Water in Cylinder and Oil

[haulnazz15]

Alright, I have a question for the engine gurus. While prepping the engine to go back into the boat after about 2 years of sitting, we changed out all of the spark plugs on the 1976 Ford 351/Merc. The starboard rear cylinder had some water in it, and upon draining the oil, it had water in it as well.

Here's the thing, it was drained via the petcocks on the risers/manifolds before pulling it out a year ago. The water did not have any rust in it, what little I could view of the cylinder walls showed no rust, nor did the spark plug. Is it possible that the water left in the riser just went in through an open exhaust valve while we were lifting/tilting the engine on the hoist getting it into the boat?

I can't imagine that there has enough water left in it to crack the block during a freeze. The boat and engine were in a garage the whole time, so exposure to below freezing temps would have been brief. The water in the oil could have slipped past the cylinder rings.

Engine ran perfectly before removal, and no abnormalities in any other cylinders. Thoughts, suggestions, comments?

 

[haulnazz15]

Re: Water in Cylinder and Oil

The water came out first, then the oil. There was no mixture whatsoever. Oil looked like used oil, not milky at all.

 

[haulnazz15]

Re: Water in Cylinder and Oil

Well, that's all well and good to do the compression tests, but this unit has 750 hours on it, and if it doesn't run right when we fire her up here in a few weeks after hooking everything back up, then I'd probably just do a whole rebuild and have it bored .30 over with all new internals. The leak down/comp tests would only tell me what I'd already know at that point.

I suppose that the comp tests would still tell me the relative health of the engine though.