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Casting Flash

A thin metal exuding at the parting edges of a casting mold, evident when the part is removed from the mold.

Casting Number

A part number that has been cast into a part during manufacture.

Castor Oil

A lubricant made from the castor bean.

Cat

An abbreviation for catalytic converter.

Cat-back Exhaust System

A replacement (usually high-performance) exhaust system that starts behind a vehicle's catalytic converter or converters. The cat-back system includes piping, one or two mufflers and one or two tailpipes. It usually provides a freer flow than the system it replaces, so it reduces backpressure and improves the vehicle's performance. Most high-performance exhaust systems for new vehicles are cat-back systems, because it is illegal to remove or replace a catalytic converter that is functioning properly, if the vehicle will be driven on public roads. Many high-performance exhaust systems can be ordered with a high-temperature coating.

Catalog

An illustrated or ordered list of items and descriptions with sufficient data to identify the item.

Catalysis

The action of a catalyst.

Catalyst

A lead-sensitive substance, such as platinum, palladium, or rhodium, that accelerates or enhances a chemical reaction without being changed itself. When used in a catalytic converter, it can reduce the level of harmful pollutants in the exhaust.

Catalyst Poisoning

The process of specific impurities binding to a catalyst.

Catalytic

An action involving a catalyst

Catalytic Converter

An automotive exhaust-system component, made of stainless steel, containing a catalyst to reduce oxides of nitrogen (Nox), and/or hydrocarbon (HC), and carbon monoxide (CO), in tailpipe emissions.

Catch Can

A container on a race car's radiator or fuel tank to prevent liquid from spilling on the ground during a pit stop.

Catch Tank

A term often used for catch can.

Catenary Effect

The curve that a length of chain assumes between its suspension points.

Cathode

[1] The negatively charged cell from which current flows in an electrolytic cell. [2] The negative electrode of a semiconductor diode [3] The portion of a fuel cell where Oxygen "reduction" occurs.

Cathode Ray Tube (CRT)

A vacuum tube used in electronic equipment and some electronic readouts to display information.

Cation

A positive ion. Phosphoric acid and PEM fuel cells are "cation-mobile" cells.

Caulking Compound

A thick, viscous material used as a sealer at joints, such as around the windshield.

Caustic

1. A salt-based chemical for cleaning engine parts. 2. A cleaner that may be used for most metals, except aluminum.

Caution Flag

A yellow flag displayed to race-car drivers to indicate a slow down. Also used to indicate no passing, due to a problem or mishap on the race track.