Glossary “valve timing” Definition:
Actual opening and closing of the valves in relationship to the number of degrees of crankshaft rotation.

Glossary “valve stem height” Definition:
Measurement that reflects how much a valve and valve seat have been ground.

Glossary “valve stud boss” Definition:
The boss in the cylinder head that supports and holds the rocker-arm stud.

Glossary “valve tappet” Definition:
Term used for valve lifter.

Glossary “valve temperature” Definition:
The operational temperature of a valve that may reach 1,400¡ãF at the head and be as low as 100¡ãF at the stem.

Glossary “valve spring seat” Definition:
Area in the cylinder where the fixed end of the valve spring is placed.

Glossary “valve stem” Definition:
1). Device mounted in the rim or inner tube to provide a method of increasing or decreasing air pressure inside a tire. 2). The long, slim, round part of a valve.

Glossary “valve stem groove” Definition:
That part of the valve stem used to position the keepers and locate the valve retainer.

Glossary “valve stem guide” Definition:
Bushing or hole in which the valve stem is placed which allows lateral motion only.

Glossary “valve spring retainer lock” Definition:
Device on the valve stem that locks the valve spring retainer in place.

Glossary “valve spring installed height” Definition:
Measurement that increases with machining of the valve and valve seat. Shims can be used to restore the correct height and spring tension.

Glossary “valve spring retainer” Definition:
Device on the valve stem that holds the spring in place.

Glossary “valve seat” Definition:
Ring of hard metal to which the valve seals.

Glossary “valve seat insert” Definition:
A replacement valve seat.

Glossary “valve seat recession” Definition:
Tendency for some valves to contact the seat in such a manner as to wear away the seat.

Glossary “valve spool” Definition:
Spool-shaped valve such as that in a power-steering unit or other hydraulic units.

Glossary “valve spring” Definition:
Small coil spring that closes the valve and keeps the lifter in contact with the camshaft.

Glossary “valve retainer” Definition:
Term used for valve keeper or valve key.

Glossary “valve rotator” Definition:
Device that rotates the valve while the engine is running. See positive valve rotators.

Glossary “valve seal” Definition:
Device placed on the valve stem or guide to prevent excess oil from seeping into the clearance between the valve stem and valve guide.