ASVAB Automotive Information Practice Test 157997

Questions 5
Topics Ignition Timing, Spark Plugs, Thermostat, Universal Joints, Water Pump

Study Guide

Ignition Timing

Ignition timing defines the point in time at the end of the compression stroke that the spark plug fires. Measured in number of degrees before top dead center (BTDC), the exact point that the spark plugs initiate combustion varies depending on the speed of the engine. The timing is advanced (the spark plugs fire a few more degrees BTDC) when the engine is running faster and retarded when it's running slower.

Spark Plugs

Spark plugs receive current from the distributor and use it to spark combustion in the combustion chamber of a cylinder.

Thermostat

The thermostat controls coolant (and, through it, engine) temperature by regulating the flow of coolant through the radiator. A bypass tube allows coolant to bypass the radiator and flow back into the water pump when its temperature is low enough that the thermostat is closed.

Universal Joints

Like CV joints, universal joints (U-joints) are located at each end of a drive shaft and allow the shaft to operate at a variable angle with the item it is driving. Universal joints perform the same basic function as CV joints but CV joints have a wider range of operation.

Water Pump

The water pump is driven by a belt connected to the crankshaft and ensures that coolant moves through the engine and radiator.