The Chevrolet 4.3 engine was based on the "Small Block" engine line. During the late 1970s, Chevrolet engineered a new engine that would be lighter and leaner. This was in response to the fuel and energy crunch of the era. Taking from the original V8 engine, the V6 engine was made by truncating number 3 and 36 cylinders. This was first released with a 200 cc displacement in 1980. In 1985, the V6 was upgraded to 262cc displacement or 4.3 liters. The V6 was now also called the "Vortec" engine, which was eventually used as the name for all the predecessors.
Development of the Chevy 4.3 Engine
In 1986, Vortec engine technology was first used on the 4.3L V6 engine. As the name implies, it created a vortex inside the combustion chamber. The basic idea of the Vortec engine was to create a better blend of air and fuel that resulted in more power and efficiency.
By 1987, the Chevy 4.3 became a 90-degree motor with a throttle-body injection. It was used in full-sized trucks and vans. In 1991, engine vibration was reduced with a balance shaft. In 1996, it became a sequential (multi-port) injection, OBD-II compliant engine. It also featured an engine management computer system, a composite intake manifold, roller rockers, and powder metal rods.
Flywheels, Bellhousings and Transmissions
The Chevy 4.3 V6 used an 11-inch clutch disc (168 tooth flywheel), instead of the usual 10.5-inch clutch disc (153 tooth flywheel). The bigger clutch required a larger bellhousing to provide the needed clearance. Like the Small Block V8, the 4.3 was compatible with almost every transmission available. This included both manual and automatic transmissions, such as the SAS SM420, SM465, Ford T18, Ford NP435, T90, T150, T176, AX15, NV3550, TH350, TH400, TH700R4 and 4L60-E.
Technical Specifications
The 2010 4.3L Vortec engine had a compression ratio of 9.4:1. The bore and stroke were 4 inches x 3.48 inches. The block, cylinder head and intake manifold were made of cast iron. The fuel system was OEM defined and used regular unleaded, propane and natural gas. Depending upon the fuel used, it could generate varying power and torque. Gasoline produced a maximum of 190 horsepower with 253 ft-lbs. of torque, while propane generated 183 horsepower with 247 ft-lbs. of torque. Natural gas was able to produce 164 horsepower with 230 ft-lbs. of torque.
