The tt
If your harmonics are that bad you have other issues.
The GM factory manual for Monte Carlos states that if the outer damper ring slips, the entire damper loses its harmonic tuning and no longer controls the harmonics, regardless of internal or external balancing. Harmonic dampers are tuned for their engine application. Different engines, even different SBC models have unique harmonic frequencies which the damper must be tuned to match. Sometimes hotrodding an engine can shift the harmonics out of the stock damper's range to control.
Googling symptoms of bad harmonic dampers, some of the results I get are excessive vibrations similar to an unbalanced wheel, uneven RPMs, squealing, and rough idle. On Thirdgen, one guy had a damper that slipped and the harmonics snapped his crank and camshaft. Other guys there reported having rough uneven running cured by replacing bad harmonic dampers. Further searching shows that when a bad damper no longer absorbs harmonics, the harmonics can mimic knocking and make a otherwise healthy gas engine sound like an old 80's diesel about to shake itself apart. That is engines produce tons or harmonics that must be controlled by the damper for smooth operation and avoid fatigue failures. Moreover, harmonic damper issues are often overlooked. The rubber in dampers can dry rot over time and crack from just the passage of time, so its an item that should be replaced in old engines.
I ran a compression test and all cylinders are good and close to each other, smoked the engine and no vacuum leaks. The cap, rotor, coil, spark plugs, and upgraded heated O2 sensor are all new. The choke is working correctly.
