Category Archives: Engine Parts & Timing Belts

Best practice for Timing Belts, Tensioners and Tools

Best practice for Timing Belts, Tensioners and Tools

Gates explains how comebacks and common installation errors are being reduced with a focus on appropriate tools and specific fitting instructions.


In the latest series of Gates technical workshops, the Gates Technical Training and Support Team is providing mechanics around the UK with logical explanations for premature timing belt failures often considered as ‘mysterious’.

Synchronous Belt Drive Systems (SBDS) from two engines with different ‘automatic tensioners’, different belt tension setting procedures and different sets of precision tools have been catching the attention of mechanics on a regular basis.

The engines involved are:

■ Renault 2.2dCi, 2.5dCi engines –2000 onwards

■ Ford 1.8 TD, TDCi, TDDi (all eight-valves)

Technicians sometimes compromise the job by failing to allow engines to return to ambient temperatures. Another common error is to assume that automatic tensioners require no specific tension setting procedures. Without these procedures, automatic tensioners cannot perform effectively and efficiently.

Belt design and construction

Ahead of discussions about the specific installation and belt tension-setting issues, it is worthwhile providing some context by briefly discussing the design and construction of all Gates belts.

The internal ‘s’- and ‘z’-twisted tensile cords contribute not just strength, but also balance and deliver stabilising qualities to the synchronous belt. These combine to help keep the belt centralised on the pulley. Precise belt tension is the key to retaining the central position. It is this that ensures efficient overall performance of the SBDS.

Renault 2.2-2.5 tensioner and setup

Fitted to Renault Espace, Laguna, Master and Traffic models, these engines are also a fixture of some Vauxhall and Nissan ranges. In each case, precise timing belt tension is established through a two-stage process. A Camshaft Locking Tool is required (GAT 4760B) to set the precise tensioner position. With the tool in place, the position is set by means of a lever arm on the locking tool itself. When the lever arm is level with the top of the locking tool, high tension has been achieved.

Note: This is only the desired initial tensioner position.

The Camshaft Locking Tool is then removed and the engine rotated manually, through a specified number of revolutions. The Camshaft Locking Tool is now replaced and the correct installation tension is set by aligning the raised edge of the lever arm. It must be level with the top of the tool. Both stages are essential to the procedure. Completion of both stages is the only way that installation tension can be achieved.

Ford 1.8 TD, TDCi, TDDi (all eight-valves)

Frequently installed on models such as the Ford Galaxy from 2009 and the Ford Mondeo from 2012, advice from the Gates Technical Training and Support Team is that at commencement, the engine must be atambient temperature. Locking and setting tools from the Gates Professional Tools Range (GAT 4830 and GAT 4304) are also recommended for the job.

Vital steps in the fitting procedure include locking the crankshaft and flywheel, locking the camshaft (rear of the engine) and loosening the camshaft sprocket while holding it in place so it’s free to rotate on the taper. This is important because otherwise the top span of the belt cannot be tensioned.

Other important steps include:

■ Rotating tensioner anticlockwise

■ Lining up indicator with the centre of the slot

■ Bolt torque = 50Nm

■ Rotating engine manually (through almost six revolutions)

Re-inserting the crankshaft pin, then rotating the engine to Top Dead Centre completes the automatic tension setting procedure – as long as the indicator remains in the centre of the slot.

Safely Replacing TVD Bolts

Safely Replacing TVD Bolts

Trying to decide whether it’s safe to re-use a Torsional Vibration Damper (TVD) bolt is not straightforward. For a start, not all bolts are the same, not all TVDs are mounted in the same way, and they do not all use the same number of bolts. Making the right decision is crucial. Gates offers a helping hand.

A wrong decision could cause a premature drive system failure that will lead to comebacks. In the worst-case scenario, debris from the Accessory Belt Drive System (ABDS) could compromise the timing belt and cause catastrophic engine damage.

Function

TVDs, or damper pulleys, absorb vibrations. Essentially, these vibrations arise from the use of more and more lightweight components to reduce overall vehicle weight and reduce carbon footprints. The additional power from increasingly powerful compact engines creates conflict. Greater power adds strain on lightweight components – causing the vibrations.

The pulleys achieve this thanks to a rubber damping agent, designed to absorb most of the vibrations. That’s one reason why Gates encourages mechanics to install ABDS belt kits that include new TVDs.

The benefits of replacing the TVD at the same time as the belt include:

■ Prevention of failure of the crankshaft by fatigue
■ Decreased wear and tear on the belt, tensioner and other components in the driven assembly
■ Improvement in noise, vibration and harshness (NVH) characteristics. This increases the level of comfort for drivers and their passengers

Installing a TVD correctly protects all the components in the drive system and extends their operational lifetimes.

Complex decision

TVDs are ‘secured’ or ‘fixed’ in one of four alternative ways. These may involve:

  • A single central crankshaft bolt
  • Multiple crankshaft bolts
  • Multiple installation bolts
  • A combination of crankshaft bolts and installation bolts

There are additional complications to consider. For example, bolts that encounter elastic, temporary deformation during fixation can be re-used. This is because they regain their original form after the stress is relieved. Bolts that encounter plastic, permanent deformation during the installation of the TVD, cannot be used to install a new damper, as they might break. Moreover, some TVD bolts always require replacement. Others can be re-used without any issues. If there is more than one bolt, the crucial decision is multiplied.

Easy solution

Replacing all the bolts all the time is one solution, but throwing away a good re- useable bolt negates some of the vehicle manufacturer’s initial efforts to reduce the overall environmental impact. The sensible solution is to always replace the bolts that must always be replaced. Recycling re- usable bolts safely saves resources and respects the environment.

Gates has updated its entire DriveAlign TVD range. Each red Gates box includes the TVD and just the bolts that must always be replaced. In other words, as an installer, you get everything required to complete the job with premium parts, technical clarity and peace of mind. It’s an environmentally respectful job well done – every time.

Timing Belt Replacement on Mk7 Golf 1.0 TSI

Out of Touch, Out of Time – Tips on Timing Belt Replacement on the Mk7 Golf 1.0 TSI.

In this article, our friends over at Gates explain to us why the VW 1.0TSI range has it’s own unique challenges.

VW added the 1L three-cylinder petrol engine to its flagship Golf range in 2015. It’s also a feature of many other VW, Audi, Seat and Skoda models.

The new engine featured non-round pulleys in the Synchronous Belt Drive System (SBDS). The combination helped make significant contributions towards lower overall weights, quieter engines, reduced CO2 emissions and improved driving dynamics.

Now that the new car warranty periods have started to expire, car owners are seeking fresh providers of service and general maintenance work. This means these models are beginning to roll through the doors of many independent garages.

Replacing the timing belts presents new challenges for drive systems specialists. For many, it’s a first encounter with non-round pulleys. For all, it’s a procedure that must not be attempted without the correct set of tools.

Tools required and points to note

As the drive system positioning of the non- round pulleys is extremely important, specific tools are vital to the success of the belt replacement procedure. The Gates timing tool kit (GAT 5140) is required to complete this job correctly. An appropriate camshaft pulley holding tool is required (for example, GAT4844). A crankshaft holding tool is also essential (for example, GAT 5169). When replacing the timing belt, it is good workshop practice to replace the associated metal components at the same time. Gates PowerGrip Kits include belts as well as any appropriate tensioners and idlers.

The water pump is driven by a separate small timing belt without a tensioner. Gates supplies separate belt kits for both the timing belt and the water pump. Note that not all timing belts have a synchronising function.

Twelve-step procedure

1. The first step is to put the engine’s first cylinder at top dead centre (TDC), then lock the crankshaft (locking pin on the side) and the camshaft at the rear.

2. Holding the pulleys in place, loosen the camshaft pulley bolts (right bolt behind plug). Loosen the exhaust camshaft pulley (left) from the conical axle; loosen the belt tensioner pulley bolt while holding the tensioner in place; rotate anti-clockwise (till the retaining lug is situated at the bottom of the slotted hole).

3. Remove the belt.

4. Replace the tensioner and the idler and fit the camshaft pulley locking tool. This will secure the location of the two camshaft pulleys. It is important that they remain in the exact position at which their non-roundness will work to the advantage of the engine (otherwise they will increase belt tension fluctuation rather than reduce it). Note that the dots on both pulleys (at +/- 3 and 9 o’clock (and 12 o’clock) will not line up perfectly.

5. Install the new belt (crankshaft, tensioner, camshafts and idler). Ensure that it is taut on the left side.

6. Remove the little camshaft pulley locking tool. Rotate the tensioner clockwise. The pointer must be 10mm past the notch (window).

7. Bring the pointer back to the middle of the window and torque the bolt to 25Nm.

8. Holding the camshaft bolts in place, lock them to 50Nm. Holding the bolts is a crucial part of the procedure. Install the crankshaft Micro-V pulley. Set a torque of 150Nm and then turn it through another 180 ̊ using the crankshaft holding tool.

9. Remove the locking tools. Rotate the engine, by hand, through two complete revolutions to TDC. Reinstall the locking tools (crankshaft and rear camshaft).

10. If reinstalling the tools proves impossible, restart the procedure from step 1.

11. If this does prove feasible, hold the camshaft sprockets in place and torque a further 90 ̊.

12. Bring the tensioner pointer back to the middle of the notch (25Nm).

Non-round benefits

The non-round pulley design is, initially, difficult to spot. It only becomes obvious when slowly rotating the loosened pulley with your finger or rolling it across a flat surface. The design is vital to the ‘belt dynamic tension optimisation’ process, which is the key to the high performance and low emission qualities of this particular three- cylinder engine. During the intake or suction phase, the piston is moving down, while at the next stroke (compression), it compresses the mixture of air and fuel.

This is followed by strokes three and four – combustion and exhaust. These different strokes cause significant belt tension variation throughout the combustion cycle. This tension variation is countered by means of the non-round pulley design, which delivers a defined amplitude and phasing. The result: optimised belt tension.

Dealing with Oil Leaks

Dealing with Turbo Oil Leaks

In this article, we take a look at oil leaks related to your turbo, and what you can do to prevent them.

What are oil leaks?

Oil leaks can be caused by a variety of factors – the main factor being incorrect pressure within the compressor and turbine housings. Oil leaks can cause catastrophic damage to the bearing systems and occur within seconds of the turbocharger commencing operation. When a turbocharger is installed correctly, it should NOT leak oil. However, there can be cases where oil leaks occur. The table on the right highlights some of the main causes and signs of oil leaks.

Example of correct pressures:

PLEASE NOTE:

An oil leak can also occur when engines are running on idle. The pressure within the housings is lower, which in turn can lead to a vacuum being created, causing the oil to leak into the turbine housing. Once the engine starts to run at normal speeds, the pressures will be restored and the leaks will stop.


Examples of how oil leaks can occur:

PLEASE NOTE:

Oil leaks can occur on VSR (high speed) balancing machines as the ambient pressures required to create the seal are not present as no housings are used. This can then force out oil from both the compressor end and turbine end, giving the impression of a leak. This is unlikely to occur when the replacement turbo is fitted to the engine.

‘Piston ring blow by’ and ‘crank case blow by’ cause the same effect, they increase the pressure in the crank case. This affects the oil flow to the turbo at the correct rate needed and acts as a restriction to the oil feed pipe, causing the turbo to leak oil in either the turbine end or compressor end.

Preventing future oil leaks:

■ Ensure air and oil drain systems are clear from blockages or restrictions
■ Check the exhaust system to make sure there are no leaks present
■ Do not use silicone on oil gaskets as it can easily become detached and block oil passages Ensure DPF and Catalytic converter are free of blockages
■ Use the correct gaskets and o-rings
■ Only use the correct standard of turbine housings and compressor housings
■ Check for correct oil levels and pressure


WATER PUMP REPLACEMENT: THE DO’S AND DON’TS

Water Pump Replacement: The Do’s and Don’ts

Replacing a water pump requires a fair amount of technical expertise. Are you planning on installing a new water pump? These do’s and don’ts will help you avoid 9 common mistakes.

1. Don’t Worry if the New Water Pump Looks a Little Different from the Old One

It is possible that there’s a visual difference between the new water pump you’re about to install and the old pump you have just removed. Perhaps the new one has a metal paddle wheel while the old one had a plastic paddle wheel, or perhaps its shape is somewhat different. Don’t worry about these minor differences; all that matters is the position of the water pump pulley. It should be at the same height as in the old pump because – if the belt starts rubbing against the pulley – it will become frayed. To check if you’re good to go, simply put both water pumps on your workbench, face down (i.e. with the side that touches the engine), and compare the position of the pulley.

2. Do Flush the Cooling System

Not flushing the cooling system is a common mistake that could cost you dearly. After all, the old coolant is likely to be contaminated, and its impurities could settle where the dynamic seal is supposed to form. As a result, these impurities will cause scratches on the dynamic seal surface, which could, in turn, lead to premature pump failure. To remove all the debris from the cooling system, flushing is key. A hose and a standard cleansing agent might do, but using a flush tool like the Gates Power Clean Flush tool will help you to do the job properly. Tip: if you flush the cooling system with a water pump attached, use the old water pump and not the new one, to prevent impurities from contaminating the new pump.

3. Don’t Apply Sealant to an O-Ring or a Dry Seal

When changing a water pump, replace all old gaskets and seals with new ones. If your new  pump comes with a seal, make sure it’s in impeccable condition before installing it. (Some seals are so thin you could easily damage them when you rip off the packaging.) Perhaps you’re tempted to apply sealant to an O-ring or a dry seal, just to be ‘extra safe’, but these seals don’t need sealant! If your rubber ring won’t stay put, just use a drop of coolant or oil instead.

Only apply sealant if the vehicle manufacturer recommends it, and don’t use too much of it. Put a thin, even bead along the edge and wipe off the excess before mounting the water pump. If you do this after you’ve mounted the water pump, you won’t be able to see the excess sealant on the inside, where it will damage the cooling system. The sealant will clump together into chunks that contaminate the coolant and can cause leakage or do terrible damage to the thermostat.

Only apply sealant if the vehicle manufacturer recommends it, and when sealant is prescribed, be sure to use in the correct way.

4. Don’t Use Coolant That’s Old or Too Cold

Collecting the coolant from your old water pump and reusing it may seem like a sensible (and economical) thing to do, but we strongly advise against it. After all, coolant tends to deteriorate: it has an expiry date. Refill the cooling system with new coolant and make sure …

  • … to use the kind recommended by the vehicle manufacturer (don’t start mixing coolants either, because they might counteract each other).
  • … to get the proportions right. If you add too little antifreeze, your cooling system is more likely to freeze, but adding too much might also be harmful. We recommend a fifty-fifty mix of water and antifreeze (make that 65% antifreeze and 35% water for Alpine-cold or Siberian climates).
  • … to mix in warm water with your antifreeze – as odd as that may sound. Adding cold coolant to a heated engine can cause thermal shock and damage the seal, even in a new water pump.
  • … to use distilled, deionized or even bottled water, but never tap water. Regular tap water can be very hard, leaving mineral deposits inside the radiator, heater core and engine block. When these deposits break off, they can damage the water pump seal.

5. Do Rotate the Pump Manually

A lot of mechanics stick to the following procedure: replace the water pump, tighten the bolts, install the belt, tighten the tensioner, refill the cooling system … and start the engine (or just rev it up). But coolant takes a little time to get everywhere it’s supposed to be, so the water pump runs dry for a few seconds. This ruins the seal and heightens the risk of premature leaks or a noisy water pump. Instead we’d advise you to ease the car down after you’ve installed a new water pump, refill the cooling system, lift the car back up and manually rotate the pump about ten times, all the while making sure it rotates freely. Due to this rotating movement, coolant gets sucked into the mechanical seal component, effectively creating a film, which keeps coolant from spilling out.

6. Don’t Worry About Seepage from the Weep Hole

Every mechanically driven water pump has a weep hole that might leak a little in the beginning. Some seepage from the weep hole is completely normal with a new water pump: a mechanical seal has a break-in period of about ten minutes (meaning that it takes about ten minutes of operation for the seal to properly seal itself). However, if you still see seepage a few days after you’ve replaced the pump, or if you notice more pronounced seepage or even drips from the weep hole, you do have a problem: these symptoms point to a faulty installation.

7. Do Properly Vent the Cooling System

When you’re done replacing a water pump, it’s good practice to burp the cooling system to get rid of all the trapped air. Some thermostats have a small hole at 12 o’clock, and a jiggle pin which allows the air to escape (while preventing new air from getting in).

8. Do Change the Water Pump, Belt and Other Drive Components at the Same Time

It is crucial to inspect the belt drive system that is driving the water pump, while you’re at it. A bad belt and tensioner cause premature bearing and shaft failure and drastically reduce pump life. Conversely, a leaking water pump inevitably affects the belt and tensioner. That’s why we recommend changing the water pump, belt and other drive components all at the same time. Our timing belt kits and accessory belt kits include water pumps or even water pumps and thermostats.

9. Do Change the Coolant Every Five Years

Coolant contains anti-rust agents, corrosion inhibitors and lubricants for the water pump, yet these components deteriorate over time. Our rule of thumb: change the coolant every five years to preclude cavitation problems. After all, coolant tends to become more acidic over time, increasing the risk of cavitation – a bizarre phenomenon in which what seem like tiny ‘air bubbles’ pop and damage the paddle wheel and other components. (These ‘air bubbles’ actually contain super-hot vapour that can crack plastic and erode metal if it implodes). You cannot see the cavitation bubbles, but engine overheating and weep hole leaks are tell-tale signs.

TVD & Multi-Ribbed Belt Installation

Gates look at reducing the risk of premature drive system failure.


Torsional Vibration Dampers (TVDs) are crankshaft pulleys that protect components in accessory drive systems. They take out the NVH (noise vibration hardness) generated by the crankshaft. The pulleys achieve this thanks to rubber elements that connect the two main metal parts (Fig 1). The rubber is a damping agent, designed to absorb most of the vibrations. That’s why Gates encourages mechanics to install belt kits that include TVDs.

Consequential wear

Absorption of vibrations eventually causes TVD wear and sometimes misalignment. As well as providing less protection for other components, worn TVDs generate vibrations of their own. These excessive vibrations and noises are often misdiagnosed as problems caused by multi-ribbed belts.

Reasons for TVD replacement

TVDs begin to fail because:

  • Internal rubber elements degenerate through wear
  • Vibrations gradually increase
  • Worn ‘stretch’ bolts add vibrations

Top TVD tips

Drive system components that are installed together should be replaced at the same time.

  • Never replace TVDs with ordinary crankshaft pulleys
  • Cheap/fake TVDs that
    contain no damping elements could cause crankshafts to break
  • Always replace TVDs as part of belt kits

The best way to optimise performance and maximise protection for all drive system components is to install a TVD as part of a belt kit.

GATES TRAINING: Timing Belt Knowledge – Part 1

GATES TRAINING: Timing Belt Knowledge – Part 1

John demonstrates how to properly install and tension a timing belt.

GATES TRAINING: Timing Belt Knowledge – Part 2

GATES TRAINING: Timing Belt Knowledge – Part 2

John demonstrates the proper installation technique on a double overhead cam engine which includes a hyd tensioner. John finishes up with a discussion on timing belt failures.

GATES TRAINING: Accessory Belt Drive System (ABDS) – Avoid Customer Comebacks!

GATES TRAINING: Accessory Belt Drive System (ABDS) – Avoid Customer Comebacks!

Listen as John Gardner and Chase Vlieg provide solutions for solving specific problems under the hood of a Toyota along with an overview of the Accessory Belt Drive System (ABDS).

GATES TRAINING: Accessory Belt Drive System

GATES TRAINING: Accessory Belt Drive System

Check out this animated depiction of the Accessory Belt Drive System (ABDS) and its failure modes as well as the effects of these failure modes.