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CAMSHAFT

For an internal combustion engine to generate power, it needs three critical components – a set of pistons, a crankshaft and one or more camshafts.

INSTALL LEVEL OF DIFFICULTY

VERY DIFFICULT

What Is a Camshaft?

For an engine to operate, a mixture of air and fuel needs to be introduced to the combustion chamber which, when detonated by a spark, causes the pistons to move and turn a drive-producing crankshaft.

The fuel mixture needs to be introduced and the exhaust gases removed using valves, which are very precisely opened and closed by the engine’s camshaft. This shaft has several eccentric lobes attached to it that can effectively push against the valves to open them strategically, while valve springs allow them to return to their “shut” position to complete the process.

Some engines have one camshaft, while others may have two, but the job is the same – to operate the valves and control compression.

How Does a Camshaft Work?

While the shaft itself is designed to spin at very high speeds with consistency, the critical component here is the cam and more importantly its shape. The profile is fashioned so that the valves operate in anticipation of intake and extraction and to allow them to open wider at very high speeds.

The setup of the camshaft becomes even more important as the size of the engine and its intended performance increase and for example, with a double overhead cam engine there are a total of four camshafts.

For this system to operate correctly, the speed of rotation of the camshaft must be carefully controlled and it is linked to the crankshaft via a timing chain or gear mechanism in order to coordinate everything. However, the ultimate timing of the camshaft can be adjusted to provide power differentials.

How Is a Camshaft Made?

A typical camshaft is derived from billet or cast steel and machined to a very high accuracy. Engineers will typically use CNC machines or lathes to grind the proper profile into the various lobes.

How Does a Camshaft Fail?

  • Improperly lubricated
  • Excessive end play
  • Impact from other moving parts during operation

What Are the Symptoms of Failure?

  • Poor engine performance

What Are the Consequences of Failure?

  • Considerable damage to the internal components of the engine

A camshaft has been a part of the engine’s internal components since the invention of the automobile and as a component, they very rarely fail by themselves. Typically, failure is a result of incorrect installation or other component breakdown.

If you have questions or concerns about Camshafts or any of your vehicle’s components, come into your local Pep Boys where we can answer any question, help you find any part, or perform any vehicle service you might need.