Hey Mild67,
I've had a few and never had many issues, but there are a few things to be wary of-
1/ the axis of all pulleys must be parallel, biggest culprit being the alt- don't trust the factory brackets, either. I use March billet brackets/mounts and usually have to space things here and there. Sometimes the water pump pulley needs washers between the pulley and flange. I'm guessing the belt was jumping because it was climbing over the alt pulley sides. These set ups must be spot on-orientation wise. (can be hard to eye-ball while the engine is in the car)
2/ I'd say if you're shredding belts the tension is too much. Like I mentioned above, if everything is lined up right, then just screw the tensioner bar/adjust the alt out with just enough weight on it. How much is just enough? Feel/flex the belt on the bottom span and you should move it about 12mm. Run the engine and note the pitch or noise. Too loose will create a kind of vibration, nip it up (turn it off first) in small steps until it sounds just like a blower whine. Normally, the 'loudness' fades the tighter it gets.
Lastly, remember these belts have tremendous 'bite' and you're only driving an alt and water pump, so let the teeth do the work not the belt strain. These setups don't work on the same principals as V or serpantine belts.
Can you post some pics taken fron each side?
Hope this helps-
Cheers
Layne
