I was starting to build up my collision damaged 95 4Runner with donor parts, when I discovered this:


The belt has about 30 K on it, and the rest of it is well used, but not worn out in any way.
The only thing I can figure is that some loose little hardware bit floated under the belt, got trapped, and punched the hole on the subsequent revolutions.
I installed the belt 9 years ago when I rebuilt the motor, so it appears that this little fiasco is on me for not being more careful during assembly.
I had the front of the engine clear with the radiator out, so I figured I'd look at the belt while it was easy to do.
Lucky that I did. This belt was put on while the motor was on a stand, so relatively easy
Now I get to do the crank and cam bolts while it is in the car. Let the fun begin.
My collision repair schedule has gone in the dumper.

Art

 

On the interweb that's called "TB performance mod": hole reduces belt's moment of inertia by 0.578964 Kg.m2---> engine outputs 19.748 more horse powwaa...all calculated

 

Check your gears for damage. That piece of fod might still be in there some where.

 

The piece of flotsam was found in the space beneath the crank pulley.
The cam pulleys seem OK, but the crank pulley has some wavey teeth.
Lesson Learned!!!

Art.

 

Picture of the crank sprocket?

 

Hard to see in a photo, but there is a wear spot ring around the sprocket.
Also some teeth look slightly mishapen, or could be my imagination
I have a low mileage extra sprocket that'll replace it.
Thanks for the interest.

Art[

QUOTE=scope103;52424699]Picture of the crank sprocket?[/QUOTE]