January 6, 2003

No it’s not the psychic hotline, it’s technology of the Winston Cup series.

Ever wonder how the teams of the Winston Cup series maintain those big beast 770 HP engines while at the track? It’s all about being able to read the spark plugs and interoperate what you see with the use of a scope similar to what a doctor uses to look into your ears.

Although you may not consider the lowly spark plug as a huge factor to the winning team on any given Sunday, its presence and reliability is counted on time after time.

The idea of the spark plug is to provide a seal from the combustion chamber. Oh sure, that’s the easy part, conducting the spark and providing a gap for the kernelled spark to jump across gets a little more complex.

Over the years a vast amount of technology has gone into the making of a better spark plug for the high compression engines in the Winston Cup series. Understanding how an engine is performing and, tuning the air flow mix is a process that employs some of the greatest gurus of all time in the garage area.

When you see a car jet across the finish line and suddenly cut the motor while at full speed after a qualifying session the driver is archiving the engines history on the spark plugs. This process is referred to as “cut clean” While back at the garage area, the spark plugs will be carefully removed and placed into a holder of sorts. This is the point at which the plug guru is called upon to give the reading.

Earl Parker II comes to mind when you start discussing spark plug tuning technique. Earl is a race engineer for the Champion Spark Plug Company and, says “I can read the plugs, track the weather and then use that combination of information to advise the engine tuner to make adjustments in ignition timing, air fuel ratio and spark plug heat range.” Jack Roush is another person that you will see having a look at the spark plugs. Jack still calls the shots on what moves to make in carburetion for his race teams.

J-Plug

When we think about current technology in the Winston Cup series we must realize that times have changed. It used to be that there was but one type of spark plug used for practice as well as the race event. Changes in plug design have led to advancement in technology. In the past a plug that had a common ground wire formed in the shape of a “J” was used, this is the type of designed plug that you have seen many times and is common for the most part.

Currently in the Winston Cup series we see a spark plug that is known as an Angled “A” Gap. This design offers an angled ground electrode that is shorter than the “J” and provides additional exposed gap thus a greater bang for the buck when dealing with the high powered engines of today.

For the actual race event after all air fuel mix tuning has been performed the teams will go with an Angled “A” Gap but with a total of four electrodes in most cases. It would be very extensive to attempt to read this type of plug thus a single electrode plug is utilized during the tuning process.

A-Gap

The installation of the “A” Gap plug into the cylinder head is also a procedure whereas the term “indexing” is brought into the equation. Indexing relates to the process of getting the gap area on the plug to face the center of the cylinder and slightly angle it toward the exhaust valve. This process involves the use of indexing washers that for the most part come in a set of three different thicknesses. Placing a scribed mark on the outer portion of the plug in the location equal to the electrode lets you realize when the plug is located at a desired position in the cylinder head. The use of the color coded, precision stamped, copper washers allow you adjustment for a perfect fit.

So now we have our indexed plug properly installed as to allow the kernel of spark to emit toward the desired area in the combustion chamber.

Winston Cup teams will use what is termed a “cold plug.”

Heat range of spark plugs can be confusing but for the sake of the Winston Cup series we must realize that colder ranges are utilized in engines with increased cylinder pressures. A rule of thumb to draw on is the fact that a cold plug is for a hot engine with high horsepower and, a hot plug will be found in a cold engine with lower horse power. The range of plugs from hot to cold is adjusted by the length of the insulator nose with a hot plug being the longest of that variety. Heat range selection of spark plugs will vary from track to track during the season and, the reading of the plugs may point to changes on any given day.

Plug tip temperature in most cases runs a range of 850F to somewhere around 1550F. Remember now that we are dealing with a cold plug in the Winston cup series so, our temperature may be toward the lower portion of that scale. When using identical spark plugs, consideration is given to how much combusted heat can be removed from the chamber in one stroke thus, a heat change is considered in 50F to 70F increments.

So, readings taken from indexed spark plugs become vital information for all teams during testing and practice. NASCAR does not allow for the specific use of data acquisition systems. As long as that continues we will see spark plug gurus giving their opinions as rendered from readings. Oh, sure there are digital gizmos that can do this job with no readings but analog is where it’s at in the Winston Cup series

Champion Spark plugs found their way to victory lane 16 times during the 2002 Winston cup series. That variety of plug and technology is used by teams such as DEI, Roush Racing and, Joe Gibbs whom won the Championship with Champion under the hood. Bosch, NGK, Autolite, Delphi and, AC also manufacture and, supply spark plugs for the Winston cup series with a varying degree in styles and technology.

So, the next time you see the Cat in the Hat looking down from a magnifying glass at a box being held in his hand remember that he isn’t counting change for the coffee machine. He is giving one of the most detailed opinions in NASCAR today.

You can contact Joe at: Insider Racing News