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Spark Plugs - When 2 Change
Spark Plugs - When 2 Change
Sometimes you need to know the exact time to change the Sparks Plugs because you think the guy @StealerShip (DealerShip) or the JerkShop (Workshop.... but not FLy's ) is trying to ripp you off your money....
So, I thought it would be better if I try to post this article to let you know yourself. Its also a good example for the Hardcore (not blue) DIYers!
This can also help in recognising the condition of the engine in some situations.
==================================
An examination of used spark plugs can reflect the accuracy of heat range application. Close scrutiny of the firing end can also suggest a variety of possible engine conditions and point the way to achieving improved spark plug and engine performance.
The quantity, color or overall appearance, as well as the chemical make-up of the deposits, are all important in making the correct diagnosis.
So, lets rock!!!
==============================
NORMAL
A normal condition is shown below. This plug has been running at the correct temperature in a "healthy" engine. Operating in such a desirable environment results in deposits that will be light tan or gray in color with most grades of commercial gasoline.
If LP Gas or natural gas has been used, the color will be almost brown.
===============================
OIL FOULED
A spark plug shorted by excessive oil entering the combustion chamber is shown below. This is often caused by piston rings or cylinder walls that are badly worn. Oil may also be pulled into the chamber because of excessive clearance in the valve stem guides, or badly worn valve stem seals. If the PCV valve is plugged or inoperative, it can cause a buildup of crankcase pressure. This condition can force oil and oil vapors past the rings and valve guides into the combustion chamber.
=====================
CARBON FOULED
Basically, soft, sooty carbon deposits, as shown below, have a dry, black appearance. If only one or two plugs in a set are fouled, it is a good practice to check for sticking valves, a cracked distributor cap, or bad secondary ignition wires. Fouling of the entire set might result from an incorrect heat range spark plug or an over-rich air/fuel mixture caused by a clogged air cleaner filter element, a sticking heat riser valve, or a faulty choke. Fuel injectors that malfunction can also lead to this condition.
Other causes include weak ignition system voltage or an inoperative pre-heating system (carburetor intake air) or poor cylinder compression.
===========================
WORN
This spark plug shown below has served its useful life and should be replaced. Voltage required to fire the plug has approximately doubled and will continue to increase the longer the engine operates.
Even higher voltage requirements (as much as 100%) above normal may occur when the engine is accelerated quickly. Poor engine performance and a loss of fuel economy are traits of worn spark plugs.
2 Answers
299 views |
So, I thought it would be better if I try to post this article to let you know yourself. Its also a good example for the Hardcore (not blue) DIYers!
This can also help in recognising the condition of the engine in some situations.
==================================
An examination of used spark plugs can reflect the accuracy of heat range application. Close scrutiny of the firing end can also suggest a variety of possible engine conditions and point the way to achieving improved spark plug and engine performance.
The quantity, color or overall appearance, as well as the chemical make-up of the deposits, are all important in making the correct diagnosis.
So, lets rock!!!
==============================
NORMAL
A normal condition is shown below. This plug has been running at the correct temperature in a "healthy" engine. Operating in such a desirable environment results in deposits that will be light tan or gray in color with most grades of commercial gasoline.
If LP Gas or natural gas has been used, the color will be almost brown.
===============================
OIL FOULED
A spark plug shorted by excessive oil entering the combustion chamber is shown below. This is often caused by piston rings or cylinder walls that are badly worn. Oil may also be pulled into the chamber because of excessive clearance in the valve stem guides, or badly worn valve stem seals. If the PCV valve is plugged or inoperative, it can cause a buildup of crankcase pressure. This condition can force oil and oil vapors past the rings and valve guides into the combustion chamber.
=====================
CARBON FOULED
Basically, soft, sooty carbon deposits, as shown below, have a dry, black appearance. If only one or two plugs in a set are fouled, it is a good practice to check for sticking valves, a cracked distributor cap, or bad secondary ignition wires. Fouling of the entire set might result from an incorrect heat range spark plug or an over-rich air/fuel mixture caused by a clogged air cleaner filter element, a sticking heat riser valve, or a faulty choke. Fuel injectors that malfunction can also lead to this condition.
Other causes include weak ignition system voltage or an inoperative pre-heating system (carburetor intake air) or poor cylinder compression.
===========================
WORN
This spark plug shown below has served its useful life and should be replaced. Voltage required to fire the plug has approximately doubled and will continue to increase the longer the engine operates.
Even higher voltage requirements (as much as 100%) above normal may occur when the engine is accelerated quickly. Poor engine performance and a loss of fuel economy are traits of worn spark plugs.
Gari.pk User 3812 asked on 08 Jul 2010 12:57:13 pm
2 Answers 
Zain - on 08 Jul 2010 12:57:59 pmINSULATOR GLAZING
This condition may cause misfiring at high engine RPM. Shiny deposits usually suggest that temperatures have suddenly increased during hard acceleration. As a result, normal metallic deposits do not have a chance to slough off the plug and they melt and form a conductive coating which causes the misfire. Yellow or tan deposits, as shown below, usually indicate the use of leaded fuel.
=============================
MECHANICAL DAMAGE
Mechanical damage to the firing end, as shown below, is caused by some foreign object in the combustion chamber. Since small objects can travel from one cylinder to another (because of valve overlap), the other cylinders should always be checked to prevent reoccurance of damage.
When working on an engine, it is advisable to keep the carburetor throat (or throttle body openings on central type fuel injected engines) covered. That precaution also applies to spark plug holes.
=====================
This condition may cause misfiring at high engine RPM. Shiny deposits usually suggest that temperatures have suddenly increased during hard acceleration. As a result, normal metallic deposits do not have a chance to slough off the plug and they melt and form a conductive coating which causes the misfire. Yellow or tan deposits, as shown below, usually indicate the use of leaded fuel.
=============================
MECHANICAL DAMAGE
Mechanical damage to the firing end, as shown below, is caused by some foreign object in the combustion chamber. Since small objects can travel from one cylinder to another (because of valve overlap), the other cylinders should always be checked to prevent reoccurance of damage.
When working on an engine, it is advisable to keep the carburetor throat (or throttle body openings on central type fuel injected engines) covered. That precaution also applies to spark plug holes.
=====================
Muzammil - on 08 Jul 2010 12:58:25 pmOVERHEATED
An example of overheating is shown below. Note the dead white or gray insulator nose which appears "blistered." Electrode gap wear rate will be considerably in excess of that normally expected. This is often caused by overadvanced ignition timing, poor engine cooling system efficiency (scale, stoppages, low level), a very lean A/F mixture, a leaking intake manifold, or the use of a spark plug too hot for the application.
================================
SPLASHED FOULED
Splashed fouling, as shown below, may sometimes occur after a long-delayed tune-up. Here, deposits accumulated after long periods of misfiring or low power operation may be suddenly loosened when normal combustion temperatures are restored after a set of new plugs has been installed. During a high-speed run, these materials shedding off the piston are thrown against the hot insulator surfaces.
An example of overheating is shown below. Note the dead white or gray insulator nose which appears "blistered." Electrode gap wear rate will be considerably in excess of that normally expected. This is often caused by overadvanced ignition timing, poor engine cooling system efficiency (scale, stoppages, low level), a very lean A/F mixture, a leaking intake manifold, or the use of a spark plug too hot for the application.
================================
SPLASHED FOULED
Splashed fouling, as shown below, may sometimes occur after a long-delayed tune-up. Here, deposits accumulated after long periods of misfiring or low power operation may be suddenly loosened when normal combustion temperatures are restored after a set of new plugs has been installed. During a high-speed run, these materials shedding off the piston are thrown against the hot insulator surfaces.
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Spark Plugs - When 2 Change
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