Your camshaft, sometimes called the "brains" of your engine, manipulates the valves that allow fuel and air into your engine. Your vehicle simply won't function without it, and the kind of camshaft you get determines engine qualities ranging from how much power and performance you can get to how well your engine idles. Picking out the right camshaft can be quite complicated. If you're looking to replace your camshaft with something other than the exactly the same type you started out with, here are some things you need to know:
Camshafts are usually made out of either of two types of material: chilled iron castings or billet steel.
- Chilled iron castings - This is the most common type. The chilling process makes the material harder. That, and elements added to the iron used, make for very durable camshafts for most driving applications.
- Billet steel - This is used only for very high-quality camshafts. A special heat-treating process called gas nitriding is used to make the steel extremely hard. This type of camshaft is much more expensive and is used for high-performance engines.
There are four basic types of camshafts. The type is determined by whether it's a roller camshaft or a flat tappet camshaft, and whether each type uses a hydraulic or a solid lifter.
- Flat tappet camshafts - These use a lifter with a slightly curved bottom sliding against the cam lobes. The curved bottom helps reduce friction. Flat tappet camshafts were in almost every V8 engine produced the late 1980s. They are still quite common and are relatively much cheaper.
- Roller camshafts - With a roller or wheel rolling over the cam lobes, the amount of friction and wear is greatly reduced in these camshafts. Roller camshafts provide better performance by allowing for more mid- to top-end power without compromising bottom-end power. These are much more expensive than flat tappet camshafts.
- Hydraulic lifters - These automatically adjust the valve lash (the distance between the valve stem and rocker arm tip) as needed. They are quieter, require almost no maintenance, and cause much less wear on the valvetrain. The only problem is how they may overfill with oil, causing the valves to stay open too long at high rpm. This can lean to engine damage at high speeds.
- Solid lifters - These are more ideal for racing since they don't have the oil-overfill problem of hydraulic lifters. However, they are also noisier and require periodic adjustment of the valve lash.
Other things to consider:
- As always, your vehicle's owner manual is a good place to start looking for information regarding any parts you plan to get for your vehicle.
- Your replacement camshaft must be compatible with your engine's cylinder head. Know the exact specifications of your cylinder head (make, model, size of intake/exhaust valves, etc.) and see if the camshaft you're getting can work with them.