All about spark plugs page 1 of 5

[Chongo]

Spark plugs are one of the most misunderstood components
of an engine. Numerous questions have surfaced over the years, leaving many people confused.
This guide is designed to assist the technician, hobbyist, or race mechanics in understanding, using, and troubleshooting spark plugs. The information contained in this guide applies to
all types of internal combustion engines.
Spark plugs are the "window" into the engine , and can be used as a valuable diagnostic tool. Like a patient's thermometer, the spark plug displays symptoms and conditions of the engine. The experienced tuner can analyze these symptoms to track down the root cause of many problems, or determine air/fuel ratios.
SPARK PLUG BASICS:
The spark plug has two primary functions:
• Ignite air/fuel mixture
• Transfer heat from the combustion chamber
Spark plugs carry electrical energy and turn fuel into working energy. A sufficient amount of voltage must be supplied by the ignition system to spark across the spark plug's gap. This is
called "Electrical Performance."
The temperature of the spark plug's firing end must be kept low enough to prevent pre-ignition, but high enough to prevent fouling. This is called "Thermal Performance", and is
determined by the heat range selected.
It's important to remember spark plugs do not create heat, they only remove heat. The spark plug works as a heat exchanger
by pulling unwanted thermal energy away from the combustion chamber, and transferring the heat to the engine's cooling
system. The heat range is defined as a plug's ability to
dissipate heat.
The rate of heat transfer is determined by:
• The insulator nose length
• Gas volume around the insulator nose
• The materials/construction of the center electrode and porcelain insulator

A spark plug's heat range has no relationship to the actual voltage transferred through the spark plug. Rather, the heat range is a measure of the spark plug's ability to remove heat from the combustion chamber. The heat range measurement is determined by several factors; the length of the ceramic center insulator nose and its' ability to absorb and transfer combustion heat, the material composition of the insulator and center electrode material
The insulator nose length is the distance from the firing tip of the insulator to the point where insulator meets the metal shell. Since the insulator tip is the hottest part of the spark plug, the tip temperature is a primary factor in pre-ignition and fouling. Whether the spark plugs are fitted in a lawnmower, boat, or a race car, the spark plug tip temperature must remain between 500C-850°C. If the tip temperature is lower than 500°C, the insulator area surrounding the center electrode will not be hot enough to burn off carbon and combustion chamber deposits. These accumulated deposits can result in spark plug fouling leading to misfire. If the tip temperature is higher than 850°C the spark plug will overheat which may cause the ceramic around the center electrode to blister and the electrodes to melt. This may lead to pre-ignition/detonation and expensive engine damage. In identical spark plug types, the difference from one heat range to the next is the ability to remove approximately 70°C to 100°C from the combustion chamber. A projected style spark plug firing tip temperature is increased by 10°C to 20°C.
Tip Temperature and Firing End Appearance

The firing end appearance also depends on the spark plugs tip temperature. There are three basic diagnostic criteria for spark plugs: good, fouled and overheated. The borderline between the fouling and optimum operating regions (500 to 750 degrees F) is called the spark plug self-cleaning temperature. The temperature at this point is where the accumulated carbon and combustion deposits are burned off.

Keep in mind the insulator nose length is a determining factor in the heat range of a spark plug, the longer the insulator nose, the less heat is absorbed, and the further the heat must travel into the cylinder head water jackets. This means the plug has a higher internal temperature, and is said to be a hot plug. A hot spark plug maintains a higher internal operating temperature to burn off oil and carbon deposits, and has no relationship to spark quality or intensity.
Conversely, a cold spark plug has a shorter insulator nose and absorbs more combustion chamber heat. This heat travels a shorter distance, and allows the plug to operate at a lower internal temperature. A colder heat range is necessary when the engine is modified for performance, subjected to heavy loads, or is run at a high rpm for a significant period of time. Colder spark plugs remove heat quicker, reducing the chance of pre-ignition/detonation. Failure to use a cooler heat range in a modified application can lead to spark plug failure and severe engine damage.

Below is a list of external influences on a spark plug's operating temperature. The following symptoms or conditions may have an effect on the actual temperature of the spark plug. The spark plug cannot create these conditions, but it must be able to cope with the levels of heat...if not, the performance will suffer and engine damage can occur.
Air/Fuel Mixtures seriously affect engine performance and spark plug operating temperatures.
• Rich air/fuel mixtures cause tip temperature to drop, causing fouling and poor driveability
• Lean air/fuel mixtures cause plug tip and cylinder temperature to increase, resulting in pre-ignition, detonation, and possibly serious spark plug and engine damage
• It is important to read spark plugs many times during the tuning process to achieve the optimum air/ fuel mixture
Higher Compression Ratios/Forced Induction will elevate spark plug tip and in-cylinder temperatures
• Compression can be increased by performing any one of the following modifications:

a) reducing combustion chamber volume (i.e.: domed pistons, smaller chamber heads, mill ing heads, etc.)

b) adding forced induction (Nitrous, Turbocharging or Supercharging)

c) camshaft change
• As compression increases, a colder heat range plug, higher fuel octane, and careful attention to ignition timing and air/fuel ratios are necessary. Failure to select a colder spark plug can lead to spark plug/engine damage
Advancing Ignition Timing
• Advancing ignition timing by 10° causes tip temperature to increase by approx. 70°-100° C
Engine Speed and Load
• Increases in firing-end temperature are proportional to engine speed and load. When traveling at a consistent high rate of speed, or carrying/pushing very heavy loads, a colder heat range spark plug should be installed

 

[Chongo]

page 2 of 5

Ambient Air Temperature
• As air temperature falls, air density/air volume becomes greater, resulting in leaner air/fuel mixtures.
• This creates higher cylinder pressures/temperatures and causes an increase in the spark plug's tip temperature. So, fuel delivery should be increased.
• As temperature increases, air density decreases, as does intake volume, fuel delivery should be decreased
Humidity
• As humidity increases, air intake volume decreases
• Result is lower combustion pressures and temperatures, causing a decrease in the spark plug's temperature and a reduction in available power.
• Air/fuel mixture should be leaner, depending upon ambient temperature.
Barometric Pressure/Altitude
• Also affects the spark plug's tip temperature
• The higher the altitude, the lower cylinder pressure becomes. As the cylinder temperature decreases, so does the plugs tip temperature
• Many mechanics attempt to "chase" tuning by changing spark plug heat ranges
• The real answer is to adjust air/fuel mixtures by rejetting in an effort to put more air back into the engine


Types of Abnormal Combustion
Pre-ignition
• Defined as: ignition of the air/fuel mixture before the pre-set ignition timing mark
• Caused by hot spots in the combustion chamber...can be caused
(or amplified) by over advanced timing, too hot a spark plug, low octane fuel, lean air/fuel mixture, too high compression, or insufficient engine cooling
• A change to a higher octane fuel, a colder plug, richer fuel mixture,
or lower compression may be in order
• You may also need to ****** ignition timing, and check vehicle's cooling system
• Pre-ignition usually leads to detonation; pre-ignition an detonation are two separate events
Detonation
• The spark plug's worst enemy! (Besides fouling)
• Can break insulators or break off ground electrodes
• Pre-ignition most often leads to detonation
• Plug tip temperatures can spike to over 3000°F during the combustion process (in a racing engine)
• Most frequently caused by hot spots in the combustion chamber.
Hot spots will allow the air/fuel mixture to pre-ignite. As the piston is being forced upward by mechanical action of the connecting rod, the pre-ignited explosion will try to force the piston downward. If the piston can't go up (because of the force of the premature explosion) and it can't go down (because of the upward mo-tion of the connecting rod), the piston will rattle from side to side. The resulting shock wave causes an audible pinging sound. This is detonation.
• Most of the damage than an engine sustains when "detonating" is from excessive heat
• The spark plug is damaged by both the elevated temperatures and the accompanying shock wave, or concussion
Misfires
• A spark plug is said to have misfired when enough voltage has not been delivered to light off all fuel present in the combustion chamber at the proper moment of the power ****** (a few degrees before top dead center)
• A spark plug can deliver a weak spark (or no spark at all) for a variety of reasons...defective coil, too much compression with incorrect
plug gap, dry fouled or wet fouled spark plugs, insufficient ignition timing, etc.
• Slight misfires can cause a loss of performance for obvious reasons (if fuel is not lit, no energy is be-ing created)


• Severe misfires will cause poor fuel economy, poor driveability, and can lead to engine damage
Fouling
• Will occur when spark plug tip temperature is insufficient to burn off carbon, fuel, oil or other deposits
• Will cause spark to leach to metal shell...no spark across plug gap will cause a misfire
• Wet-fouled spark plugs must be changed...spark plugs will not fire
• Dry-fouled spark plugs can sometimes be cleaned by bringing engine up to operating temperature
• Before changing fouled spark plugs, be sure to eliminate root
cause of fouling

As the source for spark plugs, we pride ourselves in the technical spark plug information contained on our website. We enjoy providing that technical information on the forums, so here are some of the common topics and questions in regards to spark plugs. If you have any additional questions, please feel free to ask!

Subject covered by this post:

Basic Spark Plug Construction
How do I cross reference from one brand to another?
What are resistor plugs?
What are V-cut or U-grooved plugs?
Multi-Ground Plugs
What are Fine Wire Plugs?
What Is Platinum?
What Is Iridium?
How long will my iridium plugs last?
Can I use Iridium plugs with nitrous injection?



Basic Spark Plug Construction

Let's start out with the basic construction of a spark plug.

Starting at the top, the TERMINAL can come 3 ways:

 

[Chongo]

page3 of 5

stud - some wires are made to fit over plugs that don't have a terminal nut on top, the plug is produced with the terminal nut left off.
solid - the terminal nut is permanent and can not be removed. Used particularly in the motorsport and marine industry when there is a lot of movement and vibration and a removable terminal nut could come loose.
removable - the plug comes with a terminal nut, but it can be removed.


HEX - This is the area your socket grabs when removing or installing plug. For automotive applications, plugs usually come with a 5/8 or 13/16 hex. Vehicles prior to about 1980 allow for a 13/16 hex, most after 1980 only allow 5/8.

SEAT - Plugs are available in a tapered seat or with a gasket. The two are not interchangable - in order to use a plug with a tapered seat, your cylinder heads must have been made specifically for the use of a plug with a tapered seat.


REACH - The plug reach is measured from the seat to the end of the threaded are (do not include ground strap in measurement).


THREAD DIAMETER - Accurate Measurement of the cylinder head or removed plug is necessary to determine the plug diameter, which may range form 8mm to 18mm.


GROUND ELECTRODE - Ground electrodes come in a variety of shapes and sizes. They are also called by a variety of names depending on manufacturer, IE: trapezoid cut ground, tapered cut ground, fine wire ground, angled ground, trimmed side electrode, wedge shaped ground, inverted V-tip ground, cut back ground, etc. All have the same purpose, to reduce quenching and shadowing. Ground straps will be discussed in more detail in future technical threads.


CENTER ELECTRODE - A traditional center electrode is 2.5mm. Manufacturers have improved spark plug performance by creating fine-wire, taper cut, necked down and v-power center electrodes. Each of these will be discussed in further detail in future technical threads.


GAP - A spark plugs’ tip temperature and the voltage necessary to fire the plug are directly affected by the gap setting. Most manufacturers set the gap from the factory for that plugs most popular application. Unfortunately, that plug may have hundreds of applications from automobiles to golf carts. Setting the gap for your particular engine is important as insufficient spark plug gap can cause pre-ignition, detonation and even engine damage. Whereas too much gap can result in a higher rate of misfires, loss of power, plug fouling and poor fuel economy. Even if the preset gap is supposed to match your motor, it is always best to physically check that the gap is adjusted properly for your motor prior to installation as the gap may have been changed during shipping.



What are resistor plugs?

At the moment the spark jumps the gap it causes a high frequency burst of energy, this is known as RFI (radio frequency interference). This is why resistor spark plugs were introduced in the mid 1960's. Placing a resistor within the spark plug suppresses the RFI. Without resistor plugs in your car you can experience static on your radio as well as interfere with other sensitive electronic equipment. Some later model vehicles as well as newer Powersport engines must use resistor plugs for a proper "talkback" to the electronic ignition. Outboard marine Capacitive Discharge Ignition (CDI) such as used on some Johnson and Evinrude marine engines require a special inductive type resistor (such as a Champion Q-type or NGK Z-type). Use of non-inductive resistor type plugs on these motors can cause misfire and poor performance.






What are V-cut or U-grooved plugs?

V-cut ground electrodes are called a variety of names depending on manufacturer. Although they look similar, they may be called a tapered cut ground, trimmed side electrode, wedge shaped ground, v-trimmed electrode, inverted v-tip ground, v-power (NGK) or U-groove (Denso). So what's the point? The v-cut give the flame a groove to grow in and forces the spark to the outer edge of the ground electrode - placing it close to the air/fuel mixture and creating a larger flame that ignites quicker for a more complete combustion, even in the case of lean air/fuel mixture. A conventional, flat ground electrode design of regular plugs crushes the flame (sometimes called quenching), thereby preventing full spark potential.


Standard Plug Causes Quenching :


NGK V-Power Reduces Quenching

Denso U-Groove Reduces Quenching







Multi-ground Plugs

Some combustion chamber designs, such as rotary motors, require that the spark plugs have the ground electrode placed to the side of the center electrode rather

 

[Chongo]

page 4 of 5

than below as on a traditional plug. This firing tip design tends to erode the tip of the ground electrode faster than a traditional plug, and as erosion at these points creates a larger gap between the center and ground electrodes, plug misfire will occur. Thus, by having more ground electrodes, you extend plug life. It is important to note that multi-ground does not mean multi-spark - electricity follows the path of least resistance, there will still only be one spark at a time. Therefore a multi-ground plug will not perform any better and may actually perform worse than a traditional plug, unless the engine is designed for a multiple ground plug.


What are Fine Wire Plugs?

Fine wire center electrodes come under a variety of names depending on manufacturer, IE - Tapered point, Ultra-Fine electrode, Taper cut electrode, Necked down electrode). Originally designed to improve starting and reduce fouling in two-****** engines, this design was found to improve performance in four-****** engines as well.

All operate on primarily the same principle, a spark plug with a fine wire electrode will perform better than a traditional plug. There are two reasons for this, first is because a smaller center electrode requires less voltage to jump the gap. This means fewer misfires, which should be seen in higher mileage and more horsepower. The second reason is smaller center electrodes reduce quenching. The smaller center electrodes have required exotic metals such as platinum or iridium so that they can still maintain (and usually surpass) the longevity of a traditional spark plug.

Currently the finest wire performance plugs available are made by Denso at 0.4mm diameter, by NGK at 0.7mm diameter, and by Champion at 1.1mm, a traditional center electrode is typically 2.0 to 2.5mm.


What is Platinum?


Platinum is a precious metal used by nearly all spark plug manufacturers on their long life and/or performance spark plugs. This is because of platinums high melting point which makes it useful in two ways.

#1 - On long life spark plugs, a thin wafer of platinum is bonded at the firing point to the center electrode (and possibly ground electrode) solely so they dont wear as fast as a traditional plug.

#2 - On a fine wire performance plug, the very tip of the center electrode is made of platinum so that the fine wire tip will last longer.

Do not be fooled, all platinum plugs are not created equal, Platinum is a very expensive precious metal, a $2 platinum spark plug will not have much platinum in it, and therefore will not last as long as a $12 platinum spark plug. Some platinum plugs have only the center electrode tipped with platinum, while others have both the center and ground electrodes platinum tipped.


(By the way, it is still not suggested that platinum plugs be used on vehicles with nitrous injection. Thus far, there has been no problems reported regarding using iridium plugs with nitrous.)


What Is Iridium?


Iridium is a precious metal that is 6 times harder and 8 times stronger than platinum, it has a 1,200 degree higher melting point than platinum, ( 2460 degrees F ), and conducts electricity better. This makes it possible to create the finest wire center electrode ever. (See "What is a fine wire plug" for information on the benefits of fine wire plugs)

Prior till now, spark plug manufacturers have favored platinum for their long life or performance spark plugs due to its high melting point. Also, the technology did not exist to machine and bond iridium on a spark plug electrode (at least in a cost effective manner).

Champion spark plugs have produced iridium industrial and aviation spark plugs since the 1960's, but they still sell for over a hundred dollars per plug. Just now is the technology cost effective to use iridium in a spark plug for automotive applications.

The strength, hardness and high melting point of iridium make it very well suited for a fine wire plug. The primary iridium plug manufacturers at this time are Denso with a 0.4mm center electrode, while Champion and NGK have 0.7mm center electrodes. These are the best performance plugs on the market for traditional automotive use and many racing applications.

SIDENOTE: Thus far the tech's we have spoken with report no problems using iridium plugs with Nitrous.


Metal Properties

How long will my iridium spark plugs last?

A traditional iridium plug such as a Denso ITL16 or NGK LZTR6AIX-13 both have iridium tipped center electrodes, however the ground electrodes are the traditional nickel construction(the same ground electrode that single platinum and traditional 'copper' plugs have). The ground electrode will wear out first. The manufacturers are saying 40,000 to 60,000 miles on iridium plugs. But they have to temper their projections as driving conditions and motor modifications differ. Typically we have found you can expect 60,000 to 80,000 miles on an unaltered motor. (the family mini-van has had the Denso's for 76,000 miles, I examined 2 of the plugs, they had some minor spooning on the ground electrode, I put them back in and will likely change them in another 5,000 miles).

Both Denso iridium racing plug and some NGK Iridium racing plugs have iridium center and a platinum ground electrodes. If installed to a regular engine they would likely last longer than most people keep their car (barring any motor problems that can cause premature plug death). But, these usually come in heat ranges too cold for an unaltered motor and are usually used in racing applications where all bets are off.

For the traditional automotive market, the longest lasting plugs are the NGK "IFR" series and the Denso "SK" series. These have Iridium center and platinum tipped

ground electrodes, however these are extremely limited in application as they only manufactured these in a couple of heat range configurations.






Nitrous 411 & FAQs

 

[Chongo]

5 of 5

Nitrous Oxide is an efficient means of getting more oxygen into the combustion chamber. Initially the
N2O injection will cool the incoming charge due to the energy expended on vaporization into the air fuel mixture. However, do to the dramatic increase in power output, the sustained use of N2O increases cylinder temperatures to the point you may require a spark plug one or two heat ranges colder. If the nitrous is used only for very short bursts, (less than 10 seconds), then the standard plug can likely be used with no spark plug heat change necessary.

Can I use platinum plugs with nitrous injection?

No, it is not suggested to use platinum plugs with nitrous oxide injection.
There have been instances where the platinum tip has lost its bond to either the center or ground electrode when they were used in a motor with nitrous.
Thus far the tech's say they have had no problems using Iridium plugs with nitrous.


Can I use Iridium plugs with nitrous injection?

Yes. We double checked with the tech’s on this one, they say, while they have been watching for problems, thus far, there has been no reports of any problems in using iridium plugs with a nitrous system.

Bosch’s Wasted spark system. How this works, is one cylinder is at a certain position BTDC, and when the ECM triggers an ignition coil to spark, current from the coil travels to one spark plug jumping the gap at the spark plug electrodes and igniting the air fuel mixture in the cylinder. The current then travels from the plug to the cylinder head to another plug ground, jumps the plug gap in reverse from the ground to the electrode back to the plug wire leading back to the shared coil pack of those 2 cylinders. This completes the circuit. The first cylinder was fired at a ECM timing BTDC and when firing through the shared cylinder of that coil, the 2nd cylinder will be on the exhaust ****** returning to the coil pack. Since the second cylinder that the current fires through is on the exhaust ****** and not compression the spark is termed “ Wasted “ because it did not create any ignition and no work resulted….. Wasted. This is why it is very important to get the plug wires back in order. This is also the primary reason for not buying gimmick spark plugs. Leave those $25.00 dollar
Gimmick plugs http://www.pulstarplug.com/ on the shelf as these plugs will not work in reverse to ground the shared coil systems, ( wasted spark system).
Plugs chosen for the Land Rover Discovery using the Bosch shared coil system, ( wasted spark system ), must use a plug that works both ways, and cannot be polarized or internal gimmicks placed internally that distinguish polarity of plug. These plugs must work in both directions.

It doesn’t matter what brand you buy, as long as the plug has the heat range that closely matches you engines requirements. If you don’t want to fool around with this Just go and buy the stock plugs for it.



I hope this can n answer a few of the plug questions, Heat range is always the most important.................. Happy Rovering...... chongo

 

[wolf]

Chongo;

excellent info thanks!

Wolf

 

[gpt]

I have a Disco II 2003 with a Bosch Engine. I put Autolite plugs in and now I need to replace the plug wires. The Champion plug technician said the plug to use was a Champion 7318 double platinum. I am going to use Karlyn 7mm plug wires since I can get them locally. Any commentary on the plugs? The original Champion plugs that came with my Disco II RCB11PY??? I believe, I cannot locate anywhere.
Thanks

 

[joey]

The double platinums should work fine... stick with the Champions though.

 

[basstard440]

X2 on the champs. Most people replace there plugs prematurely. Most of the time they just need to be sprayed and regapped. I have a 76 jimmy that has 70k+ miles on the champs but about every 6000 mi I clean them and regap. DONT USE SAND PAPER.

 

[Chongo]

What's brand name got to do with it?

I have a Disco II 2003 with a Bosch Engine. I put Autolite plugs in and now I need to replace the plug wires. The Champion plug technician said the plug to use was a Champion 7318 double platinum. I am going to use Karlyn 7mm plug wires since I can get them locally. Any commentary on the plugs? The original Champion plugs that came with my Disco II RCB11PY??? I believe, I cannot locate anywhere.
Thanks


As long as you adhere to my 5 page write up and the last part written in red about Bosch’s wasted spark system :

Bosch’s Wasted spark system. How this works, is one cylinder is at a certain position BTDC, and when the ECM triggers an ignition coil to spark, current from the coil travels to one spark plug jumping the gap at the spark plug electrodes and igniting the air fuel mixture in the cylinder. The current then travels from the plug to the cylinder head to another plug ground, jumps the plug gap in reverse from the ground to the electrode back to the plug wire leading back to the shared coil pack of those 2 cylinders. This completes the circuit. The first cylinder was fired at a ECM timing BTDC and when firing through the shared cylinder of that coil, the 2nd cylinder will be on the exhaust ****** returning to the coil pack. Since the second cylinder that the current fires through is on the exhaust ****** and not compression the spark is termed “ Wasted “ because it did not create any ignition and no work resulted….. Wasted. This is why it is very important to get the plug wires back in order. This is also the primary reason for not buying gimmick spark plugs. Leave those $25.00 dollar
Gimmick plugs http://www.pulstarplug.com/ on the shelf as these plugs will not work in reverse to ground the shared coil systems, ( wasted spark system).
Plugs chosen for the Land Rover Discovery using the Bosch shared coil system, ( wasted spark system ), must use a plug that works both ways, and cannot be polarized or internal gimmicks placed internally that distinguish polarity of plug. These plugs must work in both directions.

It doesn’t matter what brand you buy, as long as the plug has the heat range that closely matches you engines requirements. If you don’t want to fool around with this Just go and buy the stock plugs for it.

The only difference in plugs is personal choice, as long as the plugs are not polarized then they are ok for use on the Land rover. The land rover needs design specific plugs, not brand name specific plugs. On my wife’s Landover 04 Disco I’m using the Bosch iridium’s with complete success, no problems or issues, and well over 10,000 miles to show for it and since the rings just seated about 1,000 miles ago it couldn’t run sweeter. What I have observed using Denso, NGK, Autolite Champion and Bosch plugs is if it make you sleep better buy the one you like, because I’m not finding any irregularities or differences worth mentioning with any of them. if it makes you sleep better, change the plugs, but there will be no improvement physically possible. I have used my SUN oscilloscope to measure each spark event and each and every time I test plugs, I’m getting similar results no matter the brand name. I like Autolite plugs, there well made, and work well, I use them in my Ford Ranger, and in all of my Chevrolet engines past and present. Changing the plugs out will just cost you money, and there won’t be a benefit in doing so.
Platinum is a conductor and is very dense, and you have to remember that too much conductance is not good for a strong spark. The law of diminishing returns applies here.

Iridium plugs are designed to last longer, iridium itself is a poor conductor, so I’m sure they put an alloy of some metal, or metals in with the iridium to provide the necessary continuity. And resistance in a plug is not always a bad thing, it can make for a stronger spark, and if taken too far, it will stress you coils. The law of diminishing returns applies here too.

So in choosing what car you want to drive, also applies to what brand name plugs, seat covers, wax, air filters etc. etc. etc. And the Autolite plugs you put in your rover, will not fail you if you have the correct heat range plug, and chances are the parts store sold you the champion equivalent in Autolite.

Checking plug wires:

http://www.landroverworld.org/forums/showthread.php?t=12782


What I’d like to know is how much Champion offered Land rover to be their official plug, and since Tata bought and now owns landrover if they will still endorse the same Champion plug?.........
Chongo