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What is a camshaft and what does it do?

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Updated 10 Oct 2019

Jason Unrau

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An average internal combustion engine has thousands of pieces, and more than 200 are moving parts.

Of those components, the camshaft is one of the most important.

A car engine simply doesn’t run without one and doesn’t run well if the camshaft is damaged.

Since most people never disassemble a car engine, it’s hard to understand what it is and what it does.

Let’s look at what a camshaft is, what it does, and what happens if something is wrong.

What is a Camshaft?

Quite literally, the camshaft is a shaft with cams attached to it.

The cams are oval-shaped bulges placed precisely along the shaft.

The shaft length and the number of lobes or cams is directly related to the number of valves and cylinders that make up the engine.

Camshafts are manufactured of hardened steel or cast iron alloy.

That’s straightforward enough, but what does it do?

The camshaft opens and closes valves in the cylinder head.

As the camshaft rotates, high spots on the cams press on valve lifters.

That motion forces valves to open, and valve springs return the valve to the seated position as soon as the cam lobe rotates past.

But what makes the camshaft rotate, you might ask?

You’ve undoubtedly heard about a timing belt (or chain).

The timing belt connects sprockets on the front of the crankshaft and the camshaft so they operate in sync.

The crankshaft transmits energy to the camshaft for it to rotate, causing intake and exhaust valves to open and close.

How Do I Know if There’s a Problem with the Camshaft?

As with all moving engine parts, there’s potential for the camshaft to have issues.

It’s not a frequent concern on most newer vehicles, but it still happens from time to time.

What does a camshaft failure look like?

In most cases, the Check Engine light will illuminate.

Trouble codes related to camshaft issues include a misfire code for a specific cylinder and possible camshaft position sensor codes. Other symptoms include:

  • Backfiring or popping from the tailpipe or intake
  • Tapping noise from the top end of the engine
  • A dead miss in the engine
  • Loss of engine power

Because none of these symptoms are unique only to camshaft issues, it takes a knowledgeable mechanic to accurately diagnose and fix it.

Can the Camshaft be Repaired?

Due to the manufacturing processes, repairing a camshaft is not often advisable.

While some high-performance engines use camshafts that are repairable, it’s not really cost effective or practical for the average car on the road.

Instead, if your car needs a new camshaft, replacing it with a new one is the best choice.

What Does Camshaft Replacement Cost?

Parts to replace the camshaft for most models will be around $200 to $500 for the camshaft, plus related seals and gaskets.

The labour for camshaft replacement is certainly the most expensive part of the repair estimate.

Expect $1,000 or more for labour costs, tallying up to $1,200 to 1,500 for the repair on most models.

If you’re in need of a camshaft replacement, grab a quote off an expert mechanic through AutoGuru.

You’ll enjoy quick quote, transparent prices and the convenience of online booking!

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Written By

Jason Unrau


