Mercruiser reversion

[YELLOWSS]

Chevy 406 nothing radical. Pump gas motor, about 425hp. Edlebrock aluminum heads, and intake. Hydraulic cam. 495/228 duration lobe separation 111. Imco aluminum thumper exhaust wet. 4” through transom exhaust. It has rubber flap. My question is I have a roller rockers, and a poly lock came loose on the intake valve. I noticed I had a dead miss, so I pulled the plugs. I felt a couple water drops on my finger when I pulled one plug. I checked the oil and it was milky. I ran this set up all year with no reversion. I pulled the exhaust on that side, and riser gasket and seals were perfect. I filled the exhaust manifold up with hot water, and heated it through the exhaust hole with map gas. No water drops anywhere. I pulled the intake to make sure wasn’t leaking from the water jacket. Number 2 is getting water. I don’t see any issue anywhere except the rocker arm. Could this cause water to get in that cylinder?
thanks in advance.
Roy

[FMP]

Loosened up enough to change the valve timing enough to create the problem or maybe wiping the cam too?

[YELLOWSS]

Loosened up enough to change the valve timing enough to create the problem or maybe wiping the cam too?

The poly lock back all the way off, and the push rod came out of the lifter, and rocker. The valve wasn’t opening at all. Cam is fine

[FMP]

How many hours running before it walked out completely

[YELLOWSS]

Proly 20 hours. Then the water was in the cylinder and oil. Trying to confirm if the cylinder doesn’t have the compression from the valve not opening, if this could cause reversion in that cylinder.

[FMP]

Water in reversion or gasket or a crack. If you think it's good bearing and cam wise change Oil a couple times and run it?
Oil rings water cylinder walls, how long before they get it from water oil?