This month PMM turns its attention to an older technology reappearing in workshops – the timing chain. FAI Auto goes through some best practice tips on a Vauxhall Corsa.
Vehicle: Vauxhall CORSA Mk III 1.0Ltr 2009
Issue: Excessive noise from engine
Diagnosis: Timing Chain Failure
Action: Flush engine, replace complete timing system
Findings: Cause of failure due to partial oil feed blockage to hydraulic tensioner and chain wear caused by oil contamination. Vehicle had a very poor service history.
1. Add engine flush to the oil and run the engine for 10 minutes. This will reduce any contaminants in the engine oil galleries and improve engine hygiene.
2. Use the correct engine locking tool as recommended by the vehicle manufacturer. Failure to do so will compromise the timing/synchronisation of the engine.
3. When removing the timing chain kit, ensure all oil feed holes are inspected and any blockages are removed. Failure to rectify any existing obstructions will compromise the function and reduce the service life of the new timing chain kit.
4. Remove old oil residue or carbon deposits before refitting any components. Do not release the tensioners until the complete timing chain kit has been installed.
5. Thoroughly clean all parts and mating surfaces ensuring there is no damage. All contaminants must be removed. Insufficient cleaning will jeopardise the integrity of the repair.
6. Take care when replacing rotary seals, ensuring the seal is fitted completely flush and there is no damage to the sealing surfaces of the seal or the shaft.
7. Tighten fixing bolts to manufacturer’s recommended torque values using calibrated tools. Carefully turn over the engine by hand for two revolutions, ensuring there is no piston-to-valve contact. If contact is made, do not proceed until timing error is rectified.
8. Always install a new oil filter.
9. Sump pan, oil pump and oil pick up pipes must be thoroughly cleaned and inspected for damage and any damaged parts must be renewed.
10. Refill engine with the correct amount and grade of oil as recommended by the vehicle manufacturer. Incorrect oil can result in catastrophic failure. Always inform your customer of the oil used, and advise that they must use the same oil for topping up if required.
11. For PTFE oil seals, do not use any oil to lubricate the seal and allow four hours before starting the engine. This will ensure the PTFE material has had the required time to form a fluid tight seal. When replacing gaskets, never use any additional sealants.
When fitting a replacement FAI timing chain kit, it is vital that the original cause of failure is identified and rectified. The installation must then be undertaken in clean conditions and any built-up contaminants completely removed. It is recommended that the oil sump is removed and the oil pick up pipe is flushed clean. Camshafts must be examined for damage prior to fitment and replaced if required. Always use the correct specification/grade/composition of oil and replace the oil filter. The oil lubrication system is thoroughly cleaned of contaminants/blockages.
