RWD Newsletter September 2009
Page 3: Spark Plug Wires, Spark Plugs

Worn spark plug wires can be tough to diagnose as they may function normally upon inspection, but as cylinder pressure rises under load the resistance at the spark plug goes way up. A faulty wire allows spark energy to "leak" out of the wire resulting in a miss and reduced output. If the wires are brittle and difficult to bend, they are in need of replacement. If you have access to a volt ohm meter, you can also test the resistance of each wire. A good wire should have 1500 to 3500 ohms resistance. Replace any wires with resistance greater than 30,000 ohms which indicates that the internal conductor is failing.

When handling spark plug wires, never bend the wires at sharp angles as this can cause an internal break in the wire. When removing spark plug wires, do not pull on the wire itself. This is a common mistake that can ruin the wire by breaking the internal connection to the spark plug connector. Pull only on the boot by hand or with a spark plug wire removal tool. Spark plug wires typically last 30 - 50K miles.

Our custom spark plug wires are made with a high quality 8mm silicone jacket and feature a spiral wound core for maximum electrical efficiency. Each wire set is custom designed for each application covering over 40 years of Volvo models. Engineered to meet and surpass OEM quality, our wire sets include factory style metal end connectors (where applicable). Each wire set includes spark plug and coil wires as well as dielectric grease used on the plug boots for easy removal at tune-up time.

A properly tuned ignition system is one of the most important factors of any engine. It will keep your engine running smoothly, economically and will deliver the most power. The increased heat under the hood may lead to premature degradation of the ignition wires. These wires are made by the original equipment supplier to Volvo so you are assured of the best quality in replacement wires.

The first suspect in a poor-performing engine always seems to be the plugs. On overhead cam engines one should expect about 30k miles but, as these are getting older, they are wearing out sooner too. Contaminants such as oil and incorrect fuel mix will shorten the life of a plug dramatically. We have been using and selling NGK spark plugs since the seventies because they’re the leaders in copper core technology. Copper is a great conductor of electricity and heat, so copper spark plugs perform well under all extremes and have a large conductor tip for maximum spark area.

Denso Iridium plugs are serious power and performance for even the most serious of performance minded customers. Pure Iridium has a melting point of almost 700ºC higher than that of platinum and better withstands overheating, detonation, and oxidation wear. Denso Iridium plugs are combined with Rhodium for superior heat resistance and response. With high-power and high-heat turbo engines, you need all the help you can battling heat and detonation. Bring in a ringer with Denso Iridium plugs.