DICTIONARY OF AUTOMOTIVE TERMS - "Dy"

Dykem-type metal bluing

A special blue dye used to check a valve job. When applied to the valve set to show up as a dark ring contrasted against the brightly finished top and bottom cuts, making the seat easier to see and measure

Dykes ring

Dykes ring

A Compression piston ring which is L-shaped when viewed from the end. When installed in the Piston the horizontal part fits more deeply in the Piston groove while the vertical side rubs against the Cylinder wall. This style of ring gives good sealing and prevents piston-ring Flutter during Acceleration and Deceleration of the piston.

Dynamic balance

When the center line of the weight mass of a revolving object is in the same plane as the center line of the object, that object would be in dynamic balance. For example, the weight mass of the tire must be in the same plane as the center line of the wheel. Static balance is made off the vehicle and determined with the tire stationary. Dynamic balance is made with the tire in rotation.

Dynamic ignition timing

Before the introduction of a strobe light, ignition timing was done statically in that the distributor was moved a certain measured amount. With modern engines, a timing light or strobe light is used. It is connected, generally, with the spark plug of the number one cylinder. As power is provided to that cylinder from the coil, the timing light flashes. When the light is projected to the flywheel, the timing marks are illuminated. Moving the distributor will make the timing mark move closer to a fixed mark (retarded) or further away (advanced). Also called Stroboscopic ignition timing. The opposite is Static ignition timing

Dynamic imbalance

Lack of balance in a rotating part such as a wheel, which can cause vibration and shudder

Dynamic unbalance

A noise-producing condition in an electric motor caused by the nonsymmetrical weight distribution of a rotating member. The lack of a uniform wire spacing in a wound armature or casting voids in a rotor or fan assembly can cause relatively high degrees of unbalance

Dynamic seal

Oil seal between a moving and a stationary part. Opposite to Static seal

Dynamic supercharging

The pressurizing of the air/fuel mixture using the natural dynamic behaviour of the aspirated air, and not some mechanical device to compress it

Dynamic timing meter

A GM diesel tool used for measuring timing while the engine is running by using a quartz sensor in the combustion chamber that measures the point of combustion and converts this to timing in degrees of crankshaft flotation through the use of a magnetic crankshaft pickup and microprocessor

Dynamo

A British term for a Generator producing direct current.

Also See
Alternator

Dynamometer

1. An electric or hydraulic machine used to measure the actual engine Horsepower output and Torque. An engine dynamometer measures horsepower at the Crankshaft and a Chassis dynamometer measures horsepower output at the wheels.
2. Device for measuring power output or power input of a mechanism.

Also See
Absorption dynamometer
Roller dynamometer

Dynastart

A combined generator and starter used on some cars in the 1920s and '30s, and more recently on two-stroke motorcycles

Dynastarter

A combined generator and starter used on some cars in the 1920s and '30s, and more recently on two-stroke motorcycles

Dyne

A metric unit of force. 1 dyne of force is applied when a 1 gram object is accelerated 1 cm/s².