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Duplex

Simultaneous, independent, two-way transmission in both directions.

Dura Spark Ignition

An ignition system developed by Ford.

Durability

The quality of being useful, generally referring to the life of a catalyst or emission-control system.

Duration

1.The time, in crankshaft degrees, that a camshaft holds an exhaust or intake valve open. 2. A rating system applied to engine camshafts that determines how long the valve will be open relative to crankshaft movement in degrees.

Dust

To overtake or defeat a competitor in a race.

Dust Off

A term often used for dust.

Dust Shield

1. The upper portion of a shock absorber that surrounds the lower twin-tube unit. 2. A covering that protects an assembly from the elements.

Dutched

A paint job finished with elaborate striping or flame painting.

Duty Cycle

1. The percentage of time a component is on compared to the time the component is off during one cycle. 2.The percentage of time that a power source, or one of its accessories, can be operated at rated output, without overheating.

Duty Solenoid

A solenoid on a feedback carburetor that cycles many times per second to control a metering rod, and therefore, the air/fuel mixture.

DV

Diverter valve or delay valve.

DV-TW

Delay valve-two way.

DV/TS

Delay valve/trapped spark.

DVA

Distributor vacuum advance.

DVAC

Distributor vacuum advance control.

DVAS

Distributor vacuum advance solenoid.

DVC

Distributor vacuum control.

DVCD

Distributor vacuum delay valve.

DVCS

Distributor vacuum control solenoid.

DVCV

Distributor vacuum control valve.