Welcome to the 3.0L SOHC V6 Crank Pulley/Harmonic Balancer breakage page.
This is the way I found the belt on the crank pulley after getting it into the backyard.
In this picture you can see where the woodruff key should be and the metal missing around the keyway for the woodruff key. I don't think any JB Weld is going to fix that.
What caused the damage you see in the above pic? Would you have geussed the pulley itself? If you did your right. As these motors age the chances for the keyway on the crank pulley rounding out a bit because of it being made out of a weaker metal multiplies. What happens is the pulley moves a little back and forth causing wear to accelerate. Early signs of a the problem is usually the timing mark jumping around while trying to set the timing. If it is caught early a new balancer is all you'll need and at worst case a new balancer and woodruff key.
If not caught it is a pretty safe bet the crank will have to be
too. Unfortanatly that is what I'm facing.
Another view of the keyway and you can see a groove going down and around the crank
What can you do to minimize the chance of this happening to you??? Peridoically check the timing to see if the mark is bouncing around(4 to 5 degrees) while being hit with the timing light and if it is take the pulley off for inspection. You could also periodically take the pulley off and inspect it. When inspecting the pulley you want to look for evidance of rounding in the keyway channel. If rounding or any wear is present replace the balancer. When you go to remove the pulley if there is any play in it prior to removing the crank bolt replace it!!! There should be no play!!! If your replacing the pulley double check the condition of the woodruff key and if it has ANY damage plan on doing a timing belt while your at it to replace it.
While the pulley/damper is off remove the pullies off the damper and check the condition of the rubber isolator ring. In the picture below you can see the arrows pointing to the rubber isolator. If the rubber is brittle or has any cracking the damper should be replaced.
Arrows pointing twords rubber isolator ring in the damper assembly
Also any time your doing a timing belt on this motor inspect the
It is already off so why not?
From this side of the crank pulley/harmonic balancer you really can't see any evidence of damage to the unit.
You can see here where the Crank Pulley/Harmonic Balancer was damaged.
Picture of Woodruff key
Picture of Crank Keyway
Picture of Chewed Woodruff Key
Side view of chewed key. Notice how the whole top is shifted on the key.