Chevrolet 90-Degree V6 engine
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http://en.wikipedia.org/wiki/Chevrolet_ ... _V6_engineChevrolet 90° V6 engine Manufacturer General Motors
Production 1978–
Displacement 200 cid (3.3 L)
229 cid (3.8 L)
262 cid (4.3 L)
Cylinder bore 3.50 in (89 mm)
3.736 in (95 mm)
4.00 in (102 mm)
Piston stroke 3.48 in (88 mm)
Cylinder block alloy Iron
Cylinder head alloy Iron
Valvetrain OHV
The Chevrolet 90° V6 family of engines began in 1978 with the Chevrolet 200 cid (3.3 L) V6 as the base engine for the all new 1978 Chevrolet Malibu. This engine family is still produced today, as the 4.3 L V6 engine used in Chevrolet and GMC trucks and vans.
These engines have a 90° vee block with 12 valves activated by a pushrod valvetrain. All engines have cast iron blocks and cylinder heads. The engines are based on the Chevrolet Small-Block engine, and the V6 is formed by the removal of the #3 and #6 cylinders. The V6s share the same 4.4" bore spacing and 9.025" deck height as the V8 engines. Many parts are interchangeable between the 90° V6 and the small block V8 including valvetrain components, bearings, piston assemblies, lubrication and cooling system components, and external accessories.[1] The 90-degree V6 engine uses the same transmission bellhousing pattern as the Chevrolet small-block V8 engine. The oil pan dipstick is located on the passenger side above the oil pan rail; this design was phased in on both the V6-90 and Small Block Chevrolet assembly lines sharing the same casting dies. All the engines use a 1-6-5-4-3-2 firing order.[2] The engines in this family are longitudinal engines, and have only been used in rear-wheel drive cars and trucks.
Contents
[hide]
1 3.3L (200 CID)
2 3.8L (229 CID)
3 4.3L (262 CID)
3.1 LB1 and LB4
3.2 LU2
3.3 L35 CPI
3.4 L35 and LF6 SCPI
3.5 LU3 and LG3 MPFI
3.6 Turbocharged LB4 4.3L V6
4 Notes
5 References
[edit] 3.3L (200 CID)
Introduced in 1978, the 200 cid replaced the larger 250 cid as the base engine for Chevrolet's new downsized intermediate line. The 200 cid used a unique 3.5" bore and a 3.48" stroke (the Chevrolet 305 cid and 350 cid V8 engines shared the same stroke dimension). These bore and stroke dimensions were later used by the 267 cid V8 Cheverolet engine. Also like the small block V8 engines, the 200 cid V6 used 2.45" main bearings and 2.10" rod bearing diameters.
Being a 90-degree V6, Chevrolet took steps to eliminate the rough running tendencies of the 200. The crankshaft has each of its connecting rod throws offset by 18 degrees for each pair of rods. This required the connecting rods to have 0.050" narrower ends as well as a thrust bearing to be installed between each pair of rods. However, the connecting rods were still the same 5.7" in length as most other small block Chevrolet V8 engines. This produced an engine that with a semi-even fire sequence of 132 degrees/108 degrees.[2]
The 200 cid V6 was only produced for 1978 and 1979. It was only ever available with a 2-barrel carburetor. In 1978, the 200 cid used the Rochester 2GC carburetor and in 1979 it used a Rochester Dualjet carburetor. The smaller Dualjet carburetor caused a slight decrease in power.
Year Horsepower Torque Bore and Stroke Carburetor Compression Ratio
1978 95 hp (71 kW) @ 3800 rpm 160 lb·ft (217 N·m) @2000 rpm 3.50" x 3.48" 2-BBL 2GC 8.20:1
1979 94 hp (70 kW) @ 4000 rpm 154 lb·ft (209 N·m) @2000 rpm 3.50" x 3.48" 2-BBL M2ME 8.20:1
[edit] 3.8L (229 CID)
The 229 cid engine was first introduced for the 1980 model year and was produced until 1984. This engine replaced the 250 cid in full-size Chevrolets and Camaros as the new base V6. Additionally, the intermediate Chevrolet Malibu and Monte Carlo also used the 229 cid as a replacement for both the 200 cid V6, and the 231 cid Buick V6. Both the 231 cid Buick V6 and the 229 cid Chevrolet V6 are 90 degree V6 engines, and both are often referred to as the 3.8L V6. These engines should not be confused as being the same, and are completely unique engine designs.
The 229 cid has a 3.736" bore and a 3.48" stroke, identical to the Chevrolet 305 cid V8 engine. The 229 cid used the same 2.45" main bearing and 2.10" rod bearing diameters as the 200 cid V6 engine. Also like the 200 cid V6, the 229 cid used the same crankshaft with the 18 degree offset throws and the same 5.7" connecting rods with 0.050" narrowed ends. It came equipped with 1.84" intake valves and 1.50" exhaust valves. The 229 cid V6 was only equipped with a 2-barrel carburetor. For 1980 the 229 cid used a mechanical Dualjet. From 1981 - 1984 the electronic Dualjet was used along with the GM's CCC (Computer Command Control) system. The 229 cid was rated between 110 and 115 hp (86 kW).
Year Horsepower Torque Bore and Stroke Carburetor Compression Ratio
1980 115 hp (86 kW) @ 4000 rpm 175 lb·ft (237 N·m) @ 2000 RPM 3.736" x 3.48" 2-BBL M2ME 8.60:1
1981–1982 110 hp (82 kW) @ 4200 rpm 170 lb·ft (230 N·m) @ 2000 RPM 3.736" x 3.48" 2-BBL E2ME 8.60:1
1983–1984 110 hp (82 kW) @ 4000 rpm 190 lb·ft (258 N·m) @ 1600 RPM 3.736" x 3.48" 2-BBL E2ME 8.60:1
[edit] 4.3L (262 CID)
The 4.3L (262 cid) V6 is the last and most successful engine in the Chevrolet 90-degree V6 engine family. This engine was introduced in 1985 as a replacement for the 229 cid V6 in the full-size Chevrolet and the Chevrolet El Camino. It also replaced the 250 cid in the Chevrolet full-size trucks and full-size vans as the new base six cylinder engine.
The 4.3L V6 has a 4.00" bore and a 3.48" stroke, identical to the 350 cid Chevrolet V8 engine. To create a true even fire engine, Chevrolet produced a crankshaft with 30 degree offsets between each rod pin. Consequentially, rod journals were increased to a larger 2.25". The connecting rods used on the 4.3L are therefore unique to this engine, being 5.7" in length, but having the larger 2.25" journals. The 4.3L also used larger valves than the 229 cid V6, with a 1.94" intake valve and a 1.50" exhaust valve.[2]
In 1986 and 1987, the 4.3L engine saw engine design upgrades similar to the Chevrolet small block V8. In 1986, the rear main crankshaft oil seal was changed from a two piece to a one piece seal. Some 1985 model year vehicles would have a 1986 engine due to service replacement - cylinder blocks were shipped with oil pans.[3] 1987 saw new center bolt valve covers and hydraulic roller lifters.[4]
For the 1992 model year, the 4.3L had its block design modified to allow a balance shaft to be installed.[5] Even though the 4.3L is an even fire V6, the 90 degree block layout is not ideal for smoothness. The balance shaft on the 4.3L is installed above the top timing gear, and runs through the top of the lifter valley. It is gear driven off the timing chain, and therefore a new timing chain cover was designed for these balanced 4.3L V6s.
[edit] LB1 and LB4
In 1985, the 4.3L was either equipped with throttle-body fuel injection, RPO LB4 or a Rochester Quadrajet 4-Barrel carburetor, RPO LB1. The Chevrolet full-size sedans and the Chevrolet El Camino used the LB4 rated at 130 hp (97 kW). Pick-ups and Vans used the LB1 version rated at 155 hp (116 kW). The LB1 used in trucks and vans was referred to as Vortec in Chevrolet literature (named after a combustion chamber design known as a swirl port which twists the fuel mix from the intake ports as introduced on the Cavalier 2.0L motor), and this name continued to be used with all truck and van 4.3L V6s until present day.
In 1986, the 4.3L engine used in the Chevrolet Caprice and El Camino saw an increase in power to 140 hp (100 kW). This engine remained unchanged until 1990 when it was last used in taxi and Police Chevrolet Caprices. In 1986 the Chevrolet Astro and GMC Safari vans used the fuel injected LB4 instead of the LB1. In 1987, the Chevrolet full size pick-ups and full-size vans were upgraded to use the LB4 throttle-body injection version of the 4.3L. From 1987 onwards LB4s output was 160 hp (120 kW) for pickups, while full-size vans were rated at 150 hp (110 kW). In 1988 the S-series trucks and S-Blazer and Jimmys had the LB4 4.3L as an available option (the accessory drive was upgraded to a serpentine belt drive), which later replaced the 2.8 as the base V6. The LB4 continued until 1996 with minor variations in power, but without any major change.
Year Horsepower Torque Fuel System Compression Ratio RPO Applications
1985–1986 155 hp (116 kW) @ 4000 rpm 230 lb·ft (312 N·m) @ 2400 RPM 4-BBL 9.3:1 LB1 1,2,3
1985 130 hp (97 kW) @ 3600 rpm 210 lb·ft (285 N·m) @ 2000 RPM TBI 9.3:1 LB4 4,5
1986–1990 140 hp (100 kW) @ 4000 rpm 225 lb·ft (305 N·m) @ 2000 RPM TBI 9.3:1 LB4 4,5
1987–1988 145 hp (108 kW) @ 4200 rpm 225 lb·ft (305 N·m) @ 2000 RPM TBI 9.3:1 LB4 5
1986 160 hp (120 kW) @ 4000 rpm 235 lb·ft (319 N·m) @ 2400 RPM TBI 9.3:1 LB4 3
1987–1992 155 hp (116 kW) @ 4000 rpm 230 lb·ft (312 N·m) @ 2400 RPM TBI 8.6:1 LB4(w/C6P emissions 2500&3500 series only) 2
1987–1992 160 hp (120 kW) @ 4000 rpm 235 lb·ft (319 N·m) @ 2400 RPM TBI 9.1:1 LB4 1,3,6,7
1993–1995 155 hp (116 kW) @ 4000 rpm 230 lb·ft (312 N·m) @ 2000 RPM TBI 9.1:1 LB4 2
1993–1995 165 hp (123 kW) @ 4000 rpm 235 lb·ft (319 N·m) @ 2000 RPM TBI 9.1:1 LB4 1,3,6,7
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