September 2019

A s well as producing engine products and drive systems, Dayco also manufactures OE torsional vibration dampers for a number of VMs worldwide. The company has now made the range available to the aftermarket. “Modern powerplants are highly engineered to deliver the optimum combination of power and torque, alongside fuel efficiency and minimal exhaust emissions,” says Dayco’s National Sales Manager Steve Carolan. “This objective often comes at the cost of high levels of engine vibration, which is generally intensified by the significant pressures present in the engine’s combustion chambers, an occurrence especially prevalent with diesel units. “This vibration is transmitted through the crankshaft and therefore has a significant impact on the engine’s power transmission drive systems.” To reduce this problem, Dayco engineers have developed a range of damper pulleys, with the prefix DPV. “Generally installed directly to the crankshaft, observes Steve, “the damper reduces the circular vibrations that cause the primary problem, decreasing wear on many of the engine’s components. Naturally, the front end auxiliary drive (FEAD) system is a principal beneficiary, which increases the durability of the entire powerplant, but they also improve comfort for the vehicle’s occupants.” Three types There are three types of damper that, depending on the application, are generally installed: The simple, double and decoupler. “The simple damper is integrated within the FEAD system,” explains Steve. “Its single rubber element provides sufficient vibration reduction for applications with standard noise, vibration and harshness (NVH) requirements. “The double damper encompasses two rubber elements within its metal parts, which are designed to absorb vibration at different frequencies, and is for use in applications that generate high power and increased vibration, such as modern diesel engines. “Although the decoupler damper still incorporates a rubber ring, the damping function is carried out through metal springs, as opposed to solely relying on its rubber element. It is used on the latest generation engines with greater power and enables the FEAD system to cope with high mileage and adverse conditions, particularly for applications that feature belt start generator (BSG) function for their Stop/Start systems.” Damper Replacement Commenting on replacement, Steve says: “Dampers should be checked for signs of wear, such as abnormal noises, unpleasant vibrations or even steering oscillations, at every 40,000 mile interval or when replacing the auxiliary belt. However, as a matter of course and irrespective of the signs, Dayco suggests they are changed every time the timing belt is renewed.” “In order to check the damper correctly, it needs to be removed from the engine because the back, as well as the front needs to be examined to fully assess its condition. In addition, whether it needs to be replaced or not, if its fixing bolts are designed to stretch on initial fitment, these must be changed, as they will no longer meet their design tolerances if reused.” Steve adds: “Dayco DPVs are produced in the same facilities, to identical standards, whether the damper is destined for OE or aftermarket. Each damper in the range that also requires its bolts to be replaced, comes complete with the correct specification bolts.” For more information visit: www.dayco.com 54 AFTERMARKET SEPTEMBER 2019 TECHNICAL www.aftermarketonline.net DAYCO: OE DAMPER PULLEYS Dayco has launched a range of OE damper pulleys for the aftermarket OE Damper pulleys from Dayco