A family member has an old Corsa 3cylinder GM car, that a previous owner ran with a totally wornout timing chain. The chain was so loose, it rasped a lot of cast aluminium away and produced handfuls of aluminium shavings that circulated in the engine. At least a handfull was removed from the dropped oil pan and shavings were all around the inside of the timing chain cover, camshaft cover, etc. The bearings look badly scarred. Instead of Dexos style 5W30 it now runs with 20W50 oil, and uses half a pint od that every 1000km, but at least it runs and doesn't even smoke.