1931 model 70 engine vibration

[31model70]

My '31 Chrysler model 70 sedan engine no. V27696, VIN 7997080 has significant engine vibration which increases with engine speed. It stops when the clutch is disengaged at road speed so it does not appear to be drive train related.

The engine has been timed with the dual points synchronized. The belts and pulleys seem to run straight and true. I suspect the problem might be the harmonic balancer which Chrysler calls a crankshaft neutralizer. I started to loosen the six bolts holding the balancer to the crank pulley and, before taking them all out, realized the balancer is split into two pieces. Checking the manual, it seems the balancer halves have a spring loaded clutch mechanism between the halves. Seeing this, I tightened the bolts back up and left it until I can get a better understanding about this device.

Can someone tell me:

1. How does this device work?

2. Could it be the cause of the engine vibration?

3. How is it removed without the springs flying all over?

4. Can it be repaired?

5. Can a replacement be found?

6. Is there another damper which would fit this engine & function properly?

Any information anyone could give on this issue would be greatly appreciated.