Spark knock

K.O. SWINGER said
white smoke to me suggests water entering combustion chamber also would cause knock . I would be suspisos of a bad seal in your manifold gasket ...check plugs for clues

Totally agree with ya there KO

If the smoke disappears it's steam, and if it drifts away it's oil. Sounds like you have an intake leak at the water jacket ports at the very least.

Might want to also pull the oil plug just a little and see if coolant comes out, as it will destroy the bearings in a flash.