A camshaft is a rotating object usually made of metal with sharp edges that convert rotational motion into reciprocal motion.
Camshafts have been used in electric motors‘ internal combustion engines (to drive the intake and exhaust valves), mechanically operated ignition systems, and early speed controllers.
Car camshafts are made of steel or cast iron and are critical factors in determining the engine’s speed range and power range.
The ridges are oval-shaped protrusions placed precisely along the axis. The length of the shaft and the number of blades or edges are directly related to the number of cylinders and valves in the engine. Camshafts are made of mild steel or cast alloys.
It’s pretty simple, but what does it do? The camshaft opens and closes the valves in the cylinder head. As the camshaft rotates, the upper points of the cams press the valve lifters.
This movement forces the valves to open, and the valve springs return the valve to a seated position as soon as the camshaft lobe rotates.
History
The Muslim engineer Al-Jazari described the camshaft in 1206. He used it as a court clock in vending machines, water lifting devices, and water clocks.
Among the first cars to use single camshaft engines was introduced in 1902, the Maudslay, designed by Alexander Craig, and the Marr Auto Car, designed by Walter Lorenzo Marr, born in Michigan in 1903.
Presentation Functions
Duration
The life of the camshaft determines how long the intake/exhaust valve is open, which is why it is a crucial factor in the amount of power produced by the engine.
Longer life can increase horsepower at high engine speeds (RPMs), but it can compensate for the reduction in torque at low RPM.
The measurement of camshaft life is affected by the amount of lift selected as the start and endpoint of the size.
A 0.050-inch lift value (1.3mm) is often used as a quality measurement procedure, as it is considered the most representative in the area of the elevator that defines the speed range in which the motor produces maximum power.
Different lift points determine camshaft power and idle power characteristics of the same duration (e.g., 0.006 or 0.002 inches), which can differ considerably from the rated camshaft at the 0 lift point. 05 inch.
Long-term side effects may increase, determining the duration of the suction openings and the exhaust valve.
The overlap has the most significant impact on idle quality, as the intake “leak” that immediately comes out of the exhaust valve that occurs during the overlap reduces engine efficiency and is more significant during low-speed operation.
In general, increasing the life of the camshaft will usually increase the overlap unless the rib clearance angle is increased to compensate.
Lift
The camshaft lift determines the distance between the valve and the valve seat (i.e., the degree to which the valve opens).
The higher the valve is lifted from the center, the more airflow can be ensured, thus increasing the power output.
More excellent valve lifts can have the same effect of increasing peak power as duration without the inconvenience of increased valve overlap.
Most top valve motors have a rocker arm ratio greater than one, so the valve opening distance (valve lift) is greater than the distance from the top of the shaft blade to the base circle (camshaft lift).
Several factors limit the maximum possible lift of a particular engine. First, as the lift increases, the valves approach the piston, so over-lifting can cause the collision to drop and damage the valve.
Second, greater lift means a more pronounced camshaft profile is needed, increasing the forces required to open the valve.
One problem with this is that the valve floats at high speeds, with the spring tension not providing enough strength for the valve to follow the tip-up or prevent the valve from rebounding as it returns to the valve seat.
This could result from a very steep blade rise, where the spacer ridge separates from the gear blade (due to the valve assembly’s inertia being greater than the spring’s closing force).
The valve float causes a loss of power at high speeds and, in extreme situations, can cause the valve to distort if the piston hits it.
Timing
The time interval between the camshaft (phase angle) and the crankshaft can be adjusted to shift the engine power range to another speed range.
Camshaft advance (crankshaft time advance) increases low torque, while camshaft deceleration (movement next to the crankshaft) increases output torque. The changes required are relatively small, often on the order of 5 degrees.
Modern variable valve timing engines can often adjust the camshaft timing according to the engine speed. This avoids the pre-compensation necessary when selecting a fixed tuning time for high and low-speed use.
Lobe Separation Angle
The lobe clearance angle (LSA, also called the center lobe angle) is the angle between the midline of the intake ribs and the midline of the exhaust vanes.
Higher LSA reduces overlap, improving idle quality and suction; however, using a higher LSA to compensate for the excessive duration can reduce horsepower and torque.
Generally, the optimum LSA for a given engine is related to the cylinder volume ratio to the intake valve area.
How Do I Know if There is a Problem With the Camshaft?
As with all moving parts of the engine, the camshaft can have problems. This isn’t a common concern with most new vehicles, but it does happen often.
What Does a Camshaft Failure Look Like?
In most cases, the camshaft Engine Light will come on.
Camshaft error codes include the ignition skip code for a specific cylinder and possible camshaft position sensor codes.
Other symptoms include:
- Return or burst exhaust or intake pipe
- Press the upper end of the motor
- Engine failure
- Engine power loss
- Since none of these symptoms are unique to camshaft problems, a qualified mechanic must diagnose and correct them accurately.
Can the Camshaft Be Repaired?
Due to the manufacturing processes, camshaft repair is often not recommended.
Although some high-performance engines use proper camshafts, this is not cost-practical or useful for the average car.
If your vehicle needs a new camshaft, the best option is to replace the camshaft with a new one.
How Much Does It Cost to Repair/replace a Camshaft?
Camshaft replacement parts for most models cost around $200 to $500, plus associated gaskets and seals.
Working on a camshaft replacement is the most expensive part of a repair budget.
Expect $1,000 or more in labor costs or $1,200 to $1,500 for repairs on most models.
