I had a major front crankshaft seal leak, and that caused the balance shaft belt to come off. The belt was ruined, so I got another one. Today I installed the belt, and just for grins, I left off the covers, fan and radiator, and started it to make sure there was no leaks (yes I installed the crank pulley!). I started the engine, and revved it up from under the hood. When the engine got to about 2,500 RPM, I heard a weird sound and noticed that the balance shaft belt vibrated at the same time. I revved it up again, and the same sound and visual vibration. I turned off the engine and put it back on TDC. I noticed that both balance shaft gears were not lined up with the marks. I can only assume that the sound I was hearing was the belt slipping on the gears. Has anyone experienced this before? Does anyone know what would cause this? Just for fun, I changed out the tensioner with a known good one, and timed up the belt and fired it up again. Same thing happened again. HELP!!!!

Here is a video of the belt slipping. You can barely hear it, but you can definitely see the belt vibrating when it is slipping.
http://s84.photobucket.com/albums/k13/rollguy/?action=view&current=IMG_1112.mp4

Any ideas?

I found the problem today. The lower silent shaft rear bearing is shot:

I think I figured out why. When I had the engine rebuilt, I cleaned all the parts that the rebuilder did not get. The 2 front covers were some of the parts I cleaned. When I put together the counter-rotating gears, I must have not timed them correctly. I compared the shaft to the timing gear with a spare front lower cover, and the two shafts are not in the same spot. That probably caused so much vibration, that it took out the silent shaft rear bearing. I may have to pull the engine again, bummer....

I got it fixed and running!!!

I made a bearing puller/installer and harvested a bearing from a spare block I had:

I pulled the bearing into place with the puller I made:



Bearing in place:

I replaced the silent shaft with a spare one I had. Here is the damaged one:

I got the engine started, and it runs great!

Congrats on the fix. Im terrified to open mine up. It's all magic in there. Unicorn horns, and fairy dust!

You have one with the same problem? Nothing to worry about, it's not as hard as you may think. No magic involved, or fairy dust needed. I originally thought I would have to pull the engine (again) and take it all apart in order to get a new bearing installed. I did not know if it needed to be machined (if so, the entire engine would need to be disassembled), but I thought I would try installing a used bearing first. I am blessed in that it worked, and it was not as hard of a job as I thought it was going to be!

Nono... Mine runs perfectly... Thats why I'm afraid to even look inside there!