On MGF and TFs a cambelt change on the K Series engine is recommended every 60,000 miles or four years, whichever comes first. Although the belt may look perfectly fine on a visual inspection, manufacturers don’t guarantee them any longer and a failure can happen without warning which could destroy an engine.
Although a simple sounding procedure, changing a cambelt is quite a complex operation due to accessing the belt, the requirement to do the work in a raised position, the need for accurate positioning of the timing mechanism and belt tensioning and, at the same time, the recommendation to replace the water pump. All in all it is a job best left to the experts who have both the knowledge and the equipment to undertake this process.
The cambelt cover, which is located on the end of the transverse mounted engine on the offside comes in two pieces, top and bottom, and these are held in place by a total of nine bolts.
To access the covers you first need to detach the hood from its rear securing points and tilt it forward to reach the engine bay cover that has to be removed to give access to the top and side of the engine. You will also need to remove the rear offside wheel and the inner wheel arch cover.
You may also need to remove the coolant bottle to get better access to the cambelt – this is held in place by two bolts and two clips. This will allow you to reach the five bolts which hold the top part of the cambelt cover in place – including a long one at the back.
Next operation is to remove the crank pulley to expose the bottom of the cambelt and access the bolts holding the bottom part of the protective cover.
Having now exposed the cambelt, before removing, set the timing position by locating the timing dots as well as the position marks on the exhaust and inlet crank gearing (see above) to ensure it is aligned correctly and use a locking tool for the cam pulleys.
As well as the cambelt itself, you can now see the water pump and the cambelt tensioner – it is recommended to replace both these at the same time even if they look in good condition. The water pump is vulnerable to corrosion and if is seizes it can strip the teeth off the cambelt.Undo the timing belt and tensioner and remove the 8mm bolts and 13mm treaded bolt on the water pump remembering to collect any water that will flow out.
Once off you can clean the pump locating point on the engine removing the old jointing compound to allow a flush fit – install a new pump (below left) using a new ‘O’ ring and gasket sealant – blue hylomar is recommended.
The camblet tensioner should always be replaced at the same time as the belt as it can wear and lose tension over time. On the MGF and VVC models this is an all metal unit, on the later models they changed to plastic units. Before you can remove the belt you will need to place a long jack under the car to hold the engine in place while you remove the off-side engine mounting bolt, then lower the engine by a fraction which allows you to remove the cambelt from its position.
Fit the new cambelt (below) and make sure that it is inserted so that it is running in the correct direction – the writing should be facing you. Reposition the engine and re-attach the securing bolts.
Finally, fit the new tensioner and check that the tension is correct on the belt – torque up the tensioner to the correct setting and use lock tight solution as an added precaution.
With everything back in place and the timing dots aligned you can reverse the process to fit the cambelt covers.
A normal cambelt change takes around an hour-and-three-quarters and two-and-a-quarter for a VVC. If this is incorporated into a routine service the whole operation can take two-and-a-half hours.
The cost of replacing a ‘K’ series cambelt and tensioner on its own is £179 inc VAT (remember HAS offer club members a 10 per cent discount). Replacing a cambelt, tensioner and water pump plus fresh antifreeze and the labour to bleed out the coolant system costs £325 inc VAT. For VVC engines, replacing both cambelts and tensioners costs £235 inc VAT with a water pump change that brings it up to £379 inc VAT.