The 931 engine is a modified version of the standard 924 2.0 liter motor. It differs in that it has a different cylinder head, different pistons and a turbocharger. Of course there are other things that have changed to support the operation of the turbo and to harness the extra power that it generates. There are a good many parts that interchange between the base and the turbo models.
Shortly after completing my transmission rebuild I was out for a drive and the timing belt broke. The resulting damage was 3 bent valves, so I decided to go ahead and rebuild the engine instead of just fixing the valves.
The parts I replaced during my rebuild are outlined below, and are listed in this rebuild chart. A more inclusive list of repair parts has additional information.
Clicking on a highlighted item will take you to photos of the work