Glossary “bowl vent port” Definition:
Port in a carburetor which vents vapors and excess pressure from the bowl to maintain atmospheric pressure.
b
box end wrench
Glossary “box end wrench” Definition:
Wrench with closed ends that surround the bolt or nut head.
boundary layer
Glossary “boundary layer” Definition:
The thin layer of air along the inner walls of an intake port.
boundary lubrication
Glossary “boundary lubrication” Definition:
When an oil film becomes too thin or starts to break down under load.
Bourdon tube
Glossary “Bourdon tube” Definition:
A curved tube that straightens as the pressure inside it is increased. The tube is attached to a needle on a gauge, that senses the movement of the tube and transmits it as a pressure reading.
Bowden cable
Glossary “Bowden cable” Definition:
1). A wire cable inside a metal or rubber housing used to regulate a valve or control it from a remote place. 2). A small steel cable inside a flexible tube used to transmit mechanical motion from one point to another.
bottom U-bolt plate
Glossary “bottom U-bolt plate” Definition:
A plate that is located on the bottom side of the spring or axle and is held in place when the U-bolts are tightened.
bottom valve
Glossary “bottom valve” Definition:
A shock absorber component to control the flow of oil into the reservoir during compression and rebound.
bounce back
Glossary “bounce back” Definition:
A condition that occurs when particles of paint sprayed on a body panel bounce away from the surface.
bound
Glossary “bound” Definition:
The opposite of rebound. The inward travel of the piston rod in a shock absorber.
bound electron
Glossary “bound electron” Definition:
An electron whose orbit is near the nucleus of an atom and is strongly attracted to it.
bottom out
Glossary “bottom out” Definition:
Suspension has traveled beyond its limits.
bored and stroked
Glossary “bored and stroked” Definition:
A combination of an enlarged cylinder bore and a lengthened piston stroke to increase an engine’s displacement.
boring
Glossary “boring” Definition:
Process by which a machinist enlarges a hole or cylinder.
boss
Glossary “boss” Definition:
The reinforced extension on a part that holds a mounting pin, bolt, or stud.
bottom
Glossary “bottom” Definition:
1. The underside; the lowest part. 2. When a vehicle’s chassis hits the lowest point allowed by its suspension system. 3. When the springs are fully compressed.
bottom dead center (BDC)
Glossary “bottom dead center (BDC)” Definition:
Piston position at bottom of stoke.
bottom end
Glossary “bottom end” Definition:
The crankshaft main bearing and connecting-rod bearing assembly in an engine.
bore
Glossary “bore” Definition:
1). The diameter of an engine cylinder. 2). To increase the diameter of a cylinder.
bore align
Glossary “bore align” Definition:
To machine an engine’s main bearing journals to assure they are in perfect alignment.