Mine was only running 1 & 2 and this turned out to be a headgasket failure.

The white smoke would indicate water vapour and as somebody has allready pointed out the S1 is not a water cooled unit so I think you can rule that out. My money would be on headgasket failure. Valve stem seals failing would allow oil into the combustion chamber not water so the smoke from that would be blue.

Do another compression test and post the results on here mate.