The knock sensor is an essential component of the engine management system, there to detect and manage spark knock. Spark knock is what happens when an air/fuel mixture ignites too early, or if the fuel is too low octane (which allows it to burn too quickly), or if the combustion is uneven leading to colliding … Read more
Every gas engine uses spark plugs to fire the air-fuel mixture, as the end-point in the ignition system. A spark plug screws into the cylinder head on each cylinder, and has a pair of contacts on it’s end. The ignition system coil sends a high voltage spark across the contacts at the appropriate time, which … Read more
A universal joint or u-joint is a cross-shaped casting with short even-length arms, and cups with needle bearings fitted onto the end of each arm. It is packed with heavy grease for lubrication and often has a grease fitting to allow regular servicing. The bearing cups press into machined holes in the driveshaft and component … Read more
An idler pulley is basically a pulley housing with an integral sealed bearing pressed in. The purpose of the idler pulley is to facilitate the serpentine belt routing – either to route it around an engine obstruction or to wrap the belt around an accessory pulley more fully in a way that improves its bearing … Read more
The function of a serpentine belt is very simple: it transmits engine power from the crankshaft to the driven accessories. Typically, those would be the water pump, the alternator, the AC compressor, and the power steering pump. Some engines have fewer things while others (such as diesel engines) have more. The serpentine belt is held … Read more
Most bearing failures are the result of simple wear. Ideally, if the manufacturing tolerances were good and the seals effective, wear is minimal and very slow. Excess wear on the bearings can occur if a vehicle is overloaded; causing the bearings to run hot and break down their lubricant – leading to more rapid wear. … Read more
A starter is essentially a strong electric motor that spins up the engine of a vehicle; allowing it to start its fuel-powered operation. It draws a great deal of current from the battery to turn the engine. As with any high-current electrical device, reliable switching of power is difficult. Starter motors almost always have an … Read more
All modern automobile engines are “water-cooled” which means they use circulating fluid to carry heat from the engine to a radiator where it is cooled and circulated back. Coolant is about 50% water and the balance is made up of a variety of chemicals and additives. These lower the freezing point, improve the heat absorption … Read more
On any automobile engine, one of the basic engineering challenges is how to transfer the rotating force from the crankshaft to the valve train. This is so that the valves open and close at exactly the correct times relative to the motion of the pistons. On most older-style engines, this is done by a camshaft … Read more
Some engines rely on a single chain to operate overhead cams, some rely on two or three chains, and some have more than that. In any case, all are directly timed to the crankshaft. There is a fixed order to disassembly and reassembly, and there are marks to get everything set up correctly. In order … Read more