Chapter 13 Cylinder head construction Valve train construction

Chapter 13

�Cylinder head construction �Valve train construction �Intake manifold construction �Exhaust manifold construction

Engine Top End Includes the cylinder head, valve train, valve cover, and intake and exhaust manifolds

�A bare cylinder head is a head casting with all of its parts removed �If a cylinder head becomes damaged, the technician may need to install a new bare head �All the old, reusable parts can be removed and installed in the new head

Cylinder Head and Parts

Cylinder Head Construction This cast aluminum head has four-valve combustion chambers

Cylinder Head Construction This cast iron head has two-valve combustion chambers

Valve Guide Construction �There are two basic types of valve guides: integral valve guides pressed-in valve guides

Integral Valve Guide �Part of the cylinder head casting �Simply a hole machined through the cylinder head �Very common because of its low production cost

Pressed-In Valve Guide �Separate sleeve forced into a hole machined in the cylinder head �Made of cast iron or bronze �During repair, a worn guide can be pressed out and a new guide can be quickly pressed in

Valve Seat Construction �Valve seats can be integral or �Integral valve seat pressed-in machined portion of the cylinder head casting �Pressed-in valve seat separate part that is forced into a recess cut into the head commonly used in aluminum heads

Valve Seats and Guides

Valve Seat Angle �Angle formed by the face of the seat �Most engines use a 45º angle �Some high-performance engines use seat angles of 30º