Water in Oil

[JOHN COOKSON]

[*]New AntiSiphon loop = new and mounted as high in the galley sink cabinet as possible

It may not have worked.

To my way of thinking since #4 spark plug is wet water could be getting into the engine from the exhaust system.
Let's see what the pressure test reveals.
If there is a water lift muffler or somewhere water collects that is higher than the engine it is easy to get a siphon started. When a warm engine cools it creates enough of a vacuum to start a siphon. Do you have a flapper valve or some sort of a siphon break in the exhaust?
What make and model is the boat? Maybe someone in the forum has a sister ship and can give you some specific advice on the exhaust system.

ex TRUE GRIT

[Elgineddie]

Okay I’m back at the boat and ran a couple pressure tests:

Exhaust manifold: 30psi for 1 hr = no drop; plugged one hose barb and pressurized the other.

Engine block and pump: 30psi for 1 hr = no drop; Closed seacock and pressurized from the thermostat housing. This should test both in-block water jackets and water pump seals. No drop in pressure. Tested it twice.

At this point I’m at a loss and guessing the long crank times and the water in the anti siphon hose may be the suspect. I can put a drain in the low part of the hose leading to the anti siphon loop and just drain it before cold starts.

By the way, she’s a 75 Catalina 30’

[ndutton]

Following those successful tests it's no longer guessing. The only way left for water to get into the oil is up through the exhaust. The question now is why? I propose a thorough examination of the exhaust system is in order from the manifold flange all the way to the transom.

I think I see a Vetus waterlift. Other Catalina 30 members have them without problems so if it is in good condition I think we can rule out a design problem in a C30 application.

Question 1: is the water incursion preceded by sailing, particularly hard on port tack?
Question 2: Is the anti-siphon fitted with a valve at the top or is it an open loop with a hose attached (no valve)?
Question 3: Do you have the exhaust check valve high in the port cockpit sail locker?

[Elgineddie]

Question 1: is the water incursion preceded by sailing, particularly hard on port tack?
No, just in my marina slip. Went from clean oil to milk in my slip.
Question 2: Is the anti-siphon fitted with a valve at the top or is it an open loop with a hose attached (no valve)?
Yes, it’s a new one from west marine with the knob at the top of the loop, a “Marelon® Vented Loop, #903003”
Question 3: Do you have the exhaust check valve high in the port cockpit sail locker? No sir, I do not.

[ndutton]

Hmmm, most perplexing. What's bothering me is although water evidence is reported in #4 cylinder (typical in a manifold or exhaust system water incursion) there is no report of stuck exhaust valves.

If it were me, the next area I'd want to eliminate as a problem is the the hot section (the metal piping attached to the exhaust manifold flange) and the short hose that connects it to the Vetus waterlift. I'd disconnect and remove it for physical inspection. Even if no internal obstruction is found I'd replace it with new because in my mind it's the same work as putting the old one back on. If the old hot section is clear, the Vetus waterlift is next.

In a similar case as yours I may be posting the results of an interesting and as far as I know, a never-been-done-before test in a couple of weeks (the soonest I can get to it).

[ronstory]

Just an idea, but it's pretty easy to do.

I would suggest pulling the small hose off the water injection port of the exhaust stack and check to see where the water level is in the stack. You could use a bit of 1/8" clear air line (like from an aquarium pump). Just remove the hose push in a foot or so in of the cover the end with you finger and pull it out. This will get an idea where the level is in the stack when you start the engine.

If the stack is dry down near the level of inlet of the waterlift muffler... I'm stumped as well.

[Elgineddie]

Can't wait to read it!!

In a similar case as yours I may be posting the results of an interesting and as far as I know, a never-been-done-before test in a couple of weeks (the soonest I can get to it).