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Overlubrication

Term referring to the application of lubricant amounts in excess of factory recommendations that my overload or damage grease seals.

Overpull

The pulling of a body member beyond its specifications with the expectation that it will snap back to its intended shape when the pulling effort is discontinued.

Overrev

To run an engine at excessive rpm.

Overrunning Clutch

A device used when two members are to run freely relative to each other in one direction, but are to lock in the other direction.

Overrunning-clutch Drive

An overrunning clutch used for the engagement and disengagement of a starting motor.

Oversize (OS)

A part that is larger than the original to make up for wear and matching.

Oversize Valve Stem

A valve having a stem diameter that is larger than the stem diameter of the original valve. It is used to fit a worn valve guide that is reamed oversize.

Overspray

1. A paint spray mist that drifts onto a surface where it is not wanted. 2. The overlap of new paint over old paint.

Oversquare

A cylinder with a bore greater than its stroke.

Overstaging

Staging a drag racer ahead of the usual staging position.

Oversteer

A condition in cornering when the rear wheels of a race car tend to break loose and slide outward.

Overvoltage Protection Relay

An electrical device used in ABSs that prevents damage to electronic components and circuits due to electrical surges or spikes.

OVPR

The overvoltage protection relay is an electrical device used in ABSs that prevents damage to electronic components and circuits due to electrical surges or spikes.

Oxidation

1. The process in which one element of a compound is combined with oxygen in a chemical process that produces another compound. 2. The combination of a substance with oxygen forming an oxide, such as rust.

Oxidation Catalyst

A two-way catalytic converter which promotes the oxidation of HC and CO in an engine's exhaust stream, as distinguished from a three-way or reduction catalyst.

Oxidation Inhibitor

An additive to reduce the chemicals in gasoline that react to oxygen.

Oxide

A compound formed when a substance combines with oxygen.

Oxides Of Nitrogen (NOx)

Harmful, gaseous emissions of an engine composed of compounds of nitrogen and varying amounts of oxygen which are formed at the highest temperatures of combustion.

Oxidize

To form an oxide.

Oxidizer

1. A material that caused oxidation. 2. An additive that increases the oxygen content of an air/fuel mixture.