3.5l timing belt tensioner-not to spec after torquing

[benckj]

OK, would be good to see some pics before you button it up. Always nice to have these for reference. The forum is a good place to store these for others to view and comment if something isn't correct.

[disco stu]

Good idea. This is what I've ended up with, using Pauley Faulkners method of tensioning with screwdriver between pulley and mount. Using the 4.4nm of torque method seemed to make it way too tight to get the auto tensioner rod sticking out correct amount. Really don't want a snapped timing belt

While I'm at it with confusing info in the manual-they say to inspect the old auto tensioner by applying ~88+NM to it (or whatever the figure is). How to you apply torque to push the rod in? I'm assuming they are saying to apply 88N of force/pressure, but not real sure. Meanwhile, as we will never be inspecting these auto tensioners in space or on another planet, I think we are pretty safe just using well established kg. I'm assuming the writer hasn't actually understood the difference between Newton meters of torque and Newtons of force. I feel nit picky bringing it up, but I'm doubting any mechanical workshop would have a force meter in Newtons hanging around to use

Note, the rotating tensioner bracket thing on this engine has number 17 visible between the block mounting bolt and roller/pulley

Edit: For some reason the image is rotated 90deg counter clockwise

[DAUMULLER]

Photo 3.8 L set up ( should be very similar )

When I installed mine I used a screw driver blade between the tensioner and the moving metal bracket (shown on photo) that the pulley is mounted on. This is to stop the tensioner compressing to much while you tighten the bolt (could be damaged). Step two was to use cir-clip pliers to tension the belt and while holding the tension on, tighten bolt. If you get it correct you should be able to move the pin in and out slightly. If this happens you can then pull the pin out completely. After the tensioner rod pushes out slightly once the pin is removed this will then be the correct gap. All that is happening is you are removing the slack from the belt and then the tensioner is providing the force to keep the belt tensioned. The gap is an important reference so the tensioner is in the correct position and as the belt stretches it will take up the slack to the correct tension. If the gap is to small it means that the tensioner may become damaged and not travel correctly to tension the belt when required automatically.

[disco stu]

Cheers. The slightly loose pin sounds like what I ended up with

[benckj]

For future reference you can see by the two pics above the different bearing position between the gen 3 and gen 4 models. Although tensioner bearing is same the older model gets tightened CCW rather than CW for the 3.8l.

As described I also adjusted position by feeling the pin removal. Once the pin became loose I secured the bolt and removed pin.

[disco stu]

I also noticed the number 17 stamped on the rotating tensioner bracket on my 3.5l engine from 99 NL. Might possible help some future mug searching for this info

[damo03]

So for the record I installed my tensioner with the pulley two holes facing down on my 1999 6g74 NL. Apart from not being able to use a torque wrench because of the direction, and having to re-do the procedure to get the correct pushing out of the tensioner pin, it all went smoothly.