Glossary “joint fit up” Definition:
Refers to holding work pieces tightly together, in alignment, to prepare for welding. It is critical to the replacement of body parts.
j
joint penetration
Glossary “joint penetration” Definition:
Depth a filler metal extends from its face into a joint, exclusive of weld reinforcement.
joule(J)
Glossary “joule(J)” Definition:
A unit of energy, measured in newtons per meter. The rate of using joules per second is watts.
jounce
Glossary “jounce” Definition:
The inward reaction of the spring and shock absorber when a wheel hits an obstruction.
JMS
Glossary “JMS” Definition:
Jet Mixture Solenoid
Johnson rod
Glossary “Johnson rod” Definition:
A mythical automotive component that is blamed for any problem that cannot otherwise be explained.
joint
Glossary “joint” Definition:
Junction of members that are to be joined or have been joined.
JFET
Glossary “JFET” Definition:
Junction Field Effect Transistor: Field effect transistor formed by combining layers of semiconductor material. The JFET has an input impedance equal to the reverse bias impedance of a p-n junction. This impedance is approximately 20,000 M ohms.
jig
Glossary “jig” Definition:
1). Fixture for holding work. 2). Device used as an aid to straighten the frame of a vehicle.
JIS
Glossary “JIS” Definition:
Japanese Industrial Standard.
jet
Glossary “jet” Definition:
Calibrated passage in the carburetor used to meter fuel flow. A metered orifice in a carburetor which meters fuel flow. Larger jets allow more fuel to flow than smaller jets. Jets are usually replaceable and available in different sizes.
jet car
Glossary “jet car” Definition:
Race car powered by a jet aircraft engine.
jet valve
Glossary “jet valve” Definition:
An intake valve, located in a precombustion chamber, that admits a highly concentrated air/fuel mixture into a stratified charge engine.
Jeep
Glossary “Jeep” Definition:
Just Empty Every Pocket, or Just Eats Every Part
jerk
Glossary “jerk” Definition:
Sudden lurch occurs due to power flow interruption during acceleration.
Japanese Industrial Standards (JIS)
Glossary “Japanese Industrial Standards (JIS)” Definition:
Japan’s equivalent of the DIN in Germany or the SAE in the United States.
J/B
Glossary “J/B” Definition:
Junction Block
jackshaft
Glossary “jackshaft” Definition:
Shaft found in most overhead cam engines that can be used to drive the distributor, fuel pump, and oil pump.
Jacobs brake
Glossary “Jacobs brake” Definition:
Device more commonly known as Jake brake.
Jacob's ladder
Glossary “Jacob’s ladder” Definition:
1). Triangular control linkage to center the rear axle assembly, found on some rear-wheel-drive race cars. 2). High voltage discharge device.