Ok, so I went off of the information that flash gave me about tensioning the best, which was:
1) You should be able to twist the belt 90 degrees before feeling a lot of resistance.
2) You should be able to press the belt against the timing belt tensioning lever arm without major resistance.
The resulting tension is really just not tensioned, like a slack guitar string. The belt is just relaxed, if you pull on it and let it go, it does not vibrate back and forth.
This is how I tensioned it originally, and there was a loud whirring noise from the belts. I've driven the car about 1,000 miles since in the last month. The noise has stayed the same. I decided to replace the Alt and PS belts, and spark plugs, and figured I might as well pop the timing cover off while it was apart and check the tension of the balance belt. To my complete surprise, the balance belt was slack, like fall off the pulleys slack, like turn it 360 degrees slack. On further inspection, the tensioner pulley had rotated out of place. I aligned the engine to TDC, and found that the bottom balance shaft was still aligned, but the upper shaft was 90 degrees off. This makes sense because the balance belt really can't skip teeth on the crankshaft as it is trapped with the guide, and the lower balance shaft gear is trapped with the idler pulley. When the belt goes slack, this is the only one that has room for it to pop off and skip teeth.
The only information I could find says that I should be turning the tensioner pulley clockwise to tension. This is how I did it the first time, and this is how I did it again. This time I tightened it to 35 ft lbs instead of 33. By the way, even though the tensioner had rotated to it's loose position, the bolt was still tight when I loosened it, I have no idea how the pulley turned like it did...it cracked loose when I loosened it to readjust it. I know it was correctly rotated when I put the car back together the first time, I checked it about 10 times.
Anyway, I adjusted it just the same as before, maybe just the smallest bit looser than original. Now when I turned the car on, the whirring is still there, but not nearly as loud.
So, the whirring was not due to an over tensioned belt, it was due to a massively under tensioned belt. The noise was like an electric motor.
As for the engine vibration, I bought this car and drove it 2,000 miles with the lower balance shaft 1 tooth off, it had probably always been that way. There really wasn't any notable vibration. With the top balance shaft 90 degrees off, the car did vibrate a bit, but not in any distressing way. With it correctly oriented, the car feels very classy. Very little vibration through the feet and hands. It feels like butter.
Anyway, just thought you guys should know, I have no idea why it happened, but I'll be checking it in 1,000 miles to see if it happens again (3 tanks of gas that is as I still haven't fixed the odometer).
-Phil
