Power transmission drive systems have changed over recent years. Dayco’s National Sales Manager, Steve Carolan observed: “The internal combustion engine almost always relies on a mechanically driven primary
drive system.
    
“Until relatively recently, these would have been either via a chain running inside the engine or a belt mounted externally. However, in 2007, Dayco designed and developed an alternative solution that combined the benefits of both a ‘wet’ chain and ‘dry’ belt, to produce the world’s first belt-in-oil (BIO) drive system.”

Advantages
Steve continued: “BIO technology has brought in a true revolution in synchronous transmission systems because developing a solution that enables a drive belt to work inside the confines of the engine has meant that the best of belt and chain technologies have been brought together.
    
“As a result, the previous advantages associated with a chain driven system over an external belt system in terms of the size of the engine, have been mitigated and the more evident advantages of a belt transmission have been maintained. These benefits translate into the ability to reduce the weight of the transmission system and therefore reduce its inertia, which combined with the lower friction properties of a flexible belt, delivers the twin environmental benefits of lower fuel consumption and reduced emissions.
    
“BIO belts are also typically not as wide as dry belts because the need to dissipate the heat that naturally builds up as a result of friction between the belt and the pulleys/tensioners, is counteracted by the fact that the oil both reduces the level of friction between these components and cools the belt. Dayco BIO applications also benefit from the company’s unique use of PTFE on the teeth of its HT belts, which further reduces friction and means that they have a greater load capacity and provide a longer service life.
    
“However, perhaps the most significant contribution to these savings is the fact that, unlike a chain, a timing belt, whether located on the wet or dry side of the engine, cannot stretch, which prevents the engine from undergoing phase variations due to elongation and therefore actively helps to avoid increased pollution caused by incorrect valve timing.”

Boundaries
Carmakers are being strongly encouraged through worldwide legislation to reduce exhaust emissions and increase fuel efficiency. “Looking at their mainstream power plants,” said Steve, “Ford for example, has made the decision to deploy a range of high performance, small capacity petrol and diesel engines to address the emission/consumption challenge.
    
“Ford’s EcoBoost family of turbocharged, direct injection petrol engines are designed to deliver levels of power and torque normally associated with larger capacity engines, while at the same time achieving 20% better fuel efficiency and 15% lower emissions. Integral to the EcoBoost design is the revolutionary BIO timing drive system developed by Dayco.”
    
Steve added: “These original equipment developments are naturally reflected in Dayco’s aftermarket programme, which allows factors to supply independent workshops with these solutions to enable them to offer their customers a like-for-like replacement that provides them with an alternative to the franchised dealer.”

Profit
As they change, clutch systems have a growing reputation for being complicated. “Some workshops avoid clutch work,” observed Schaeffler Marketing Communications Manager Jeff Earl, “preferring instead to send it to a ‘specialist’; however, by following a few simple precautions, every workshop can avoid turning work down and start turning a profit.
    
“Supplying car parts is becoming increasingly difficult, especially genuine parts from OE suppliers. Finding additional basic vehicle details – preferably directly from the car – will help the motor factor supply the correct part first time. Schaeffler’s REPXPERT online workshop portal is a perfect place to start.
    
“Technicians can also access REPXPERT direct from their mobile device, with extra functionality such as a barcode scanner that will take you straight to all of the technical documents for the parts you have ordered.”

Equipment
“There is not a great deal of specialised equipment required, but a few essentials will make the job easier; a two-post ramp and a working transmission jack – or two if working on larger vehicles preferably with a tilting head for a trouble-free refit.
    
“A universal alignment tool will also make gearbox installation easier and prevent damage to the new clutch. While it is essential to use a special tool to fit self-adjusting clutches, Schaeffler’s SAC tool has added value, as it can be used during any clutch installation to help ensure correct fitment, whilst also including special alignment tools to suit all the latest BMW applications.
  
“A DMF can be checked for wear prior to removal by using a LuK DMF tool in conjunction with the DMF CheckPoint function in the REPXPERT app. If the DMF does need replacing, then the app also informs the technician if new bolts are required and what torque values to use.”

The right parts
“Once the parts have arrived and the gearbox has been removed,” continued Jeff, “it’s always worth conducting some basic comparisons.
    
“Sliding the drive plate back and forth to distribute a small amount of grease is a good check that the splines are correct – not forgetting to wipe off any excess grease afterwards.
    
“On many LuK clutches ‘Getriebe Seite’ may be seen, which is German for ‘Gearbox Side’, while ‘Schwungrad’ is translated to ‘Flywheel’.
    
If something different is identified – or no direction is given – technicians should carefully check the installation instructions, to avoid problems caused by fitting the drive plate incorrectly.
    
“It is always worth checking the reluctor/sensor ring on the back of a DMF. Even if it’s from a different manufacturer it should still have the same number of teeth and they should be undamaged. OE suppliers, such as Schaeffler, will replace transit damaged goods – if it has been spotted before fitment.
    
“A modern plastic CSC can obviously look different, especially if the original was metal, but it should have the same number of fixings and the pipe position should be similar. It may sound simple, but technicians should always read the instruction sheet inside the CSC box. It may contain critical information, such as how to find and discard a redundant pipe seal on Vauxhall applications, and some Ford instructions explain that the O-ring should be replaced by sealant.
    
“Worn or seized cross shaft bushes need to be rectified; bent or damaged forks need to be replaced; technicians need to always replace the ball pivot on BMW applications and check the others; repair leaking gearbox seals and, finally, reset or replace all self-adjusting cables.”

Finishing touches
Jeff concluded: “Technicians should never grease plastic release bearings. On most pull-type clutches, technicians should fit the release bearing to the gearbox, and locate it to the clutch cover after fitting the gearbox. They need to be extremely careful when inserting the gearbox; swinging up and down on the back of a gearbox, to fit it to a poorly aligned clutch, will most probably cause damage and judder.”