Flywheel integrity

yellow rose said
If it’s 15 pounds it’s probably ok. If it’s 30 pounds it better be a low HP tall geared combo.

Says 27 lb, and I have one that's working fine in my decent HP, over-cammed, 3.91 geared combo... and a Lakewood scattershield!

Anyway the OP wanted to know at what point he should discard the cast iron wheel. My recommendation is: immediately.