belt moving and sliping

Hello - I hope that you can help me!

I'm living in Switzerland. Last week I runed first time my '96 Mustang Cobra with the V2-SQ /w aftercooler. I replaced the 3.6" charger-pulley and used the new 3.25" that was included in the vortech aftercooler-package.

So - after 150 miles - the belt moved over one groove on the charger-pulley (to the front of the car) and it moved over two grooves on the water-pump-pulley.

I checked the alignment of the pulleys - but it seems to be o.k.


What can I do?

Thanks Mike

Mike,
I am not a mechanic. However, I have watched belts being installed many times. From what I know your alignment is off somewhere. We usually get the belt on and then have someone start the car while we watch (in line with the belt which means off to one side) for the belt to jump. You can usually see which pulley is causing the belt to jump. Then you start to shim with washers to get the alignment straight. Looking at the pulleys without the motor running will not do it. A pulley does not have to be off much to cause a jump. If it does not jump on start up then rev it up.