Noisy metal timing gear cured by torsional damper

[SAJ]

My roadster had a noisy fibre timing gear at idle. See earlier thread https://www.fordbarn.com/forum/showthread.php?t=157518[URL="https://www.fordbarn.com/forum/showthread.php?t=157518"]].
I replaced it with an aluminium gear with no detectable backlash (too tight but all I had at the time). I then got a noise rather like piston slap, but my pistons have .0035 clearance and I only recently rechecked them. Then I realised that the slapping rattles were only as I passed through 1000 rpm 1500 rpm and 2100 rpm (approx, since my rev counter may not be spot on).
This coincides with the "roar" at these revs that many other Model A engines have. So I surmised that the crankshaft harmonic vibration that caused the roar might be shaking the aluminium timing gear and producing the horrible rattle, that makes the normally subdued harmonic roar sound like piston slap from helll
We had a rubber damped front pulley that another member produces, so fitted this.
Suffice to say the rattle is gone, the old torsional wind up noise is undetectable and the motor runs more smoothly up through the gears.
My theory may be wrong but the end result is a great relief. The torsional damper really works well on this engine. I think I will fit one to my wife's Tudor which has a quiet timing gear but a vibration at 2100 rpm too.
I still have a timing gear rhythmic clack at idle, which is not too bad. And changing the fan belt is impossible without removing the front apron and then the spring U bolts and crank handle bush. This is because the rubber mounted damper weight on the front of the pulley is about 3/8 inch thicker than a standard pulley.
SAJ in NZ