" Ed,
Liquid water is incom
" Ed,
Liquid water is incompressible, so if there is sufficient amount in a cylinder when the piston comes up during the compression stroke, it will stop the piston, crank and all causing extreme stress on the piston, rod, crank, head, valves, and block. Normally this isn't a problem during cranking as the motor isn't moving fast enough for the momentum to cause damaging stress. However if it fires and then experiences hydraulic lock, most likely something will break.
Another effect is that even small amounts of water in the cylinder during the power stroke will cause additional stress. Water in the cylinder flashes to steam during the ignition. Steam expands much more than a similar amount of heated air causing additional stress on the engine parts. This fact was used at one time in aircraft engines to increase power during take-off and combat. Small amounts of water were injected into the intake air when increased power was needed.
Chuck "