Overhead Valve vs Overhead Cam Engines: Understanding the Differences

overhead cam vs overhead valve

Automobile manufacturers design engines with different camshaft configurations, each with its own sets of advantages. In this regard, overhead cam vs overhead valve is among the most debated topics when considering car engines, performance, design and utility. Which one has a better or more compact design? Which provides more power?

Here’s a comprehensive comparison between the overhead cam vs overhead valve engines.

OHV vs OHC Engines: What Distinguishes Them?

Several factors distinguish the two engines. The design is the main difference between the overhead valve and overhead cam engines. While OHV engines are cost-effective, OHC engines offer better performance. 

Let’s explore more differences between the overhead valve vs overhead cam engines’ reliability, pros and cons and working.

Design and Configuration

OHV vs OHC working and design
OHC engines have two types, whereas OHV is a type of pushrod engine

An OHC engine has a camshaft on top of the valves, whereas OHV has a camshaft between the valves. That said, both configurations have distinguished functions and working. 

Overhead cam engines come in two configurations, i.e. inline or V-engines. Meanwhile, the OHV is a type of pushrod engine. Moreover, OHC has two types: dual overhead cam and single overhead cam engines. You can learn the differences between SOHC and DOHC engines to understand their design in detail.

After the design, another difference between the overhead valve and overhead cam engines is their working.

Working

The overhead cam engines have a camshaft located at the top actuating the valves. The crankshaft rotates the camshaft. After that, the lobes push the valve stems, causing them to open and close as the lobes rotate. The valve springs provide the return force, while the timing belt couples the overhead camshafts to the main shaft. 

On the other hand, overhead valve engines have only one cam placed between the V of the cylinder banks on the opposite. The single camshaft lobes actuate the pushrods. These pushrods transmit linear displacement to rockers. Then, the rockers redirect the motion down, pushing the valves downward. 

Overhead Valve vs Overhead Cam Engines: Pros and Cons

Both engines have their pros and cons. One must weigh these benefits and drawbacks when buying a car. 

Pros and Cons of OHC Engines

OHC pros and cons
OHC engines provide higher RPM than the OHVs

Learning the advantages and disadvantages of overhead cam engines is essential when buying a car with SOHC or DOHC engines.

Here are the benefits of OHC engines:

  • They provide improved performance compared to other engine designs. The direct actuation of the valves allows precise valve timing and greater control over the intake and exhaust cycles, which can result in better overall engine performance.
  • OHC engines have higher RPM compared to the OHV engine. The lighter valve train and reduced reciprocating mass allow the engine to rev higher, potentially leading to increased power output.
  • Better fuel efficiency is another advantage of an overhead cam engine compared to the overhead valve. Efficient valve control and reduced internal friction contribute to improved combustion efficiency and reduced fuel consumption.
  • Variable valve timing (VVT) technology is also found in overhead cam engines. 

Here are the cons of OHC engines:

  • OHC engines have a complex design with more components compared to the pushrod engines. This complexity increases its weight. Moreover, the manufacturing, maintenance and repair costs are higher.
  • These OHC engines have a narrow torque band that produces less low-end torque, requiring higher RPMs to achieve maximum power. It can result in a less responsive engine at lower speeds.

Pros and Cons of OHV Engines

OHV engines reliability
Overhead valve engines have better durability and reliability

The following are the advantages of the overhead valve engines:

  • It was part of the classic muscle cars by American auto manufacturers that produced high power and performance.
  • The OHV engines have a compact size and less weight than the OHC engines due to the less number of camshafts.
  • Its compact size and design lower manufacturing and maintenance costs.
  • OHV engines are known for their durability and robustness. Its components reduce the vulnerability to extreme temperatures and potential damage. 
  • OHV engines often exhibit strong low-end torque. It is one of the main differences between the overhead valve and overhead cam engines that require ample pulling power or towing capabilities.

Alongside its advantages, here are the disadvantages of OHV:

  • The OHV design may not provide optimal combustion efficiency compared to other engine configurations. The placement of the valves in the engine block can result in less efficient airflow and fuel mixture compared to engines with overhead cams. 
  • The pushrod design limits the speed at which the engine valves function, which can impact the engine’s ability to achieve high RPMs. 

Overhead Valve vs Overhead Cam Engines: Which Is Better?

what to choose from overhead valve or overhead cam engines
When choosing between the OHV vs OHC engines, consider their design, power and performance differences

Both engines have their benefits and drawbacks. It’s important to figure out the power and performance you need while driving a car. 

Overhead valve engines have produced better results in high-performance cars, such as Dodge Challenger and Chevrolet Corvette. However, OHC engines can be found in fuel-efficient vehicles, such as the Mercedes C300 and BMW X5.

This was a detailed comparison between the overhead valve vs overhead cam engines. When browsing through the used cars for sale in the UAE, decide the performance factors you need and the type of engine that will deliver the best before buying the vehicle.

Stay tuned to the dubizzle cars blog and learn more about different types of engines and their designs.

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