Spark plugs and Resistor Caps

2021-10-13 16:02:00 / / Comments 0
Technical information on motorbike spark plugs and resistor caps, fault detection and troubleshooting

NGK Spark plugs

The spark plug program from NGK includes many different spark plug types:
From the standard spark plug to the precious metal spark plug to the double precious metal spark plug.
NGK offers the optimum solution for many engines, as an original equipment manufacturer for leading passenger car and motorcycle manufacturers, in the winning cars of Formula 1, in motorcycle racing and in vehicles used in everyday road traffic.
The most important manufacturers of two-wheelers, small engines and boat engines also rely on spark plugs from NGK. The NGK product range offers the right product for almost every engine.precious metal spark plugs have very specific characteristics in terms of service life and performance.
Spark plugs with V-notches in the center electrode ignite closer to the ignitable mixture.
V-Line and LPG LaserLine - Perfect for repair service and efficient work.
LPG LaserLine is a special spark plug range for gas-powered engines.

Function

There have been no profound changes in the basic design of the spark plug over the past 50 years.
The spark plug consists of a metal core housed in a ceramic insulator.
This is surrounded by a metal shell consisting of a thread that is turned into the cylinder head and usually has a hexagonal section at the top,
to allow installation or removal of the spark plugs.
When high voltage is applied to the spark plug, a spark should jump from the center electrode to the ground electrode.

Requirements for spark plugs

If a gasoline engine is to run properly, the spark must be reliably controlled.
Misfiring causes unburned air-fuel mixture to enter the exhaust, where it first burns inside the hot catalytic converter. A few misfires may be enough to damage the catalytic converter or even render it completely unusable.
If one considers that a spark plug has to ignite between 500 and 3500 times per minute, it becomes clear how great the contribution of modern spark plug technology is, for example, to compliance with current emission standards and to reducing fuel consumption.
Expectations regarding the service life of a spark plug have also become much higher over recent years.
The conditions have become more difficult due to new, more efficient and more powerful engines but have been solved by continuous development, research and new, better materials.

Installation of spark plugs

Replacing spark plugs is one of the easier jobs for the vehicle owner if it is easily accessible, there are some things to consider.

In the modern vehicles it is important to have the right tools. Otherwise, there is a risk of damaging the spark plugs when unscrewing or screwing them in.


In engines equipped with aluminum cylinder heads, the aluminum expands more than the spark plug when heated, causing the spark plug to seize. Therefore, a spark plug should only be changed when the engine has cooled down.

A torque wrench is required to install a spark plug. The specified tightening torque of the spark plug must be observed.

Incorrect tightening torque can lead to spark plug failure. If it is too low, there is a risk of compression loss and overheating. Insulator breakage or breakage of the center electrode due to vibration is also conceivable.

Torque too high, it can cause the spark plug to snap off. The housing may stretch or twist. The heat dissipation zones are disturbed. Overheating and fusion of the electrodes up to engine damage can be the result.

Guide values for aluminum head and 18 mm spark plug thread are 20-30 Nm. With 14 mm thread 10-20 Nm. (Observe engine manufacturer's specifications)

Installation quick guide for spark plugs

Loosen the old spark plug.
Before removal, remove any encrustations and dirt from the installation shaft with compressed air.
Unscrew the old spark plug.
Clean spark plug bore.
Screw in new spark plug by hand.
Do not use spark plugs that have fallen onto a hard surface.
Tighten spark plug to specified torque.

Spark plug damage patterns

Normal appearance of a used spark plug:
An intact spark plug has a white-gray discoloration.
It comes from fuel additives that do not burn completely and is the result of controlled, normal combustion.

Deposits

Heavy deposits can be caused by poor fuel quality and when oil or coolant burns in faulty or worn engines. Deposits smolder and cause glow ignitions, which can lead to insulator fractures and engine damage.
Insulator fractures also often occur due to improper torque or in that the insulators were damaged prior to installation.
When a spark plug overheats, the center and ground electrodes fuse together.

Melting

When a spark plug overheats, the center and ground electrodes can fuse together.
In such cases, possible melting of the piston cannot be ruled out.
The causes can be the wrong spark plug (wrong heat value) or a defect of the engine ( knocking combustion or glow ignition ).

Sooting

Sooting can occur with frequent short-distance operation or incorrect heat value (too cold) of the spark plug. The spark plug then does not reach its self-cleaning temperature of 450 °C.

spark plugs are available for the following vehicle models, click on a brand to open the tab with the models

 

NGK Spark plug connector

NGK's spark plug caps feature a resistor element made of high quality ceramic material that is long enough to prevent internal flashover and still provide constant resistance with only minor fluctuations under overload conditions.

The spark plug cap body is made of rugged phenolic resin that can withstand high heat and high voltage. The special rugged rubber liners of the spark plug connectors at both ends prevent moisture from causing electrical leakage.

The combined use of resistor covers and resistor spark plugs is more efficient in suppressing ignition noise from engines in motorcycles, snowmobiles, farm tractors, etc.

NGK's spark plug caps are engineered to the same exacting standards as our other world-class products. The spark plug cap must provide a secure connection between the high voltage ignition wires and the spark plug. It must ensure that there is no leakage current at this connection that could affect engine performance. On many motorcycles, for example, spark plug connectors are exposed to the elements and must function perfectly in the harshest weather conditions.

Spark plug connectors are manufactured for many applications, and many are of the resistance type, which provides electrical noise rejection across all frequencies without affecting engine performance.

spark plug connectors are available for the following vehicle models, click on a brand to open the tab with the models