Various Harmonic Balancers were used over the years. No clear information on what the differences are.
Model | Years | Part number | Color | Engine number | |
928 | 1978-1979 | 928.102.120.14 | black | M28.01 | |
928 | 1979-1983 | 928.102.120.15 | red | M28.11/12 | |
S | 1981-1983 | 928.102.120.16 | blue/green | M28.11/12 | |
928 | 1980-1983 | 928.102.120.17 | grey | M28.09/10 | |
S2 | 1984-1985 | 928.102.120.22 | ? | M28.21/22 | |
S2/S3/S4 | 1983-1989 | 928.102.120.23 | orange | M28.19/20 M28.43/44 M28.45/46 M28.41/42 | |
S4/GT | 1990-1991 | 928.102.120.23 | black/grey | M28.42/47 | |
GTS | 1992-1995 | 928.102.120.24 | green | M28.49/50 | |
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.