The camshaft is the "heartbeat" of the engine. It controls the valve opening and all engine parts ideally should match it to maximize engine performance. There are many options available when selecting a camshaft. Below are the answers to the most common questions about camshafts:
What Do Camshafts Do?
An engine camshaft controls the opening and closing of the intake and exhaust valves. It is driven by the crankshaft through a timing set. It controls the valves by moving the lifters and push rods vertically into the underside of the rocker arms, which pivot and then push down on the valves. The lobes on the camshaft are ramped to allow smooth transition of vertical up and down movement as the camshaft rotates. The height of the lobes produces the "lift", which is how far the valves open.
The amount of time the camshaft holds the valve open is the "duration". The longer the valves are open, the more air and fuel that can enter and exit the engine. Longer duration improves top end power at the cost of low-end torque and vice versa. Lobe separation angle is the amount of time that both the intake and exhaust valve are open at the same time in a cylinder. The lower the lobe separation angle, the rougher the idle and the more midrange power it will have. There are different types of camshafts to choose from when choosing the correct camshaft. The first choice is the lifter type: hydraulic or a mechanical lifter version.
They hydraulic is best for daily drivers and vehicles putting a lot of time and miles on the engine as lash adjustment is not needed periodically. A solid (or mechanical) lifter is best for applications over 6500 rpms and produces more horsepower than a hydraulic lifter, but requires frequent valve lash adjustments.
The choice for camshafts also involves the lifters: flat-tappet and roller. Flat tappets have a flat bottom on the lifter that contacts the camshaft lobe as the cam rotates. Roller lifters have a roller wheel that contacts the camshaft lobe, providing more power than flat tappet lifters due to the large decrease in friction.
However, the cost is a lot more due to the bearings and rollers required for assembly of the lifter. An important rule to follow is that lifters have to match the types of camshafts they are designed for. A solid flat tappet cam is only compatible with solid flat tappet lifters; a hydraulic roller camshaft only works with hydraulic roller lifters. If you need help picking the right camshaft, a JEGS expert is ready to answer your questions and help you with how to choose a camshaft that you require for your specific application.
What Are Camshafts Made Of?
Most camshafts are made from either cast iron or billet steel. Billet steel is stronger than cast iron and is ideal when using stiffer valve springs and with high horsepower engines due to the increased strength and wear resistance. However, they are more expensive than their cast iron counter parts. JEGS offers a large selection of camshafts to choose from that will meet your needs.
How to Install Camshafts
Installation of a camshaft can be an easy process with the proper planning and tools. To install the cam, the engine short block needs to be complete with the crankshaft installed so that the timing set can be added. If you are replacing a camshaft, the old camshaft, lifters, and pushrods need to be removed. The camshaft bearings need to then be inspected for wear or damage and replaced if necessary (or added if using a new block).
The new camshaft needs lubricated with camshaft assembly lube. Installation of a cam can be helped with a camshaft installation tool, which aids in holding it straight as it is carefully installed into the block. Care must be taken to ensure the cam does not damage the bearings as it passes through the block during installation. Once installed, the timing set needs to be added, making sure that the camshaft and crankshaft are properly clocked.
Once the timing set is installed, the lifters and pushrods can be added. Next, adjust the rocker arms to the proper valve lash, depending on the type of camshaft and according to the proper order and procedure. Finally, degree the cam. This is important to prevent piston to valve contact, confirm correct assembly, and to provide maximum performance.
