GDO Timing Chain Kit 3.5L Ecoboost VVT Cam Phaser

1. Product Overview

This GDO Timing Chain Kit is designed for 3.5L Ecoboost engines equipped with VVT (Variable Valve Timing) cam phasers. It provides the necessary components for replacing the engine's timing system, ensuring proper valve timing and engine operation. The kit undergoes rigorous testing to meet performance standards.

2. Compatibility

This timing chain kit is compatible with various Ford, Lincoln, and Mercury vehicles. Please verify your vehicle's make, model, year, and engine type to ensure proper fitment before installation.

• Ford:
  • 2011-2013 F-150 3.7L DOHC 4V V6 EFI
  • 2011-2013 F-150 3.5L DOHC 4V TURBO
  • 2011-2013 Flex 3.5L DOHC 4V TURBO
  • 2011-2013 Taurus 3.5L DOHC 4V TURBO
  • 2011-2013 Fusion 3.5L DOHC VCT
• Lincoln:
  • 2011-2013 Zephyr 3.5L DOHC VCT
  • 2007-2010 MKX 3.5L DOHC VCT
  • 2011-2013 MKZ 3.5L DOHC VCT
• Mercury:
  • 2011-2013 Milan 3.5L DOHC VCT

Refer to the image below for a visual guide on compatible vehicles.

Image: Compatible vehicles for the GDO Timing Chain Kit.

3. Package Contents

The GDO Timing Chain Kit includes the following components:

• 1 x Primary Timing Chain (254 links - Silent Type)
• 2 x Secondary Timing Chains (50 links - Roller Type)
• 1 x Crankshaft Gear (29 teeth)
• 1 x Timing Guide (Lower, Left)
• 1 x Timing Guide (Lower, Right)
• 1 x Timing Guide (Upper)
• 1 x Timing Guide (Lower)
• 1 x Primary Timing Chain Tensioner
• 2 x Secondary Timing Chain Tensioners
• 2 x VVT Exhaust Cam Sprockets
• 2 x VVT Intake Cam Sprockets
• 4 x Bolts

The image below illustrates the components included in the package.

Image: Contents of the GDO Timing Chain Kit.

4. Component Details

Understanding the individual components is crucial for proper installation and maintenance.

4.1 OE Part Numbers

The kit components correspond to the following Original Equipment (OE) part numbers:

• Primary Timing Chain: AT4Z6268C
• Secondary Timing Chain: AT4Z6268A
• Timing Crank Sprocket: AT4Z6306A
• VVT Cam Sprocket Intake: AT4Z6256A-B
• VVT Cam Sprocket Exhaust: AT4Z6C525A
• Timing Guide (Left Lower): AT4Z6B274A
• Timing Guide (Right Lower): AT4Z6K255A
• Timing Guide (Upper): AT4Z6K297A
• Timing Guide (Lower): AT4Z6K297B
• Secondary Timing Chain Tensioner: AT4Z6K254A
• Primary Timing Chain Tensioner (aluminum): JL3Z6L266A, AT4Z6L266-B

See the image for a visual representation of these parts and their numbers.

Image: OE Part Numbers for GDO Timing Chain Kit components.

4.2 Timing Chain Construction

The timing chains are constructed from alloy steel materials (50CrVa + Pin Shaft 38crMoAL + Sleeve 20crMnMo) to ensure high hardness, wear resistance, and corrosion resistance for long-term durability.

Image: Detailed view of the timing chain construction and material properties.

4.3 Tensioner Types

It is important to distinguish between different tensioner types. This kit includes the AT4Z6L266-B tensioner, which is made of aluminum. The AT4Z6L266-A tensioner, made of iron, is not included and is not compatible.

Image: Comparison of compatible (aluminum) and incompatible (iron) tensioner types.

4.4 Sprocket Features

The sprockets in this kit are designed for precise transmission, good shock resistance, and high transmission power, contributing to reliable engine performance.

Image: Detailed view of the VVT cam sprockets.

5. Setup and Installation

Installation of a timing chain kit is a complex procedure that requires specialized tools and automotive knowledge. Professional installation is highly recommended.

• Ensure the engine is at Top Dead Center (TDC) before beginning disassembly.
• Follow the vehicle manufacturer's service manual for specific torque specifications and timing marks.
• Inspect all mating surfaces for cleanliness and damage before installing new components.
• Lubricate all moving parts with clean engine oil during assembly.
• Verify proper chain tension and alignment after installation.

6. Operating Considerations

After installation, it is important to operate the vehicle carefully during the initial break-in period. Listen for any unusual noises and monitor engine performance. A properly installed timing chain kit will ensure smooth and efficient engine operation.

7. Maintenance

The timing chain system is designed for long-term durability. Regular engine oil changes with the manufacturer-recommended oil type and viscosity are crucial for the longevity of the timing chain and its components. Poor lubrication can lead to premature wear.

8. Troubleshooting

Identifying symptoms of a failing timing chain early can prevent further engine damage.

8.1 Symptoms of a Bad or Failing Timing Chain

• Timing chain noise (e.g., rattling, whining)
• Check Engine light illumination
• Rattle from the engine compartment at idle
• Engine misfire, loss of acceleration, and responsiveness
• Engine turns over but does not start

The image below provides a visual summary of these symptoms.

Image: Common symptoms of timing chain issues.

8.2 Causes of Timing Chain Breakage

• Improper Tensioner Adjustment: If the chain has an adjustable tensioner, it may be set too tight during regular maintenance. Over-tightening can overload the chain, guides, and sprockets, leading to accelerated wear and potential breakage.
• Normal Wear and Degradation: As a vehicle ages, the normal wear and tear of the chain and its components, coupled with the degradation of guides and sprockets, can eventually cause the chain to break.
• Excessive Engine Operation: Too frequent continuous operation of the engine at or near its red line (maximum speed), such as during track events, can cause overheating and excessive wear on the timing chain, rails, and sprockets, leading to breakage.

The image below details these causes.

Image: Primary causes of timing chain failure.

9. Specifications

10. Warranty and Support

GDO offers a 30-day money-back guarantee for this product. This warranty allows for a refund or replacement of your purchase without additional fees if you encounter any issues within 30 days of purchase.

For further assistance or warranty claims, please contact your retailer or the GDO customer support channel provided at the point of purchase.