Glossary “valve port” Definition:
Passage that allows the flow of intake or exhaust, into or out of the cylinder.

Glossary “valve position sensor” Definition:
Sensor that relays information, in electronic form, to a process relative to the position of a valve.

Glossary “valve lifter” Definition:
Cylindrically shaped hydraulic or mechanical device in the valve train that rides on the camshaft lobe to lift the valve off its seat by following the contoiur of the cam lobe(s).

Glossary “valve lifter foot” Definition:
End of a valve lifter that rides on the camshaft.

Glossary “valve margin” Definition:
A small margin around the edge of the valve head between the valve head and the valve face. The margin adds strength and heat resistance to the valve.

Glossary “valve overlap” Definition:
The time that the closing of the exhaust valve overlaps the opening of the intake valve at the end of the exhaust stroke and at the beginning of the intake stroke, when the intake and exhaust valves are partially open at the same time depending on the spacing of the lobe centers on the camshaft and the cam’s duration.

Glossary “valve lift” Definition:
Distance that the valve moves from the closed to the open position.

Glossary “valve keeper” Definition:
Small part that fits into the retainer groove located near the tip of the valve stem to secure the valve and valve spring.

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

Glossary “valve lash” Definition:
Specified clearance between a valve stem end and a rocker arm on an OHV engine or valve stem end and the camshaft on an OHC engine; necessary to allow for heat expansion.

Glossary “valve guide” Definition:
Bore in the cylinder head through which the valve stem passes.

Glossary “valve head” Definition:
Term designating the enlarged end of the valve.

Glossary “valve job” Definition:
Reconditioning of a cylinder head, including the valves.

Glossary “valve face” Definition:
Tapered section of the valve head making contact with the valve seat.

Glossary “valve float” Definition:
1). Valve that does not close completely. 2). Valve that does not close at the proper time, due to high engine RPM.

Glossary “valve clearance” Definition:
Term used for valve lash. Usually adjustable clearance in the valve train.

Glossary “valve curtain” Definition:
Opening of the annular passage between the valve and its seat when the valve is fully open.

Glossary “valve duration” Definition:
Length of time that a valve is open, measured in degrees of crankshaft rotation.

Glossary “valve arrangement” Definition:
The way valves are placed in an engine, such as valves-in-head or valves-in-block.