In an internal combustion engine, the cylinder head sits above the cylinders and forms the roof of the combustion chamber. In sidevalve engines, the head is a simple sheet of metal; whereas in more modern overhead valve and overhead camshaft engines, the cylinder head is a more complicated block often containing inlet and exhaust passages, coolant passages, valves, camshafts, spark plugs and fuel injectors. Most straight engines have a single cylinder head shared by all of the cylinders and most V engines have two cylinder heads.
Engine tuning is the adjustment or modification of the internal combustion engine or Engine Control Unit (ECU) to yield optimal performance and increase the engine's power output, economy, or durability. These goals may be mutually exclusive; an engine may be de-tuned with respect to output power in exchange for better economy or longer engine life due to lessened stress on engine components.
A hemispherical combustion chamber is a type of combustion chamber in a reciprocating internal combustion engine with a domed cylinder head notionally in the approximate shape of a hemisphere. An engine featuring this type of hemispherical chamber is known as a hemi engine.
The Ford CVH engine is a straight-four automobile engine produced by the Ford Motor Company. The engine's name is an acronym for either Compound Valve-angle Hemispherical or Canted Valve Hemispherical, where "Hemispherical" describes the shape of the combustion chamber. The CVH was introduced in 1980 in the third generation European Escort and in 1981 in the first generation North American Escort. Engines for North America were built in Ford's Dearborn Engine plant, while engines for Europe and the UK were built in Ford's then-new Bridgend Engine plant in Wales.
The Ford 335 engine family was a group of engines built by the Ford Motor Company between 1969 and 1982. The "335" designation reflected Ford management's decision to produce an engine of that size with room for expansion during its development. This engine family began production in late 1969 with a 351 cu in (5.8 L) engine, commonly called the 351C. It later expanded to include a 400 cu in (6.6 L) engine which used a taller version of the engine block, commonly referred to as a tall deck engine block, a 351 cu in (5.8 L) tall deck variant, called the 351M, and a 302 cu in (4.9 L) engine which was exclusive to Australia.
VTEC is a system developed by Honda to improve the volumetric efficiency of a four-stroke internal combustion engine, resulting in higher performance at high RPM, and lower fuel consumption at low RPM. The VTEC system uses two camshaft profiles and hydraulically selects between profiles. It was invented by Honda engineer Ikuo Kajitani. It is distinctly different from standard VVT systems which change only the valve timings and do not change the camshaft profile or valve lift in any way.
Variable valve timing (VVT) is the process of altering the timing of a valve lift event in an internal combustion engine, and is often used to improve performance, fuel economy or emissions. It is increasingly being used in combination with variable valve lift systems. There are many ways in which this can be achieved, ranging from mechanical devices to electro-hydraulic and camless systems. Increasingly strict emissions regulations are causing many automotive manufacturers to use VVT systems.
VVT-i, or Variable Valve Timing with intelligence, is an automobile variable valve timing technology developed by Toyota. It was introduced in 1995 with the 2JZ-GE engine found in the JZS155 Toyota Crown and Crown Majesta.
The LA engines are a family of pushrod OHV small-block 90° V-configured gasoline engines built by Chrysler Corporation. They were factory-installed in passenger vehicles, trucks and vans, commercial vehicles, marine and industrial applications from 1964 through 2003. Their combustion chambers are wedge-shaped, rather than polyspherical, as in the predecessor A engine, or hemispherical in the Hemi. LA engines have the same 4.46 in (113 mm) bore spacing as the A engines.
The Ford Modular engine is Ford Motor Company's overhead camshaft (OHC) V8 and V10 gasoline-powered small block engine family. Introduced in 1990, the engine family received its “modular” designation by Ford for its new approach to the setup of tooling and casting stations in the Windsor and Romeo engine manufacturing plants.
An overhead camshaft (OHC) engine is a piston engine in which the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion chamber in the engine block.
An overhead valve (OHV) engine, sometimes called a pushrod engine, is a piston engine whose valves are located in the cylinder head above the combustion chamber. This contrasts with flathead engines, where the valves were located below the combustion chamber in the engine block.
The Ford Motor Company produced straight-six engines from 1906 until 1908 and from 1941 until 2016. In 1906, the first Ford straight-six was introduced in the Model K. The next was introduced in the 1941 Ford. Ford continued producing straight-six engines for use in its North American vehicles until 1996, when they were discontinued in favor of more compact V6 designs.
A flathead engine, also known as a sidevalve engine or valve-in-block engine, is an internal combustion engine with its poppet valves contained within the engine block, instead of in the cylinder head, as in an overhead valve engine.
A tappet is a valve train component which converts rotating motion into linear motion in activating a valve. It is most commonly found in internal combustion engines, which converts the rotating motion of the camshaft into linear motion of intake and exhaust valves, either directly or indirectly.
A valvetrain or valve train is a mechanical system that controls the operation of the intake and exhaust valves in an internal combustion engine. The intake valves control the flow of air/fuel mixture into the combustion chamber, while the exhaust valves control the flow of spent exhaust gasses out of the combustion chamber once combustion is completed.
In engine technology, a reverse-flow or non-crossflow cylinder head is one that locates the intake and exhaust ports on the same side of the engine. The gases can be thought to enter the cylinder head and then change direction to exit the head. This is in contrast to the crossflow cylinder head design.
The intake/inlet over exhaust, or "IOE" engine, known in the US as F-head, is a four-stroke internal combustion engine whose valvetrain comprises OHV inlet valves within the cylinder head and exhaust side-valves within the engine block.
Scavenging is the process of replacing the exhaust gas in a cylinder of an internal combustion engine with the fresh air/fuel mixture for the next cycle. If scavenging is incomplete, the remaining exhaust gases can cause improper combustion for the next cycle, leading to reduced power output.
Crossflow cylinder head, with twin overhead cams
Cutaway view of the overhead camshaft, rockers and valves of a crossflow cylinder head
Cross-section of a four-stroke engine showing the flow of gases across the cylinder head from the inlet port on the right to the exhaust port on the left, via the combustion chamber
