Timing belt verses timing chain

[thexav]

Which is better to have, a timing chain or a belt?

Can you convert a timing chain into a belt or vice versa?

What is the job of the chain or belt, does it literally just rotate the cams with the engine? Why don't they use a motor or cogs to do this?

How often do you need to change a timing chain or a timing belt?

 

[wizzer]

Which is better to have, a timing chain or a belt?

Can you convert a timing chain into a belt or vice versa?

What is the job of the chain or belt, does it literally just rotate the cams with the engine? Why don't they use a motor or cogs to do this?

How often do you need to change a timing chain or a timing belt?

Both chains and belts can stretch but belts do this more. The chains tend to last longer and are more reliable but they cost more to buy and fit and are a bit of pig to get the tension right.

The rotation comes from the crank at the bottom of the engine so it's not practical to use cogs, and whilst some cars come with a motor activated camshaft lift you can't beat the simlicity of a driven camshaft that uses the crank.

To convert you'd need to swap out pulleys for cogs with teeth and replace the tensioner so it's not an easy swap to do and you have very little to gain by doing this.