Installation Tips


Cloyes Tech Tips: Ford 3.5L / 3.7L Duratec Timing System Replacement

Secondary tensioner installation and activation

For Ford 3.5 and 3.7L DOHC V6 engines, the automaker made multiple variations of this timing system throughout production. Some engines used a roller style primary chain, some an inverted tooth primary chain; some engines have two VVT phasers, others used four VVT phasers; some had internal water pumps, and others used external water pumps. On top of that you have NA and Turbo engines installed in both FWD and RWD platforms. But no matter which engine variation you have, the timing installation procedure is very similar.

In its technical installation video for the Ford 3.5 and 3.7 engines, commonly known as the Duratec or Cyclone engine platform, the Cloyes technical support team demonstrates proper installation instructions as well as shares critical installation tips to ensure the job is done right the first time. Since Cloyes offers a number of kits and components for these engines, it is crucial the correct kit or components are used.

During the installation process, the installer must be aware of the unique design of the secondary timing chain tensioners. Similar to most applications, the secondary tensioners come with a clip that must be removed after installation, but unlike other applications the removal of the clip does not activate the tensioner. The clip simply prevents the tensioner from being compressed and activated while being installed into the cylinder head feature.

Once the tensioner is properly installed the clip can be pulled, the cam sprockets and secondary chain are installed, THEN you must activate the tensioners.  You do this by pressing on the chain allowing the tensioner plunger to fully compress and release. This activates the internal spring and allows the tensioner to extend and apply pressure to the chain. Failure to manually activate the secondary tensioner(s) can lead to catastrophic engine failure. Once the tensioners are activated there is no way to deactivate them.

Once installed, the clips are removed, and when ready, the tensioners must be compressed to activate. Once the tensioners are activated there is no way to deactivate them.

To install the secondary tensioners, apply some oil to the tensioner housings, the O-rings, and the cylinder head bore features. With the installation clips in place, insert the tensioners into the bores, with the curved side of the contact pads to the back, and push them in until they are fully seated. Then install the lower chain contact pads by sliding them in from the front. Once fully installed, pull the installation clips but be careful to not compress the tensioners. The secondary chains need to be installed before activation. You can see the video in its entirety at

As always, we want to remind you that chains can experience wear and stretch, guide contact surfaces can become damaged and guide bracketry can break, damage to the tensioners can occur, and sprocket tooth wear will develop when operating with an unstable chain. For these reasons, and the fact that timing component cost is a fraction of the labor costs required to replace the components, it is recommended to replace all components when making the repair. In doing so, the consumer and technician can save time as return visit may be prevented; the vehicle owner will save money in the long run as opposed to having multiple components replaced at different intervals; and the technician and shop can reduce comebacks thanks to all components being replaced at the same time.