Meaning | Concept | Definition:
A timing cover is a component typically found on internal combustion engines and is designed to protect components such as timing gears and the chain or belt.
On applications using a timing chain, the timing cover typically seals the front end of the block, while engines with timing belts often have timing covers that are less integral. Timing covers can be made of metal or plastic
. Engines with timing chains generally have a metal cover, while those with a timing belt can use covers made from a variety of different materials.
A car’s timing gear and belt or chain are protected by a timing cover.
Timing chain covers are typically designed to seal off the front end of the engine block. This is usually so the timing gears and chain can be lubricated with engine oil.
These covers will usually seal to the block with a timing cover gasket, which can be responsible for leaking engine oil if it fails. Also, the crankshaft will normally go through a set of seals into the timing cover which may be leaking. Replacing a timing cover gasket is often a time-consuming job, while replacing a crankshaft oil seal is sometimes possible without removing the cover.
Engines that use a timing saddle, rather than a timing belt, typically have metal covers.
Timing covers are also used in conjunction with timing belts. In these applications, the front of the engine will normally be sealed with oil seals that are placed in the block or head where the crankshaft and camshafts extend.
With the engine otherwise sealed, the function of the timing belt cover is simply to protect the belt from damage. These covers can be made of metal or plastic and can be made up of several different pieces. Multi-piece timing belt covers can even contain metal and plastic parts.
Timing cover gaskets are also often used with timing belt covers, although they are designed to keep contaminants away from the belt.
If an oil leak develops at a crank or camshaft seal, the oil can contaminate the timing belt and require replacement. Oil can also contaminate the lid gasket, causing it to swell and become unusable. In these cases, the seal, belt, and gasket are often replaced at the same time.
In some cases, timing belt covers will use special timing cover bolts.
These bolts typically have a thick shoulder that allows them to tighten without breaking the plastic cover. In other cases, the cover may have metal bezels on the bolt holes that are designed to perform the same function.
Car and truck engines use many types of gaskets, including to seal the timing cover.