Camshaft replacement in Kansas City, Kansas, done at your house

A camshaft is a long metal shaft with egg-shaped bumps along it, called lobes. As it turns, each lobe pushes a valve open and then lets it close. That is how air and fuel get into each cylinder and how the exhaust gets out. Every time the engine runs, the camshaft is turning right along with it.

On most newer engines the camshaft sits up top in the cylinder head, and many engines have two or more. On a lot of older V8s and some trucks it sits down in the middle of the block and works the valves through pushrods. Where yours sits makes a big difference in how much of the engine has to come apart.

The camshaft lives on a thin film of oil. When that film goes away, metal rubs on metal and the lobes start to wear flat. Low oil, oil that went too long between changes, or the wrong oil for the engine are the usual starting points. Once a lobe wears down, that valve doesn't open as far as it should, and the cylinder it feeds stops making its share of power.

The small bits of metal that come off don't go away on their own. They ride around in the oil, which is why metal in the oil is one of the signs.

None of these alone proves it. A ticking noise has plenty of possible causes, and so does a misfire. Josh puts the signs together and checks before he calls it a camshaft.

• A ticking or tapping from the top of the engine that speeds up as the engine revs
• Rough running, especially at idle
• A misfire you can feel as a stumble
• A check engine light that comes on and stays on
• Less power than the car used to have
• Shiny metal flakes in the oil or on the drain plug

The camshaft is turned by the timing belt or timing chain, which keeps it in step with the crankshaft. That means camshaft work almost always involves the timing parts too. To get the cam out, the timing has to come apart, and when it goes back together it has to be set exactly right or the engine runs poorly or not at all.

If your timing belt is close to due, or your chain has started to rattle, it often makes sense to handle both while the engine is open. Josh will tell you what he sees and quote it so you can decide. The timing belt and chain page has more on that side of it.

Camshaft work can be a moderate job on one engine and a very big one on another. An overhead cam on a roomy four-cylinder is one thing. A cam buried in the block of a V8 is another. Josh looks at your engine, tells you what it takes and gives you a clear quote before any work starts.

If the wear has gone far enough that metal has been through the whole engine, he will tell you that too. Sometimes the honest answer is a bigger repair, and you should hear that before you spend money on a part. Text Josh the year, make, model and engine and what you are hearing, and he can tell you where he would start.