1 compression ratio, a revised valvetrain with 6 mm (0.24 in) offset intake rocker arms, a high-flow intake manifold and 47 lb/hr fuel injectors from the LS7 engine.
The L76/L92/LS3 cylinder heads use 2.165 in (55.0 mm) intake valves, and 1.59 in (40 mm) exhaust valves. Improved manufacturing efficiency makes these heads cheaper than the outgoing LS6 heads, and severely undercuts aftermarket heads. The large valves, however, limit maximum rpm - 6000 in the L76 (with AFM), and 6600 in the LS3 (with hollow stem valves).
In addition to the above, a dual-mode exhaust package with a bypass on acceleration is available. The dual-mode exhaust uses vacuum-actuated outlet valves, which control engine noise during low-load operation, but open for maximum performance during high-load operation. The system is similar to the C6 Z06, but uses a 2.5 in (64 mm) diameter exhaust compared to the Z06's 3 in (76 mm). Power is boosted to 436 hp (325 kW) and 428 lb·ft (580 N·m) with this option.
From April 2008, Australian performance car manufacturer, HSV, adopted the LS3 as its standard V8 throughout the range, replacing the LS2. The LS3 received modifications for its application to HSV E Series models, producing 425 bhp (317 kW). The LS3 engine in the E Series II GTS (released September 2009) was upgraded to produce 436 bhp (325 kW). All HSV MY12.5 excluding the base Maloo and Clubsport variants have been upgraded to produce 436 bhp (325 kW).
The L99 is derived from the LS3 with reduced output but adds Active Fuel Management (formerly called Displacement on Demand), which allows it to run on only four cylinders during light load conditions.
The Gen IV LS9 is a supercharged 6,162 cc (6.162 L; 376.0 cu in) engine, based on the LS3; the LS7 block was not used due to the higher cylinder pressures created by the supercharger requiring the thicker cylinder walls of the LS3. Cylinder dimensions are now 4.06 in (103 mm) bore and 3.62 in (92 mm) stroke. It is equipped with an Eaton four-lobe Roots type supercharger and has a compression ratio of 9.1:1. Power output is rated 638 bhp (476 kW) at 6500 rpm and 604 lb·ft (819 N·m) at 3800 rpm. Note: GM previously used the LS9 RPO code on 1969 and later Chevrolet trucks (both 2WD and 4WD) including Blazers, Jimmys, Suburbans, as well as car carriers. The original LS9 was a 350 cu in V8, developing 350 hp and 425 Ft/lbs of torque.
The supercharged 6.2L LSA is similar to the LS9 and debuted in the 2009 CTS-V. The LSA has been SAE certified at 556 bhp (415 kW) at 6100 rpm and 551 lb·ft (747 N·m) at 3800 rpm. GM labels it "the most powerful ever offered in Cadillac’s nearly 106-year history". The LSA features a smaller 1.9L capacity supercharger rather than the 2.3 L variant of the LS9. Other differences include a slightly lower 9.0:1 compression ratio, single unit heat exchanger and cast pistons.
On February 9, 2011 Chevy Announced that the LSA will be used in the 2012 Camaro ZL1; it adds an additional 24 hp to make 580 hp, 30 hp over the original 550 hp rated ZL1, with some stock 550 hp examples in existence.
Iron block versions of both the Generation III and Generation IV V8 have also been used in trucks. These are usually branded as GM Vortec engines.
In 2007, wardsauto.com reported that the LS3 (used by 2008 Chevrolet Corvette) and Vortec 6000 LFA (used by 2008 Chevrolet Tahoe Hybrid) engines would be the final two designs in the Generation IV small-block engine family, and the future designs would be part of the Generation V engine family.
An experimental engine was built based on L92 engine from Cadillac Escalade, GMC Yukon Denali and Hummer H2, and reported to generate 450 bhp (340 kW) on gasoline via direct fuel injection, increased compression ratio to 11.5:1, and a modified engine controller.
In 2012, the first Small Block Gen 5 (official designation), designated LT1, was announced as the powerplant for the C7 Corvette. The new logo formally adopts the Small Block name for the engines. The Gen 5 now includes a 90 degree V6 variant displacing 4.3L - destined to replace the 1978-era Chevrolet 90 degree V6.
In the early production run of the LS-series engine, some engines encountered abnormal amounts of 'piston slap' - a problem caused by too much clearance between the cylinder bore and the piston. 'Piston slap' sometimes sounds more like a knock or the sound of a diesel engine running. It is typically worse when the engine is cold and lessens as the engine reaches operating temperature. The noise of 'piston slap' often is louder when listening for it below the oil pan.
Another common problem with the 04-06 5.3L engines was cracking cylinder heads. This is commonly called the 'Castech Head' failure on the internet. GM issued a TSB on this failure to help service techs identify the problem. The head casting (which can be viewed from the passenger side of the vehicle just in front of the valve cover) was 706. Some heads with this casting number would fail, but not all of them as GM had different suppliers for the same head. The failure was due to undetected porosity around the oil drains in the head.
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