4.3 Liter Head Bolt Torque Specs
by Anne Davis
Both Ford and General Motors manufacture 4.3 liter engines. Ford's 4.3L V8 was introduced in 1962 and placed in full-size sedans such as the Ford Falcon. GM manufactures three 4.3 liter engines--a 262 cubic inch displacement V8, a 262 cubic inch displacement V6 and a 265 cubic inch displacement V8. The 262 cubic inch V6 is a member of GM's Vortec engine family.
Helical Sequence
Certain engine components, usually those involving the head, require that the bolts be torqued in a helical sequence. For this, you begin torquing with the center-most bolt or bolts on the component, and work your way outward in both directions. If there are multiple steps, torque everything to the first specification, then torque all of the bolts in the same order to the second specifications.. Wait approximately 15 minutes between each step to give the bolts time to stretch and settle.
Ford 260 CID V8
In Ford's 4.3 liter V8 engine, the cylinder head attaches to the engine block in three steps with a helical sequence: first to 45 ft-lbs of torque, then to 55 ft-lbs and finally to 70 ft-lbs.
The engine's intake manifold bolts to the cylinder head in three steps: first to 12 ft-lbs of torque, then to 20 ft-lbs and finally to 22 ft-lbs. The valve cover requires 4 ft-lbs of torque to attach properly to the cylinder head.
GM 262 CID V8
In GM's 4.3L 262 cubic inch displacement V8 engine, the cylinder head bolts to the engine block in three distinct steps in a helical sequence: first to 25 ft-lbs of torque, then to 45 ft-lbs and lastly to 65 ft-lbs.
The exhaust manifold requires 20 ft-lbs and the intake manifold requires 33 ft-lbs of torque to attach to the cylinder head. The valve cover bolts to the cylinder head with 5 ft-lbs of torque.
GM 265 CID V8
In GM's 265 cubic inch displacement V8 engine, the cylinder head bolts to the engine block first with 25 ft-lbs of torque, then with 45 ft-lbs and finally with 65 ft-lbs. These steps are carried out in a helical sequence.
The outer exhaust manifold bolts require 20 ft-lbs of torque, the inner exhaust manifold bolts require 30 ft-lbs and the intake manifold bolts require 33 ft-lbs of torque to join with the cylinder head. The valve cover-to-cylinder head bolts receive 5 ft-lbs of torque.
GM 262 CID V6
In GM's 4.3 liter V6 engines manufactured in or before 1995, the cylinder head bolts to the engine block with 65 ft-lbs of torque. In engines produced after 1995, the bolts all require 22 ft-lbs to join properly with the engine block.
The exhaust manifold bolts require first 11 ft-lbs and then 22 ft-lbs of torque to attach to the cylinder head properly. In engines made before 1996, the valve cover bolts receive 7.5 ft-lbs of torque. In those made in or after 1996, the same bolts receive 8.83 ft-lbs to attach to the cylinder head.
References
Writer Bio
Anne Davis writes pieces on domestic and international travel, automotive maintenance, education and health. She graduated with a Bachelor of Arts in English and history, and is pursuing graduate study in a related field.
