What are the timing marks for a 1990 Geo Prizm?

Timing marks 1990 GEO Prizm GSI (4 AGE)The crank timing mark for the 1990 GEO Prizm GSI (4 AGE with twin overhead cam) is a notch found on the inside rim of the crank pulley. Set this notch to 0 for TDC on the Crank sprocket dust cover.

The intake and exhaust cam sprockets have an indention on one tooth of the sprocket. Aline this dot with the crease in the back plate. The intake crease is a vertical crease at 12 oclock position and the exhaust is a vertical crease slightly before the 12 oclock position.

If cam sprockets have been removed make sure you align the cam shafts before reinstalling sprockets. Set the knock pin of the intakse shaft to the 12 oclock position and the exhaust shaft to the 5 oclock position. Once this is done install the sprockets so their respective timing marks line up with the marks on the metal back plate.