March 2020

JULY 2017 AFTERMARKET 3 www.aftermarketonline.net MARCH 2020 AFTER RKET 45 Spark plug Q&A DENSO are both an OE manufacturer and supplier of spark plugs, so are regularly faced with questions around the devices. Here, Assistant Manager Aftermarket UK & IE, Mike Sadler answers some of these questions. Q: Which is the right spark plug? “There are many factors to consider, such as dimensions, projection and heat range. The easiest way to identify the correct spark plug is by checking out the DENSO E-Catalogue. This resource allows users to locate the appropriate DENSO parts, based on make and model information or by cross-referencing.” Q: Which spark plug should be used for liquid petroleum gas (LPG) applications? “LPG and compressed natural gas (CNG) engines require a higher performance from a spark plug than petrol engines. The DENSO Twin Top (TT) range, for example, offers an upgrade to meet LPG/CNG requirements.” Q: Should the electrode gap be modified? “DENSO’s spark plugs are manufactured with a pre-set gap; however, with nickel plugs, especially for motorcycles, the gap may need adjusting. In that case, technicians should always use a special spark plug gapping tool to alter the opening. Technicians should never change the gap on platinum, iridium or TT spark plugs, though, as doing so may damage the fine electrodes.” Q: How often should spark plugs be replaced? “Generally, the replacement interval is confirmed by the vehicle manufacturer – DENSO’s spark plugs mirror that advice. When upgrading spark plugs, though, the interval may alter. Driving on LPG or CNG will shorten the life by as much as 30%, and it is recommended that spark plugs are checked regularly and should be replaced when they’re ‘fouled’, which is when a plug has become covered in a substance, like oil, fuel or carbon, or it has become blistered from running at too hot a temperature.” Q: Should grease be applied to the spark plug thread? “DENSO recommends not using a thread lubricant because if grease, for example, is coated on the thread itself, the spark plug is likely to be too tight when applying the recommended torque, which can cause damage to the spark plug. Consequently, vibrations may cause the plug to become loose. Only in a few exceptional cases, such as LPG-powered forklifts, should a small amount of grease be needed, and in that case, the spark plug will be pre-lubricated.” Q: Can a multi-ground spark plug be replaced by a single-ground spark plug? “A multi-ground electrode is preferred by some engine manufacturers and VMs because of the extended lifetime of the additional ground electrodes. Extending a spark plug’s service interval, without the use of precious metals, is a very cost-effective solution. Multi-ground spark plugs are designed specifically for long life rather than performance, but replacing a multi-ground spark plug with a single ground spark plug will improve performance, at the sacrifice of reduce service life. Upgrading a multi-ground electrode spark plug to a long-life iridium spark plug, like the DENSO Iridium TT, will combine both performance and durability.” Ignition leads Meanwhile, NGK recently launched a new range of ignition lead sets in the UK. The range comprises more than 40 part numbers including copper core, carbon and inductive resistor types. Mark Hallam, Marketing Manager, NGK Spark Plugs, said: “NGK is always looking to further improve its product offering to customers and was delighted to introduce this new range of ignition lead sets with the technology that meets the OE standards of car manufacturers and further consolidates its position as the leading ignition specialist in the UK market-place. “NGK has long been renowned as a supplier of OE spark plugs and glow plugs, while also increasingly adding to its NTK range of sensors, and this new ignition product range has already proved popular with our customers who know and trust the components we put our name to.” Mark added: “The launch followed hard on the heels of NGK’s introduction earlier in the year of a new range of premium NTK camshaft and crankshaft sensors, also known as engine speed and position sensors. The sensors – comprising more than 200 UK-specific part numbers with excellent UK vehicle parc coverage – opened up further OE replacement opportunities for aftermarket customers and followed the introduction of 20 new wide band Lambda sensors – commonly referred to as ‘5-wire’ Lambda sensors.”