Engine Camshafts: Insider’s Guide

The engine camshaft is a crucial mechanical component that drives the engine’s valve operation and guarantees optimal engine performance. With this knowledge, you will be able to maintain and rebuild your camshaft and avoid costly repairs.

In this article, we will pay attention to the world of engine camshafts and explain what they are, and their significance in engine operations.

What is engine camshaft?

The engine camshaft is a vital component that oversees the opening and closing of the engine’s valves, ensuring that the intake of air and fuel and the expulsion of exhaust gases occur at the precise moments during the combustion cycle.

Essentially, it’s a rod-like structure with eccentric lobes that, when rotated, push against the valves to manage their movement, directly influencing the engine’s performance, power output, and efficiency.

The camshaft works in harmony with the crankshaft via a timing belt or chain, maintaining synchronized operations within the engine. Its design and operation are crucial for ensuring smooth, efficient, and powerful engine functionality.

Types of engine camshafts

Engine camshafts come in three main types.

• Single Overhead Camshaft (OHC): In the OHC design, there is one cam per head. The camshaft is located on top of the cylinder head. This design offers several advantages over pushrods such as higher valve lift, more precise control over timing events and generally superior performance because there is less friction between the components.

• Pushrod Camshaft Design: Pushrod camshaft design has the camshaft located in the engine block, and the camshaft actuates the valves through pushrods. Pushrod cams use a combination of rocker arms, lifters, springs and rods to transfer motion from the cam lobe to the valves below it.

• The Dual Overhead Camshaft (DOHC): The DOHC design features two camshafts, one for the intake valves and one for the exhaust valves, providing even greater control over valve timing and lift.

What engines have 4 camshafts?

Engines with 4 camshafts are typically found in performance-oriented or luxury vehicles and are commonly referred to as Quad-Cam engines. These engines usually have a Double Overhead Camshaft (DOHC) design in a V-shaped configuration, meaning there are two camshafts per bank of cylinders – one managing the intake valves and the other controlling the exhaust valves.

Examples include various engines from manufacturers like Porsche, Ferrari, and Lamborghini, where high-performance and optimal valve control are paramount.

The four-camshaft setup allows for enhanced control over valve timing and operation, contributing to improved power output, efficiency, and overall engine performance, especially in scenarios demanding high RPM and precision.

What are the parts of an engine camshaft?

An engine camshaft is made up of several key parts, including cam lobes, journals, and bearings.

• Cam Lobes: They are the raised sections of the camshaft that control the opening and closing of the engine’s valves. Accurate valve timing is essential here.

• Journals: Journals are the smooth sections of the camshaft that ride on the bearings, allowing for smooth rotational motion.

• The Bearings: The bearings support the camshaft, allowing it to rotate freely within the engine block.

These three parts work together to ensure the camshaft operates smoothly and efficiently, delivering precise and controlled valve timing.

What is the function of an engine camshaft?

There are three main functions of an engine camshaft.

• Valve Operation: The camshaft uses its lobes to push against the valves, controlling their opening and closing in sync with the engine’s cycles.
• Fuel and Air Management: By governing the valves, the camshaft regulates the intake of air and fuel and the expulsion of exhaust gases, directly impacting the combustion process.
• Timing Management: The camshaft, often connected to the crankshaft via a timing belt or chain, ensures that valve operation is perfectly timed with the piston movements.

Can an engine camshaft fail?

Common reasons for engine camshaft failure are;

• Wear and Tear: When the camshaft’s bearings and journals wear down over time it increases friction and engine noise. Also, it will reduce the performance of the engine.

• Overheating: Excessive heat can cause the camshaft to warp or crack, leading to failure. Overheating can be caused by a variety of factors, including insufficient lubrication, poor cooling, or high engine RPMs.

• Lack of Lubrication: The camshaft requires proper lubrication to prevent excessive wear and heat buildup. A lack of oil or poor oil pressure can lead to camshaft failure.

• Improper Installation: If the camshaft is not installed properly, it can cause premature failure. This can include incorrect positioning, incorrect torque values, or incorrect clearances.

• Engine Overload: The camshaft can bend or break if the engine is subjected to excessive loads. This can be caused by high engine RPMs, heavy loads, or improper tuning.

What are the signs that may indicate an engine camshaft failure?

• Engine Noise: If you notice increased knocking or ticking sounds, it may indicate a failing camshaft.

• Reduced Engine Performance: When the camshaft fails, it can result in reduced engine power, decreased fuel efficiency, and a decrease in engine RPMs.

• Engine Misfire: If one or more cylinders are not firing correctly, that will result in a misfiring engine. It can also be a sign of a failing camshaft.

• Engine Warning Light: If your vehicle’s check engine light comes on, that can be an indication of a failing camshaft.

• Engine Oil Leaks: A failing camshaft can cause oil leaks from the engine, which can lead to further engine damage.

• Excessive Engine Vibration: If the camshaft is not functioning properly, it can cause excessive engine vibration, which can be felt through the steering wheel or pedals.

The above can be signs of other issues in the engine. Therefore, it is advisable to check your car with an experienced mechanic.

Can I rebuild the camshaft?

A camshaft’s buildability must be assessed by a remanufacturer before rebuilding it. To do this, they must check for the following:

1. Straightness: The camshaft must be straight. This is not usually an issue with heavy-duty cams, as they are highly durable.
2. Lobe wear: Camshafts can be rebuilt if they have lobe wear, as long as it is not excessive. A rebuildable camshaft has slight wear while a non-rebuildable one has a chunk of metal missing, indicating extreme mechanical interference. The extent of acceptable wear varies depending on the camshaft and engine specifications.
3. Case hardening depth: The case hardening depth is the outer layer of hardened metal on the camshaft that endures friction on the lobes. The camshaft must have enough depth for the rebuilding process, which involves grinding the surface. Determining the case hardening depth requires special equipment in a machine shop.

Summary

This article offers a detailed overview of engine camshafts, highlighting their critical role in managing engine valve operations and ensuring optimal engine performance. It explores various camshaft types, such as Single Overhead Camshaft (OHC) and Dual Overhead Camshaft (DOHC), and discusses their unique designs and applications. Additionally, the piece outlines the different parts of camshafts and provides insights into potential causes and indicators of camshaft failure, making it a valuable resource for understanding the significance and functionality of engine camshafts.

For a deeper dive into maintaining various car parts and understanding automotive intricacies, explore more articles on the CarFinite Blog.