Diagnosing a high performance modified engine is a hard work and it is plenty of secrets

A very common way to diagnose and tune-up a modified or racing engine is by looking the spark plug firing tips because its appearance can reveal if your engine has a problem that need correcting. But you need to be aware that the same spark plug firing tips appearance can have different root causes:

A) Mixture or timing misadjustment or other possible mechanical troubles.

B) High performance modifications that increase the horse-power level, augmenting therefore the combustion chambers temperature and stress at high RPM.

C) Colder racing spark plugs fouling at idle, stop and go, and lower speeds.

Unfortunately, for each spark plug firing tip appearance, the traditional spark plug troubleshooting charts only are considering as possible trouble causes the first list A.

But in high performance modified engines and racing applications, the list B is usually the main cause of the higher temperatures in the combustion chambers that generates overheating, pre-ignition and detonation; and the list C is the main cause of fouled spark plugs that generates misfiring, hard starting, black smoke and great loose of power.

In spite of that fact, carefully review of almost all the troubleshooting charts, reveals that the causes of the B and C lists are not included, or at least mentioned. However when talking on the high performance field, these causes are with extreme frequency the main guilty of most of the troublesome spark plug firing tip appearance.

As result of this lack of information, never was sufficiently clear that the undesirable spark plug firing tip might be attributable to an inappropriate spark plugs heat range. Either never was mentioned strongly enough the transcendent importance that have to customize the spark plugs heat range, so it was never taken into account.

Forasmuch it should not surprise that even experienced engine builders, modifiers and tuners often confuse an overheated spark plug caused by the new level of power at high RPM, with a lean mixture trouble, because the appearances of its firing tip look exactly the same; making wrong diagnostics, and enriching the mixture, instead of customize the heat range to the engine's power.

And worst, when the heat excess level provokes pre-ignition or detonation (which is very frequent due to the high levels of demands that the racing engines are submitted) most of the times the traditional troubleshooting charts are guiding them erroneously to believe that their engines are having some mechanical troubles and therefore they are engaging unnecessarily in repair nonexistent mechanical problems, like cooling system failure: or to suppose that it is owed to a mixture or timing misadjustment, consequently enriching the mixture and/or retarding the ignition timing, arriving inclusive to decrease the boost pressure, the nitrous flow, the compression ratio, etc. losing by this way tons of power, instead of the unique right, simplest, fastest and cheapest solution that is to customizing the spark plug heat range to the huge power, stress and heat achieved at high RPM.

Due to the same absence of information, they can not either distinguish when the cold racing spark plugs are fouling at idle, stop and go, and lower speeds, from when has a rich mixture, because both have the same carbon fouled firing tips appearance; and what is still worst, they can not either distinguish when the colder racing spark plugs for heavily modified engines are fouling at idle, stop and go, and lower speeds, from when the engines has worn-out piston rings and cylinders, because both have the same oil fouled firing tips appearance.

Those wrong diagnostics are leading them to wrong solutions: trying to adjust unnecessarily the air-fuel mixture when they see carbon fouled spark plugs, and being bottled without need in overhauling the engine to repair mechanical troubles that do not exist, when they see oil fouled spark plugs, instead of avoiding idle and lower speeds in engines built for run at high RPM, or to customize the spark plug heat range for these type of show off usage.

Also when the traditional spark plug troubleshooting charts mention "wrong heat range" or "check for the correct heat range", because it is not enough clear, a great majority of they are quite familiarized with the concept that "wrong heat range" only could be a spark plug different than the stock or the suggested by the manufacturers, ignoring that they should switch the spark plug's heat range.
And, as if was not sufficient with this confusion with the information, until very short time did not exist method neither tool to perform the important task of customize the heat range of the sparkplug, according to any specific high performance modification level, so, the election of the aftermarket sparkplug that best works at any RPM load or stress, was left to the intuition, experience and the criterion of each technician, who only had the unfriendly guesswork of never-ending trial and error proofs, testing different spark plug sets, with inexact and risky results.

But the racing field is no place for mistakes.

Is for that reason that the traditional troubleshooting charts are not the most adequate guide to properly and accurately diagnosing your expensive high performance modified or racing engine, risking you to lose your engine and that is still worse, to lose the race.

What is then the right way to correctly diagnose the spark plugs in the high performance field?
Be sure that, if you are not having real mechanic problems, you must check the heat range of the installed spark plugs, and select the replacement with the colder heat range better suited to your exactly high performance modification level.

Is it a hard work? It depends. If you are using the right tool, that allows you to see, confirm, verify, select, and choose the exact heat range you must install in your high performance modified engine, it is a piece of cake!

Of course if not..... it could be unending, unfriendly, blind and risky guesswork.

You decide!

By Elena Maria Db Orsos