DOHC Vs. SOHC – 12 Major Differences Everyone Should Know!

Written By: Terrence Hines
Category: Uncategorized, Engine

Regarding vehicular performance, the debate often concerns DOHC vs. SOHC engine designs. Both have unique features, each with pros and cons.

While DOHC offers greater power and efficiency, SOHC is known for its simplicity and cost-effectiveness. Let’s delve deeper to understand which stands superior.

DOHC Vs. SOHC – 12 Major Differences!

DOHC, Double Overhead Camshaft, and SOHC, or Single Overhead Camshaft, are prominent engine designs in modern vehicles.

The DOHC design features two camshafts, one for intake valves and the other for exhaust valves, allowing for more efficient fuel combustion and greater power output.

On the other hand, the SOHC design employs just one camshaft to control both the intake and exhaust valves.

This simplicity makes SOHC engines less complex, easier to maintain, and more cost-effective.

The choice between DOHC and SOHC largely depends on one’s specific needs and preferences in vehicle performance.

Here are some major differences to consider when making the decision.

1. Number Of Camshafts:

DOHC (Dual Overhead Cam) engines, renowned for their performance, are equipped with two camshafts, one for the intake valves and one for the exhaust valves.

DOHC Vs. SOHC - 12 Major Differences!

This dual configuration allows precise control over the valve timing, improving efficiency and power delivery.

On the other hand, SOHC (Single Overhead Cam) engines utilize a single camshaft to perform both functions, which can limit the level of control over the valve timing.

The difference in camshaft configuration contrasts these engine types, including variations in valve lift, duration, and overall performance.

2. Valve Control:

DOHC (Dual Overhead Cam) engines have an extra camshaft that allows independent control of intake and exhaust valves, resulting in precise valve timing.

This enhanced control over valve timing results in improved engine performance and efficiency.

On the other hand, SOHC (Single Overhead Cam) engines feature a single camshaft that governs both the intake and exhaust valves.

While this design simplifies engine construction and reduces manufacturing costs, it may affect valve timing and slightly impact overall engine performance.

3. Engine Speed:

Due to their advanced design, DOHC (Dual Overhead Cam) engines deliver higher speeds, allowing independent control of intake and exhaust valves.

This enables precise timing, optimal performance, and efficient combustion. DOHC engines enhance power output and responsiveness by maximizing airflow and fuel mixture.

On the other hand, SOHC (Single Overhead Cam) engines strike a balance between efficiency and reliability, operating at lower speeds.

While SOHC engines lack the high RPM levels of DOHC engines, their simpler design reduces complexity and cost.

Engine Speed

Different control mechanisms contribute to distinct engine performance and power delivery characteristics, suiting various applications and preferences.

4. Power Output:

DO (Dual Overhead Cam) engines, known for their enhanced valve control and precise timing, typically offer a higher power output due to their ability to intake and exhaust air efficiently.

This increased power makes them popular among performance enthusiasts who crave that extra boost on the road.

On the other hand, SOHC (Single Overhead Cam) engines, while not as power-packed as DOHC engines, still deliver sufficient power for most everyday driving situations.

Their design focuses on simplicity and reliability, making them a reliable and practical option for most drivers seeking a balance between performance and practicality.

Whether you prioritize raw power or a reliable everyday driving experience, both DOHC and SOHC engines have their merits and cater to different driving preferences.

5. Fuel Efficiency:

DOHC (Dual Overhead Cam) engines are fuel-efficient due to advanced valve timing optimization, adapting seamlessly to various driving conditions.

This intricate system meticulously controls the opening and closing of the valves, ensuring optimal combustion and power delivery.

On the other hand, while still efficient, SOHC (Single Overhead Cam) engines may consume slightly more fuel due to their less sophisticated valve timing mechanisms.

With a single camshaft responsible for both intake and exhaust valves, the timing precision may be compromised, resulting in a minor reduction in fuel efficiency.

6. Size And Weight:

Dual Overhead Cam (DOHC) engines, known for their superior performance, are typically larger and heavier than Single Overhead Cam (SOHC) engines.

This is mainly because the DOHC configuration uses separate camshafts for intake and exhaust valves, leading to better engine efficiency and power delivery.

Additional components in DOHC engines allow for precise valve control and higher RPM capabilities, thereby maximizing performance potential.

These factors contribute to the engine’s size and weight, resulting in a remarkable driving experience.

This is why DOHC engines are popular among automotive enthusiasts seeking unparalleled performance and power.

7. Noise And Vibration:

DOHC (Dual Overhead Cam) engines are known for generating low noise and vibration levels, setting them apart from SOHC (Single Overhead Cam) engines.

DOHC Vs. SOHC - Differences!

This is due to their superior valve control mechanism, which ensures precise and efficient operation.

With two camshafts per cylinder bank, DOHC engines offer optimal performance, reduced mechanical disturbances, and a smoother driving experience.

This design provides a quieter, more comfortable ride and improves fuel efficiency and engine longevity.

Whether cruising on the highway or tackling tough terrains, the advanced technology of DOHC engines delivers an outstanding driving experience that impresses and satisfies you.

8. Maintenance:

SOHC (Single Overhead Cam) engines are known for their simplicity and affordable maintenance.

With fewer components than DOHC (Dual Overhead Cam) engines, they offer a streamlined design that minimizes potential issues.

The single camshaft in SOHC engines operates both intake and exhaust valves, making it easier to adjust and maintain.

On the other hand, DOHC engines, with their additional camshaft and valves, require more intricate and costly maintenance due to their increased complexity.

The separate camshafts in DOHC engines allow precise control over valve timing, enhancing performance but requiring meticulous maintenance.

Understanding these differences helps make informed decisions on engine selection and maintenance for optimal performance and longevity.

9. Price:

Due to added complexity and performance advantages, DOHC (Dual Overhead Cam) engines are generally pricier than SOHC (Single Overhead Cam) engines.

With separate camshafts controlling intake and exhaust valves, DOHC engines achieve higher RPMs and better airflow, improving power and efficiency.

Precise valve control enhances combustion and fuel efficiency. More camshafts provide better control over valve timing, improving engine response and operation.

While cost is a factor, many automotive enthusiasts prefer the enhanced performance and refined operation of DOHC engines.

Looking for a power-packed engine with advanced features? Consider a DOHC engine.

10. Reliability:

DOHC (Dual Overhead Camshaft) and SOHC (Single Overhead Camshaft) engines are highly reliable.

The simplicity of SOHC engines gives them a slight edge in long-term dependability.

With fewer moving parts and a streamlined design, SOHC engines exhibit reduced wear and tear and contribute to better overall longevity.

This enhanced durability can translate into lower maintenance costs and a more cost-effective ownership experience.

Therefore, if you’re seeking an engine that offers a winning combination of reliability and simplicity, the SOHC option might be your ideal choice.

11. Emissions:

DO (Dual Overhead Camshaft) engines are renowned for maintaining lower emissions than other engine designs.

This is primarily due to their superior control over the timing and duration of valve openings, enabling more precise fuel combustion.

By optimizing the combustion process, DOHC engines effectively minimize the release of unburnt fuel, leading to reduced emissions and a cleaner environment.

Enhanced control and precision lead to a greener future and smoother engine operation, improving performance and fuel efficiency.


Thus, choosing a DOHC engine offers environmental benefits and a more sustainable and reliable driving experience.

12. Application:

DOHC (Dual Overhead CAM) engines are usually found in high-performance or luxury vehicles, renowned for their exceptional power and smooth operation.

On the other hand, SOHC (Single Overhead Cam) engines are more commonly seen in budget-friendly and everyday vehicles, offering reliable performance and fuel efficiency.

The choice between these engine types depends on the driver’s needs and preferences.

DOHC engines offer precise control over valve timing, while SOHC engines are more cost-effective to manufacture and maintain.

DOHC Vs. SOHC – Which Is Better?

When choosing between DOHC and SOHC engines, the decision depends largely on your needs and priorities.

If power output, superior fuel efficiency, and lower emissions are your priorities, then a DOHC engine would be a better match.

It’s a common choice for high-performance and luxury vehicles thanks to its enhanced valve control.

However, the added complexity of DOHC engines often results in higher costs and more elaborate maintenance requirements.

On the other hand, the simplicity of SOHC engines makes them more accessible, easier to maintain, and generally more reliable over the long term.

They deliver ample power for everyday driving and are commonly found in more budget-friendly vehicles.

CriteriaDOHC (Dual Overhead Cam)SOHC (Single Overhead Cam)
Power OutputHigher power output, especially at high RPMsSufficient power for everyday driving
Fuel EfficiencyGenerally superior fuel efficiencyGood fuel efficiency
EmissionsLower emissionsGood emissions performance
ComplexityMore complex design with separate camshaftsSimpler design with a single camshaft
MaintenanceHigher maintenance costs and more elaborate maintenance requirementsEasier maintenance and generally more reliable
CostGenerally higher costsLower manufacturing and maintenance costsover the long term
ApplicationCommon choice for high-performance and luxuryCommonly found in more budget-friendly vehicles

Ultimately, when examining DOHC vs. SOHC, the choice is balancing performance, maintenance ease, and cost.


The choice between DOHC and SOHC often concerns your specific needs and circumstances.

While DOHC engines offer greater power output, fuel efficiency, and lower emissions, they come with a higher price tag and maintenance cost due to their added complexity.

On the other hand, SOHC engines, with their simpler design, provide sufficient power for everyday driving, are easier to maintain, and are usually more affordable.

Whether you value high performance and efficiency with DOHC or prefer simplicity and cost-effectiveness with SOHC, it’s essential to know DOHC vs. SOHC.

By understanding the intricacies and nuances, you can make a well-informed decision that aligns perfectly with your needs and requirements.

Terrence Hines

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