Chevy 4.3 Vortec Head Torque Specsby Anne Davis
In 1998, GM began producing a line of engines with the name "Vortec." This line of engines, which includes the 4.3-liter V-6, creates a vortex within the engine's combustion chambers to mix the air and fuel more effectively. The 4.3-liter V-6 was the manufacturer's first available Vortec engine.
In an engine, the cylinder head, also referred to as the head, sits over the engine's cylinders on the engine block. The entire component consists of a platform that includes valves and spark plugs. Manufacturers establish torque specifications to ensure that all bolts and nuts are tightened to to the necessary and appropriate degree. Torque refers to the amount of force required to rotate an object, in this case a nut or a bolt, around an axis point or pivot.
In engines manufactured before 1996, the cylinder head bolts requires 65 foot-pounds of torque. In engines made during or after 1996, the cylinder head bolts 22 foot-pounds of torque. In either case, the bolts must be torqued twice.
The four inner bolts of the exhaust manifold in all 4.3L V6 engines attach to the cylinder head with 30 foot-pounds of torque, and all other bolts join with 20 foot-pounds. The intake manifold bolts require 33 foot-pounds of torque to join properly with the cylinder head. The spark plugs require 11 foot-pounds of torque to attach to the cylinder head. The valve covers in pre-1996 engines need 7.5 foot-pounds of torque, and in 1996 and later engines, 8.83 foot-pounds.
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