The roof support between a vehicle's front door window and rear side window, if there is one.

The sudden combustion of gases in the intake or exhaust system that results in a loud explosion.

The clearance or play between two parts, such as meshed gears.

Restrictions in the exhaust system that slow the exit of exhaust gases from the combustion chamber.

A heat resistant, plastic insulator material commonly used in printed circuit boards and transistorized components.

A shaft designed so that, as it rotates, it vibrates in a way that reduces or cancels some of the vibration produced by an engine. Not essential to an engine's operation, balance shafts are nonetheless becoming increasingly common as a means of engine refinement. Balance-shafted four-cylinder engines use two shafts turning in opposite directions on either side of the engine's crankshaft. A single balance shaft is used when fitted to three-cylinder and V-6 engines.

The process of making sure a tire will not cause vibration when driving. By using a computerized machine, a technician can locate a non-balanced tire and balance it by attaching weights on the wheel rim to even out the tire's balance.

A bearing made up of hardened inner and outer races between which hardened steel balls roll.

A flexible joint consisting of a ball in a socket, used primarily in front suspensions because it can accommodate a wide range of angular motion. The ball joint allows the wheel to steer and move with the suspension and still receive power from the engine. The term ball joint can also be used to refer to how suspension components are attached.

A resister in the primary ignition circuit that lowers voltage after the engine is started to reduce wear on ignition components.

A barrel is a venturi in a carburetor where air and fuel are mixed, then taken into the intake manifold and then to a cylinder. Carburetors usually have from one to four barrels, depending on the engine application. '2bbl' means that the carburetor has 2 barrels or venturi (or fuel nozzles). A '4bbl' carburetor has 4 barrels, etc. The number of venturi determine the amount of fuel that the carburetor can supply. A 4bbl. carburetor can usually provide more fuel than a similar 2bbl. unit.

A paint system that adds a final clear-coat paint layer over primer and color coats to provide a deep, 'wet-look' shine that resists fading.

Car batteries store and supply electrical current to a vehicle's starting, ignition, and electrical systems.

A rigid axle supporting the non-driven wheels. Also called a dead axle.

Bearings are used to prevent wear when two moving parts are placed very close to each other.

A system where the final drive from gearbox to wheels is by leather or rubber belts that are contained on pulleys. Today many of the engine-driven auxiliaries use belt drives.

A reinforcing bank, normally textile, fiberglass or steel, running around the circumference of a tire and strengthening the tread area.

The line running around a car's body formed by the bottom edges of its glass panels.

Belts are used to drive many engine accessories. Most overhead cam(OHC) engines use cogged (toothed) belts to drive the camshaft(s). Belts drive the power steering pump, water pump, air-conditioning compressors, etc.

From World War I, it described a closed luxury car with small windows, which allowed the occupants to see out but to be barely seen from the outside.