Timing Chains

What is a timing chain?

A timing chain looks very similar to a bicycle chain and is responsible the maintaining the synchronisation of the crankshaft, camshaft, inlet and outlet valves. The inlet and outlet valves need to open and close at the proper time to be able to assist in the internal combustion process. Any chain in the engine is called a timing chain even though it may not directly be involved in valve timing. Chains for oil pumps and injection pumps can also be referred to as timing chains.

There are different types of timing chain as follows:

• Single row timing chain

• Duplex timing chain (double row chain)

• Open or closed timing chain

How do I choose the correct timing chain?

As the term ‘timing chain’ can be used to describe any chain in your engine not just the chain for the camshaft it is important to check what devices the chain is listed for. This information will be listed in the compatibility notes. You can also check these factors:

• Number of chain links

• Vehicle manufacture date (this is not the date the vehicle was registered but the date it was made

• Engine number sequence (up to or after as specific number/letter

• VIN (chassis number) sequence (up to or after as specific number/letter

What brand of timing chian should I choose?

Brands such as BGA and INA (Schaeffler) manufacture parts for the original car brands so they would be considered premium makers. Aftermarket brands such as Blue Print, Febi and Quinton Hazell offer long warranties which show they have confidence in their products. The choice of brand would be down to your budget and part availability.

How can I tell my timing chain needs replacing?

Timing chain failure can cause catastrophic damage to the engine. If a chain fails the engine will not function. If the chain has broken do not try to start the engine. We would always recommend that you have your vehicle inspected by a qualified mechanic to receive an accurate diagnosis that your chain has failed or needs replacement. Some of the symptoms of a failing or broken timing chain are:

• Rattling sound when the engine starts or is idling

• Engine will not start

• Check engine light

• Engine misfires

• Rough engine idling