Lower Balance Shaft Won't Turn When Tightened

[barnwerks]

The "race" does not spin relative to the balance shaft when assembled. It provides the rearward thrust surface as well as the radial sealing surface. It is locked to the balance shaft by compression of the component stack against a shoulder at the forward shaft end.
The same design is utilized for the axial control of the camshaft.

[barnwerks]

The last thing I discovered last night is if I assemble everything without the thick gold washer on the pulley, everything works fine and I can spin by hand with it tightened down. The second I put that washer on there and tighten it down, it's no bueno. I'm not sure how that's even possible, maybe without the washer it can't push tightly enough against the pulley, who knows.

While we're solving the mysteries of the (your) world...
I'll suggest the reason the assembly was still able to spin when tightened without the washer is that the bolt was bottoming out in the threaded bore and not actually applying force to the pulley and race.

[Deemar]

Thanks, I'm trying to track down a bearing press to move it back in. I'll report back.

[944er]

I did notice in the PET that the upper and lower bearings have different part numbers. Just a thought.

[Deemar]

The axial positioning of the balance shaft is controlled completely in the front housing. I suspect the bearing insert sleeve in your front housing may be overhanging toward the front and binding on the rear flange of the race when the pulley is tightened.

That was it, you did it! I don't have a bearing press so I used a pulley puller in reverse and pushed the bearing back down a millimetre. I reassembled everything, tightened the bolt on the shaft and everything spins great now! Thanks!

Still no idea why the shaft won't spin while pulling on it but maybe I don't need to worry about that right now. Thank you very much to everyone helping me.

[Tom]

The axial positioning of the balance shaft is controlled completely in the front housing. I suspect the bearing insert sleeve in your front housing may be overhanging toward the front and binding on the rear flange of the race when the pulley is tightened.

That was it, you did it! I don't have a bearing press so I used a pulley puller in reverse and pushed the bearing back down a millimetre. I reassembled everything, tightened the bolt on the shaft and everything spins great now! Thanks!

Still no idea why the shaft won't spin while pulling on it but maybe I don't need to worry about that right now. Thank you very much to everyone helping me.

That's fantastic! Congrats on sticking to it! Big hats off to @barnwerks for his spot-on suspicion! Wish I had thought of that, but I thought we were on to something when you couldn't spin it when pulled forward. Carpokes is a newer and smaller forum, but the amount of 944 knowledge here really is second to none, and it comes with a much lower noise to signal ratio than most places too! Tell your friends!