Magnecor's gallery of "faulty" wires

Magnecor receives many used ignition wires sent in for evaluation from both the auto industry and consumers. We receive original equipment and aftermarket wires, and also our own wires that have allegedly "failed" for various reasons. Some vehicles will prematurely destroy any brand ignition wires unless proper preventive maintenance is performed regularly to prevent engine and other problems causing damage to the ignition wires. As those vehicles age, virtually everything in the engine bay is affected by corrosion and oil leaks, and problems that cause damage to ignition wires will occur more often, and for this reason, even more preventive maintenance will be required. We have prepared technical bulletins to alert consumers of the vehicles most prone to problems that cause ignition wire failure, as well as other useful information (which is worth reading, even if you don't own any of the vehicles in question).

Often, we receive wires that have been declared "bad" or "faulty" by automotive technicians and consumers that have obviously failed for reasons beyond the control of an ignition wire manufacturer. On many vehicles, ignition wires are located where excessive heat (usually on modified engines with poorly designed headers), vibration, leaking oil and water retention in deep un-drained spark plug holes can cause all sorts of problems for ignition wires if the engine is not serviced properly and regularly. Also, it never ceases to amaze us how many wires not fitted correctly are declared "faulty". Of course, as long as vehicle manufacturers design engines where it's impossible to easily reach (or even see) the spark plugs, there will always be times when spark plug wires are not fitted properly.

In recent years, vehicle manufacturers using "multi-valve" engines with spark plugs located in deep un-drained holes in the cylinder head have gone out of their way to create spark plug wires using complicated extended connectors on the spark plug end which have little or no hope of surviving arcing caused by water and oil in the spark plug holes without constant vigilance on the part of the vehicle owner. With some vehicles, it can cost an owner hundreds of dollars in labor to remove and replace components (such as intake manifolds) just to get to the spark plug holes. For this reason, it's understandable some vehicle owners won't be as vigilant as others, particularly as there's never a warning from vehicle manufacturers as to problems caused by poor design.

Another developing problem is premature spark plug failure. Modern engines use small size spark plugs, and engines boosted with turbocharging and supercharging place additional strain on these small spark plugs, particularly when gaps are enlarged by erosion or adjustment. Both vehicle and spark plug manufacturers would like you to think spark plugs last from 30,000 to 100,000 miles, and mostly they do. Unfortunately, a surprising number don't, and premature failure is usually caused by either the porcelain insulator cracking or developing leaks around the seals. Inevitably, the spark plug wires are initially blamed for the resulting engine miss-fire, or combustion gases leaking inside the wire spark plug connectors which pops them off the spark plugs, or the galvanic binding of terminals onto spark plug tops (dissimilar metals) caused by corrosive combustion gas leaking past the top of the spark plug porcelain seal.

  1. Extreme moisture problem (thumbnail version)
    Extreme moisture problem (with 45KB image)

  2. Spark plug boot is changing color (thumbnail version)
    Spark plug boot is changing color (with 33KB image)

  3. "The spark plug wire is melting!" (battery acid) (thumbnail version)
    "The spark plug wire is melting!" (battery acid) (with 55KB image)

  4. Spark plug boot is cut (thumbnail version)
    Spark plug boot is cut (with 33KB image)

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