Some PSA Group vehicles (Peugeot, Citroën etc.) built between 2018 and 2022 and equipped with the DV5 engines experienced premature wear of pivotal engine components, with these issues primarily occurring in vehicles equipped with 7mm timing chain units. 

• Why premature wear occurs in DV5 engines?  
• How does this issue affect key engine components?  
• What measures can we take to mitigate this problem? 

In this article, we will look at the limitations of DV5 engine and explore solutions to maximize engine life and improve its performance by upgrading to an 8mm camshaft kit from the REVVSUN.

The Problem: 

The inherent conflict between diesel combustion characteristics and emission control systems remains a persistent challenge for engine technicians.

The DV5 1.5L BlueHDi diesel engine employs EGR (Exhaust Gas Recirculation) and DPF (Diesel Particulate Filter) systems as compromise solutions to meet the stringent Euro 6 emission control standards. While effective at reducing emissions, these systems promote soot accumulation, accelerating engine wear—especially during low-speed, short-distance driving or in urban environments with poor air quality.  

The generation of NOx highly relies on combustion temperature. EGR recirculates exhaust gas and inhibits the activation reaction of nitrogen and oxygen by lowering the combustion temperature, promoting emission reduction. However, the smoke and acidic substances contained in the exhaust gas will greatly dilute the fresh air, resulting in incomplete combustion. The residual waste not only wears out engine parts but also accelerates the acidification of the oil and corrodes engine parts.

The DPF captures soot particles (PM) in the exhaust gas and removes them through periodic regeneration and high-temperature combustion. DPF exhaust temperature is often insufficient during low-speed driving in the city. The increase in regeneration frequency often leads to incomplete regeneration, continuous accumulation of smoke, and increased oil pollution. These issues collectively cause permanent wear of the 7mm timing chain and camshaft sprocket.

The original 7mm chain may have the following problems under long-term high load:

• Chain wear causes timing delay, reducing power output and  increasing emissions.
• Risk of chain skipping after stretching, which may cause engine damage in severe cases.

The Solution:

To solve the premature wear of the timing chain and camshaft sprocket, the original factory changed the camshaft timing chain pitch from 7mm to 8mm. Increasing the chain pitch has two direct effects:

• Increase the chain stress area:

    When the pitch increases, the roller diameter and chain plate thickness of the chain typically increase proportionally by 16%, so that the contact area of each link becomes larger, thereby dispersing the load and reducing the stress per unit area. Reduce the contact pressure between the chain and the gear and reduce wear.

• Enhance the tensile strength:

A larger pitch usually means greater tensile strength, which can better cope with the high torque conditions of diesel engines and reduce the plastic deformation of the chain caused by long-term stress.

To accommodate the increase in chain size, the camshaft and cylinder head cover are modified accordingly. With this update, the overall durability of the camshaft system has been significantly improved. 

REVVSUN’s Action:

To ensure the timely launch of the 8mm valve cover kit, REVVSUN’s engineering team collaborates closely with the factory on mold development, rigorous testing and production. All components adhere to OEM specifications, with strict material control ensured through partnerships with Tier-1 global steel suppliers.

• Camshaft

Features:

- Modular manufacturing process  

- Engine-specific bearing steel construction

- Cold-endurance bearing for extreme conditions

Benefits:

- OE-matching strength, appearance and durability

- High surface hardness and superior wear resistance  

- Smooth operation even at -30°C

• Camshaft Housing

Features:

    - Full CNC precision machining

    - Automated fastening with OE-compliant torque specifications

    - High concentricity of the camshaft bores

    Benefits:

- Ensures dimensional accuracy and minimal deformation

- Reduces noise and friction

-Improves wear resistance

- Provides uniform clamping force

- Prevents loosening under engine vibration

• Timing Chain  

Features:

    - Chromium-vanadium carburizing process

    - Oil hole design

Benefits:

- Enhances lubrication and cooling

- Addresses elongation and fracture issues

- Improves Wear resistance over 100%

- Reduces noise 

- Offers 2X higher hardness and tensile strength

• Tensioner  

Features:

- Redesigned internal damping structure

    Benefits:

    - Resolve original design's release force inconsistency

    - Ensure stable chain tension

Through these efforts, REVVSUN has successfully produced and sold significant volumes of high-performance 8mm valve cover kits at a competitive pricing. To date, REVVSUN has delivered over 2,000 complete sets to customers worldwide. For this kit, REVVSUN provides a variety of services, and global buyers can order customized kits (3-, 5-, or 7-piece sets) or individual items in bulk according to their needs.

REVVSUN is committed to providing products that meet OEM standards. If you are interested, please visit our website and contact us.