Engine tuning

Engine tuning

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Engine tuning is the adjustment, modification or design of internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

s to yield optimal performance, to increase an engine's power output, economy, or durability.

It has a long history, almost as long as the development of the car
An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...

 in general, originating with the development of early racing cars, and later, with the post-war hot-rod movement. Tuning can describe a wide variety of adjustments and modifications, from the routine adjustment of the carburetor
A carburetor , carburettor, or carburetter is a device that blends air and fuel for an internal combustion engine. It is sometimes shortened to carb in North America and the United Kingdom....

 and ignition system
Ignition system
An ignition system is a system for igniting a fuel-air mixture. Ignition systems are well known in the field of internal combustion engines such as those used in petrol engines used to power the majority of motor vehicles, but they are also used in many other applications such as in oil-fired and...

 to significant engine overhauls. At the other end of the scale, performance tuning of an engine can involve revisiting some of the design decisions taken at quite an early stage in the development of the engine.

Setting the idle speed, fuel/air mixture, carburetor balance, spark plug and distributor point gaps, and ignition timing were regular maintenance items for all older engines and the final but essential steps in setting up a racing engine. On modern engines, equipped with electronic ignition and fuel injection, some or all of these tasks are automated, although they still require periodic calibration.

Engine tune-up

A tune-up usually refers to the routine servicing of the engine to meet the manufacturer's specifications. Tune-ups are needed periodically as according to the manufacturer's recommendations to ensure an automobile runs as expected. Modern vehicles now typically require only a few tune-ups over the course of an approximate 250000 kilometres (155,343.2 mi) or a 10-year lifespan.

Tune-ups may include the following:
  • Re-fastening of cylinder head
    Cylinder head
    In an internal combustion engine, the cylinder head sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder, forming the combustion chamber. This joint is sealed by a head gasket...

  • Adjustment of the carburetor idle speed and the air-fuel mixture
  • Inspection and possible replacement of ignition system components like spark plugs, contact breaker
    Contact breaker
    A contact breaker is a type of electrical switch, and the term typically refers to the switching device found in the distributor of the ignition systems of spark-ignition internal combustion engines.-Purpose:...

     points, distributor
    A distributor is a device in the ignition system of an internal combustion engine that routes high voltage from the ignition coil to the spark plugs in the correct firing order. The first reliable battery operated ignition was developed by Dayton Engineering Laboratories Co. and introduced in the...

     cap and distributor rotor
  • Replacement of the air filter
    Air filter
    A particulate air filter is a device composed of fibrous materials which removes solid particulates such as dust, pollen, mold, and bacteria from the air. A chemical air filter consists of an absorbent or catalyst for the removal of airborne molecular contaminants such as volatile organic compounds...

     and other filters
  • Inspection of emission controls
  • Valvetrain
    Poppet valve
    A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide...


In early days, mechanics finished tuning up a performance car such as a Ferrari and would take it around a track several times to burn out any built-up carbon; this is known as an Italian tuneup
Italian tuneup
An Italian tuneup usually refers to a process whereby the operator of a motor vehicle runs the engine at full load for extended periods in order to burn carbon buildup from the combustion chambers and exhaust system. It is performed after a traditional tuneup and often accompanied by an addition of...


Chip tuning

Modern engines are equipped with an engine management system
Electronic control unit
In automotive electronics, electronic control unit is a generic term for any embedded system that controls one or more of the electrical systems or subsystems in a motor vehicle....

 (EMS) which can be modified to different settings, producing different performance levels. Manufacturers often produce a few engines which are used in a wider range of models and platforms, and this allows the manufacturers to sell cars in various markets with different regulations without having to spend money developing and designing different engines to fit these regulations. This also allows for a single engine to be used by different brands, tuned to suit their particular market..

Performance tuning

Performance tuning focuses on tuning an engine for motorsport
Motorsport or motorsports is the group of sports which primarily involve the use of motorized vehicles, whether for racing or non-racing competition...

, although many such cars never compete but rather are built for show or leisure driving. In this context, the power output, torque, and responsiveness of the engine are of premium importance, but reliability and fuel economy are also relevant. In races, the engine must be strong enough to withstand the additional stress placed upon it, and so is often far stronger than any mass-produced design on which it may be based, and also that the vehicle must carry sufficient fuel. In particular, the transmission
Transmission (mechanics)
A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...

, driveshaft
A drive shaft, driveshaft, driving shaft, propeller shaft, or Cardan shaft is a mechanical component for transmitting torque and rotation, usually used to connect other components of a drive train that cannot be connected directly because of distance or the need to allow for relative movement...

 and any other load-transmitting powertrain
In a motor vehicle, the term powertrain or powerplant refers to the group of components that generate power and deliver it to the road surface, water, or air. This includes the engine, transmission, drive shafts, differentials, and the final drive...

 components may need to be modified in order to withstand the load from the increased power.

In most cases, people are interested in increasing the power output of an engine. Many well tried and tested techniques have been devised to achieve this, but all essentially operate to increase the rate (and to a lesser extent efficiency) of combustion in a given engine. This is achieved by putting more air/fuel mixture into the engine, increasing compression ratio
Compression ratio
The 'compression ratio' of an internal-combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity...

 (requires higher octane gas) burning it more rapidly, and getting rid of the waste products more rapidly - this increases volumetric efficiency
Volumetric efficiency
Volumetric efficiency in internal combustion engine design refers to the efficiency with which the engine can move the charge into and out of the cylinders. More specifically, volumetric efficiency is a ratio of what quantity of fuel and air actually enters the cylinder during induction to the...

. In order to check the amount of the air/fuel mixture, air fuel ratio meters are often used. The weight of this fuel will affect the overall performance of the car, so fuel economy is a competitive advantage. This also means that the performance tuning of an engine should take place in the context of the development of the overall vehicle.

The specific ways to increase power include:
  • Increasing the engine displacement
    Engine displacement
    Engine displacement is the volume swept by all the pistons inside the cylinders of an internal combustion engine in a single movement from top dead centre to bottom dead centre . It is commonly specified in cubic centimeters , litres , or cubic inches...

     by one or both of two methods: "boring" - increasing the diameter of the cylinder
    Cylinder (engine)
    A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...

    s and piston
    A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from...

    s, or by "stroking
    Stroker Kit
    A Stroker kit is an aftermarket assembly that increases the displacement of a reciprocating engine by increasing the travel of the piston . This is done by using a different crankshaft where the crank pin is moved further away from the center of the axis of rotation of the crankshaft...

    " - using a crankshaft
    The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...

     with a greater throw.
  • Using larger or multiple carburetors, to create a more controllable air/fuel mixture to burn, and to get it into the engine more smoothly. In modern engines, fuel injection
    Fuel injection
    Fuel injection is a system for admitting fuel into an internal combustion engine. It has become the primary fuel delivery system used in automotive petrol engines, having almost completely replaced carburetors in the late 1980s....

     is more often used, and may be modified in a similar manner.
  • Increasing the size of the valves
    Poppet valve
    A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide...

     in the engine, thus decreasing the restriction in the path of the fuel–air mixture entering, and the exhaust gases leaving the cylinder. Using multiple valves
    In automotive engineering a multi-valve or multivalve engine is one where each cylinder has more than two valves. A multi-valve engine has better breathing and can operate at higher revolutions per minute than a two-valve engine, delivering more power.- Multi-valve rationale :A multi-valve design...

     per cylinder results in the same effect – it is often more difficult to fit several small valves than to have larger single valves due to the valve gear required. However it is difficult to find space for one large valve in the inlet and a large valve on the outlet side. Sometimes a large exhaust valve and two smaller inlet valves are fitted for improved flow. As the pressure generated during combustion provides more force to exhaust the waste gasses than the force available to inlet clean charged gas, a larger inlet valve area is needed to provide easier flow. The two smaller inlet valves' total area is larger than that of the single exhaust valve and thus provides that easier inlet flow. This is why exhaust valves are typically smaller in area than the inlet valves.
  • Using larger bored, smoother, less contorted intake
    Inlet manifold
    In automotive engineering, an inlet manifold or intake manifold is the part of an engine that supplies the fuel/air mixture to the cylinders...

     and exhaust manifold
    Exhaust manifold
    In automotive engineering, an exhaust manifold collects the exhaust gases from multiple cylinders into one pipe. The word manifold comes from the Old English word manigfeald and refers to the folding together of multiple inputs and outputs.In contrast, an inlet manifold is the part of an engine...

    s. This helps maintain the velocity of gases. Similarly, the ports in the cylinder head can be enlarged and smoothed to match. This is termed cylinder head porting
    Cylinder head porting
    Cylinder head porting refers to the process of modifying the intake and exhaust ports of an internal combustion engine to improve the quality and quantity of the air flow. Cylinder heads, as manufactured, are usually suboptimal due to design and manufacturing constraints...

    , usually with the aid of an air flow bench
    Air flow bench
    An air flow bench is a device used for testing the internal aerodynamic qualities of an engine component and is related to the more familiar wind tunnel.Used primarily for testing the intake and exhaust ports of cylinder heads of internal combustion engines...

     for testing and verifying the efficiency of the modifications. Manifolds with sharp turns force the air–fuel mix to separate at high velocities as fuel is heavier than air.
  • The larger bore may extend right through the complete exhaust system
    Exhaust system
    An exhaust system is usually tubing used to guide reaction exhaust gases away from a controlled combustion inside an engine or stove. The entire system conveys burnt gases from the engine and includes one or more exhaust pipes...

    , using larger diameter piping and low back pressure
    Back pressure
    Back pressure refers to the resistance to a moving fluid by obstructions or tight bends in the confinement vessel along which it is moving, such as piping or air vents, against its direction of flow....

    A muffler is a device for reducing the amount of noise emitted by the exhaust of an internal combustion engine. A US Patent for an Exhaust muffler for engines was granted to Milton and Marshall Reeves in 1897....

    s, and through the intake system, with larger diameter airboxes and high-flow, high-efficiency air filter
    Air filter
    A particulate air filter is a device composed of fibrous materials which removes solid particulates such as dust, pollen, mold, and bacteria from the air. A chemical air filter consists of an absorbent or catalyst for the removal of airborne molecular contaminants such as volatile organic compounds...

    s. Muffler modifications will change the sound of the car's engine, usually making it louder; for some tuners this is in itself a desirable effect.
  • Increasing the valve opening height (lift), by changing the profiles of the cams on the camshaft
    A camshaft is a shaft to which a cam is fastened or of which a cam forms an integral part.-History:An early cam was built into Hellenistic water-driven automata from the 3rd century BC. The camshaft was later described in Iraq by Al-Jazari in 1206. He employed it as part of his automata,...

    , or the lift (lever
    In physics, a lever is a rigid object that is used with an appropriate fulcrum or pivot point to either multiply the mechanical force that can be applied to another object or resistance force , or multiply the distance and speed at which the opposite end of the rigid object travels.This leverage...

    ) ratio of the valve rockers (OHV
    Overhead valve
    An overhead valve engine, also informally called pushrod engine or I-head engine, is a type of piston engine that places the camshaft within the cylinder block , and uses pushrods or rods to actuate rocker arms above the cylinder...

     engines), or cam followers (OHC engines).
  • Optimizing the valve timing to improve burning efficiency - usually this increases power at one range of operating RPM at the expense of reducing it at others. For many applications this compromise is acceptable. This can usually be achieved by fitting a differently profiled camshaft. See also valve timing, variable valve timing
    Variable valve timing
    In internal combustion engines, variable valve timing , also known as Variable valve actuation , is a generalized term used to describe any mechanism or method that can alter the shape or timing of a valve lift event within an internal combustion engine...

  • Raising the compression ratio
    Compression ratio
    The 'compression ratio' of an internal-combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity...

     by reducing the size of the combustion chamber, which makes more efficient use of the cylinder pressure developed and leading to more rapid burning of fuel, by using larger compression height pistons or thinner head gasket
    Head gasket
    A head gasket is a gasket that sits between the engine block and cylinder head in an internal combustion engine. Its purpose is to seal the cylinders to ensure maximum compression and avoid leakage of coolant or engine oil into the cylinders; as such, it is the most critical sealing application in...

    s, or by milling
    Milling machine
    A milling machine is a machine tool used to machine solid materials. Milling machines are often classed in two basic forms, horizontal and vertical, which refers to the orientation of the main spindle. Both types range in size from small, bench-mounted devices to room-sized machines...

     or "shaving" the cylinder head
    Cylinder head
    In an internal combustion engine, the cylinder head sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder, forming the combustion chamber. This joint is sealed by a head gasket...

    . High compression ratios can cause engine knock unless high octane
    Octane is a hydrocarbon and an alkane with the chemical formula C8H18, and the condensed structural formula CH36CH3. Octane has many structural isomers that differ by the amount and location of branching in the carbon chain...

     fuels are used.
  • Forced Induction
    Forced induction
    Forced induction is the process of compressing air on the intake of an internal combustion engine . A forced induction engine uses a gas compressor to increase the pressure, temperature and density of the air...

    ; adding a turbocharger
    A turbocharger, or turbo , from the Greek "τύρβη" is a centrifugal compressor powered by a turbine that is driven by an engine's exhaust gases. Its benefit lies with the compressor increasing the mass of air entering the engine , thereby resulting in greater performance...

     or supercharger
    A supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...

    . The air/fuel mix entering the cylinders is increased by compressing the air. Further gains may be realized by cooling compressed (and thus heated) intake air with an air-to-air or air-to-water intercooler
    An intercooler , or charge air cooler, is an air-to-air or air-to-liquid heat exchange device used on turbocharged and supercharged internal combustion engines to improve their volumetric efficiency by increasing intake air charge density through nearly isobaric cooling, which removes...

  • Using a fuel with higher energy content and by adding an oxidizer such as nitrous oxide
    Nitrous oxide
    Nitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...

  • Reducing losses to friction
    Friction is the force resisting the relative motion of solid surfaces, fluid layers, and/or material elements sliding against each other. There are several types of friction:...

     by machining moving parts to lower tolerances than would be acceptable for production, or by replacing parts. A common example of this is, in OHV engines, replacing the production rocker arms with replacements incorporating roller bearings in the roller contacting the valve stem.
  • Reducing the "rotating mass", which comprises the crankshaft, connecting rods, pistons, and flywheel
    A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia, and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed...

    . Doing so can improve throttle response due to lower rotational inertia, as well as reduce overall vehicle weight. This may be achieved by using alloy
    An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...

     parts instead of steel. However a heavy crankshaft can void the need for a flywheel (common on V6 engines).
  • Changing the tuning characteristics electronically, by changing the firmware
    In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...

     of the EMS. This chip tuning
    Chip tuning
    Chip tuning refers to changing or modifying an EPROM chip in a car's or other vehicle's electronic control unit to achieve better performance, whether it be more power, cleaner emissions, or better fuel economy....

    often works because modern engines are designed to produce more power than required, which is then reduced by the EMS to make the engine operate smoothly over a wider RPM range, with low emissions. This is called de-tuning and produces long-lasting engines and the ability to increase power output later for facelift models. Recently emissions have played a large part in de-tuning, and engines will often be de-tuned to produce a particular carbon output for tax reasons.
  • Lowering the underbonnet temperature, which has the effect of lowering the engine intake temperature, therefore increasing the power. This is often done by installing a type of thermal insulation (normally a heatshield, thermal barrier coating or other type of exhaust heat management
    Exhaust heat management
    Exhaust Heat Management is the means of lessening the negative effects of internal combustion engine exhausts by preventing heat from escaping the exhaust system on automobiles.-Overview:...

    ) on or around the exhaust manifold
    Exhaust manifold
    In automotive engineering, an exhaust manifold collects the exhaust gases from multiple cylinders into one pipe. The word manifold comes from the Old English word manigfeald and refers to the folding together of multiple inputs and outputs.In contrast, an inlet manifold is the part of an engine...

    . This ensures that more heat is diverted out and away from the underbonnet area.

The choice of modification depends greatly on the degree of performance enhancement desired, budget, and the characteristics of the engine to be modified. Intake, exhaust, and chip upgrades are usually amongst the first modifications made as they are the cheapest, make reasonably general improvements, whereas a different camshaft, for instance, requires trading off smoothness at low engine speeds for improvements at high engine speeds.

Furthermore, tuners may also use analytical tools to help evaluate and predict the effect of modifications on the performance of the vehicle.


An overhauled engine is an engine which has been removed, disassembled (tear down), cleaned, inspected, repaired as necessary and tested using factory service manual approved procedures.
The procedure generally involves honing
Honing (metalworking)
Honing is an abrasive machining process that produces a precision surface on a metal workpiece by scrubbing an abrasive stone against it along a controlled path...

, new piston ring
Piston ring
A piston ring is a split ring that fits into a groove on the outer diameter of a piston in a reciprocating engine such as an internal combustion engine or steam engine.The three main functions of piston rings in reciprocating engines are:...

s, bearings
Bearing (mechanical)
A bearing is a device to allow constrained relative motion between two or more parts, typically rotation or linear movement. Bearings may be classified broadly according to the motions they allow and according to their principle of operation as well as by the directions of applied loads they can...

, gasket
thumb|sright|250px|Some seals and gaskets1. [[o-ring]]2. fiber [[Washer |washer]]3. paper gaskets4. [[cylinder head]] [[head gasket|gasket]]...

s, oil seals. When done by a competent engine builder the engine will perform as new. The engine may be overhauled to 'new limits' or 'service limits', or a combination of the two using used parts, new original equipment manufacturer
Original Equipment Manufacturer
An original equipment manufacturer, or OEM, manufactures products or components that are purchased by a company and retailed under that purchasing company's brand name. OEM refers to the company that originally manufactured the product. When referring to automotive parts, OEM designates a...

 (OEM) parts, or new aftermarket
Aftermarket (automotive)
The automotive aftermarket is the secondary market of the automotive industry, concerned with the manufacturing, remanufacturing, distribution, retailing, and installation of all vehicle parts, chemicals, tools, equipment and accessories for light and heavy vehicles, after the sale of the...

 parts. The engine's previous operating history is maintained and it is returned with zero hours since major overhaul.

Many times aftermarket part manufacturers are the OEM part suppliers to major engine manufacturers (e.g. Ishino manufactures both the OEM and the aftermarket cylinder head and valve cover gaskets for the Nissan VG30E. Often the Nissan logo is imprinted on the OEM part while the OEM suppliers brand will be imprinted on the same exact part when offered aftermarket.)

A top overhaul only covers the replacement of components inside the cylinder head
Cylinder head
In an internal combustion engine, the cylinder head sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder, forming the combustion chamber. This joint is sealed by a head gasket...

 without removing the engine from the vehicle, such as valve and rocker arm replacement. It may or may not include a valve job. A major overhaul however covers the whole engine assembly, which requires the engine to be removed from the vehicle and transferred to an engine stand. An overhauled engine refers to a major overhaul. By comparison, a major overhaul costs more than a top overhaul.

'New limits' are the factory service manual's approved fits and tolerances that a new engine is manufactured to. This may be accomplished by using standard or approved undersized and oversized tolerances. 'Service limits' are the factory service manual's allowable wear fits and tolerances that a new limit part may deteriorate to and still be a usable component. This may also be accomplished using standard and approved undersized and oversized tolerances.


A 'rebuilt engine' is an engine that has been overhauled using new and used parts to new limits by the manufacturer or an entity approved by the manufacturer. The engine's previous operating history is eradicated and it comes to you with zero hours total time in service, even though the engine may have had used components installed that have many hours of previous operating history. Production rebuilders or marketing material sometimes use the word 'remanufactured' to describe these engines.


Remanufacturing is the process of disassembly and recovery at the module level and, eventually, at the component level. It requires the repair or replacement of worn out or obsolete components and modules. Parts subject to degradation affecting the performance or the expected life of the whole are...

 is a term to mean an engine put together to match factory specifications e.g. "as new". Although often a buyer may take this to mean all-new parts are used, this is not always the case. At the very least, the cylinder block
Cylinder block
A cylinder block is an integrated structure comprising the cylinder of a reciprocating engine and often some or all of their associated surrounding structures...

 will be used, as may most other parts. High-quality rebuilds will often include new pistons and line-boring of the crankshaft and camshaft bores.


In engine blueprinting, all the specifications are double-checked. Usually this indicates closer-than-factory tolerances, with custom specifications appropriate for a street car or a race car. The goals are either to re-manufacture the engine to the rated power for its manufacturer's design (because not all mass-production engines put out the rated power), or rebuild the engine to make more power from a given design than otherwise intended (because custom engines can often be redesigned to different specifications). Blueprinted components allow for a more exact balancing of reciprocating parts and rotating assemblies so that less power is lost through excessive engine vibrations and other mechanical inefficiencies.

Ideally, blueprinting is performed on components removed from the production line before normal balancing and finishing. If finished components are blueprinted, there is the risk that the further removal of material will weaken the component. However, lightening components is generally an advantage in itself provided balance and adequate strength are both maintained, and more precise machining will in general strengthen a part by removing stress points, so in many cases performance tuners are able to work with finished components.

For example, an engine manufacturer may list a piston ring end-gap specification of 0.003 to 0.005 inches for general use in a consumer automobile application. For an endurance racing engine which runs hot, a "blueprinted" specification of 0.0045" to 0.0050" may be desired. For a drag-racing engine which runs only in short bursts, a tighter 0.0035 to 0.0040 inch tolerance may be used instead. Thus "blueprint" can mean tighter or looser clearances, depending on the goal.


The 'Igniscope' electronic ignition tester was produced by English Electric
English Electric
English Electric was a British industrial manufacturer. Founded in 1918, it initially specialised in industrial electric motors and transformers...

 during the 1940s, originally as 'type UED' for military use during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. The post-war version, 'type ZWA' electronic ignition tester, was advertised as "the first of its kind, employing an entirely new technique".

The Igniscope used a cathode ray tube
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...

, giving an entirely visual method of diagnosis. It was invented by D. Napier & Son Ltd., a subsidiary of English Electric, and British Patents 495478, 495547 and 563502 applied. The Igniscope was capable of diagnosing latent and actual faults in both coil
Ignition coil
An ignition coil is an induction coil in an automobile's ignition system which transforms the battery's 12 volts to the thousands of volts needed to create an electric spark in the spark plugs to ignite the fuel...

 and magneto
A magneto is a type of electrical generator.Magneto may also refer to:* Magneto , permanent magnetic alternating current rotary generator* ignition magneto, magnetos on internal combustion engines...

 ignition systems, including poor battery supply bonding, points and condenser problems, distributor failure and spark plug gap. One feature was a "loading" control which made latent faults more visible.

The UED manual includes the spark plug firing order
Firing order
The firing order is the sequence of power delivery of each cylinder in a multi-cylinder reciprocating engine.This is achieved by sparking of the spark plugs in a gasoline engine in the correct order, or by the sequence of fuel injection in a Diesel engine...

 of the tanks and cars used by the British armed forces

See also

  • Car tuning
    Car tuning
    Car tuning is both an industry and a hobby, in which an automobile is modified in order to improve its performance, handling and appearance. As most vehicles leave the factory set up for average driver expectations and average conditions, tuning has become a way to personalize the characteristics...

  • Crome
    Crome, which stands for "Cui's ROM Editor", is a scriptable OBD1 Honda ROM editor which allows users to edit and add extra features to the stock Honda ECU. It was written by John Cui....

  • Hondata
    Hondata, Inc. is an American corporation that specializes in the modification and reprogramming of certain Honda and Acura engine control units . Its products are popular with certain members of the import scene concerned with engine swapping and tuning...

  • MegaSquirt
    MegaSquirt is the registered trademark of an aftermarket electronic fuel injection controller designed to be used with a wide range of spark-ignition internal combustion engines It is a complete standalone fuel injection controller with software and hardware, developed by Bruce Bowling and Al...

  • Nitromethane
    Nitromethane is an organic compound with the chemical formula . It is the simplest organic nitro compound. It is a slightly viscous, highly polar liquid commonly used as a solvent in a variety of industrial applications such as in extractions, as a reaction medium, and as a cleaning solvent...

  • Nitrous oxide engine
  • Otto cycle
    Otto cycle
    An Otto cycle is an idealized thermodynamic cycle which describes the functioning of a typical reciprocating piston engine, the thermodynamic cycle most commonly found in automobile engines....

  • Racing fuel
    Racing fuel
    Racing fuel can refer to many different common fuels used in motorsports:*Leaded gasoline, formerly used by the NASCAR series and other motorsports**Use of leaded gasoline in NASCAR*Nitromethane and methanol fuel, used by Top Fuel drag racing...

  • Shift kit
    Shift kit
    A Shift kit is an aftermarket component for automobiles to improve how well the car shifts between gears. Kits are mode for both automatic and manual transmissions.-Manual transmission kit:...

  • Uberdata
    Uberdata is a ROM editing software designed specifically for On Board Diagnostics Honda Engine control units. It was created by Blake Warner...

  • Water injection (engines)
    Water injection (engines)
    In internal combustion engines, water injection, also known as anti-detonant injection, is spraying water into the cylinder or incoming fuel-air mixture to cool the combustion chambers of the engine, allowing for greater compression ratios and largely eliminating the problem of engine knocking...