In nearly all engines manufactured prior to the last 20+ years, timing belts would uniformly be manufactured from thick straps of tough, resilient rubber. To this day, hardwearing rubber materials remain a functionally ideal solution for the purpose of maintaining tension between vital moving parts in the short-to-mid-term.
However, over longer periods, rubber compounds are prone to degrading through constant exposure to excessive heat from the engine and contact with aggressive substances like motor oil. The result of this prolonged exposure would typically be a loss of optimal tension, which in turn negatively impacts on the precise opening and closing times of engine valves. This dictates the need for eventual replacement of a cambelt in order to restore faltering engine performance back to its previous peak.
As we’ll see further on in this guide, some modern variants of timing belts can be constructed from a variety of more high-tech materials, each of which brings with it a range of slightly different properties and features for consideration when planning future replacements and upgrades.