Various Harmonic Balancers were used over the years. No clear information on what the differences are.
|Model||Years||Part number||Color||Engine number|
|S2/S3/S4||1983-1989||9188.8.131.52||orange||M28.19/20 M28.43/44 M28.45/46 M28.41/42|
This is the S4 vibration damper (GT/GTS are green). Notice the TDC marker and the -2 degree, -1, 0 +1 and +2 degrees mark
Damper with the Porkensioner fitted .... and what the damper should look like in your car.
This is what it looks like when the damper is placed reversed.