[MedSailor]

A couple of quick responses....

1. There's no sign of "mustard" or "chocolate milk" oil.....it's clear. I know what that's like. Had a hydraulic lock once with the old engine after a 21 day passage in the trades. Five gallons of chocolate milk in the oil pan. I now start the engine once a day while at sea.

What caused this? Was it a following sea coming in through your exhaust? How did it get in the oil, and how would starting it once a day prevent this issue?

MedSailor

 

[Capt Len]

Only takes a moment for a wave to fill the pipe. Cured by a shut off valve at the transom and/or a drain valve open at the bottom of the system.I have both. Is it possible for a mist from a pinprick ( failing hose or fitting) is getting into crankcase ventilation

 

[smurphny]

While my exhaust has a flapper gizmo, I don't believe these are at all effective in a following sea. I made up some tapered foam plugs for the exhaust with an eye bolt through them that can be stuffed into the exhaust for an offshore passage. I actually bought a shut-off that I was going to install right at the transom but decided I would almost certainly forget to open it at some point in time, or in an emergency, blowing apart the exhaust piping. The foam plugs will just pop out if the engine is started. A string attached to the eye bolt keeps them from getting lost.

 

[MedSailor]

Along the same line of thinking as smurph I was imagining turning the exhaust through hull into a male fitting and putting a loose cap over it much the same way the fishermen with vertical dry exhaust stacks put a tin bucket inverted over the top of the stack. It keeps the rain out and pops right off if the engine is started.

On my new boat my wet exhaust is amidships on the port side. That should eliminate the following sea problem but could pose a problem when hove to perhaps. I guess I should heave to on a starbord tack.

Medsailor

 

[Minnewaska]

......On my new boat my wet exhaust is amidships on the port side......

When motoring, it's usually fairly light wind, which means you create your own apparent wind, usually forward of the beam. Having an exhaust amidships would seem like you're going to get a whiff fairly often.

 

[billyruffn]

What caused this? Was it a following sea coming in through your exhaust? How did it get in the oil, and how would starting it once a day prevent this issue?

MedSailor

For 15 days we had big (15+ ft) swells hitting the stern every 15 seconds. Eventually it pushes enough water up the exhaust to fill the muffler. From there it moves up to the exhaust elbow and then into the cylinders with exhaust valves open. After a while I guess the water in the cylinder makes it's way to the oil sump where when mixed with the oil by boat rocking and rolling the oil looks like chocolate milk.

While it may only take one wave to fill the muffler, my guess is that it takes a bit longer. My theory is that by starting the engine every day we blow any excess water out of the muffler and thereby reduce the probability of water finding it's way into the engine.

The morning of our arrival in Sint Maarten in 2000 we tried to start the engine. Turned the key and nothing happened. We quickly checked the battery and found it OK.

We were lucky that we had one cylinder completely full and so the engine was "locked". Had we had only an inch or less in one cylinder the engine might have started to turn over. As water doesn't compress very easily something would have to give....usually internal parts get bent/break. So, if this is gonna happen to you, pray the cylinder is completely full so the engine won't move at all.

I won't go into all the gory details of how you do the repair, but it's messy and you end up having to change the oil at least three times before all the water is gone. Once all the water was gone, the engine worked well for another dozen years. Only problem the water intrusion is that it corroded the effected cylinders just enough that it eventually caused was a drop in compression in the two cylinders where water got in. By 2006 pressures in these cylinders were down significantly but still above factory spec minimums. The problem was the differences in pressure between cylinders was out of spec.

The engine still worked well and was reliable, but it was wearing out faster than it would otherwise. The other problem the excess corrosion in these cylinders caused was over pressurization of the sump. As gaskets got older the excess pressure started small see pages of oil into the bilge. Oil diapers needed changing regularly and the lost oil needed replacing. A nuisance -- yes, but not a major issue unless you're about to go cruising for an extended period and you don't want to be nursing a 20 year old engine in foreign ports.

That's when you go out and spend a small fortune re powering your boat....so you don't have to be dealing with mechanics whose language you do not speak.

I'll stop there before I start crying again.

 

[dabnis]

Any possibility that the fuel tank vents are allowing salt water into the tank that may be getting past the filter/separator? Curious to know if the analysis shows a little or a lot of salt in the oil?

Paul T

 

[billyruffn]

Any possibility that the fuel tank vents are allowing salt water into the tank that may be getting past the filter/separator? Curious to know if the analysis shows a little or a lot of salt in the oil?

Paul T

Fuel vent is on the stern about 2 1/2 ft above the waterline. Possible, but no water has shown up in the fuel water seperators (there are two between the tanks and the engine fuel filter) and the water alarm in the engine fuel filter has not gone off.

Re quantities of salt (sodium):

Sample 1 with 63 hrs on the oil was ~ 250 ppm
Sample 2 with 215 hrs on the oil was ~ 5200 ppm (end of season, after the crossing)
Sample 3 with 85 hrs on the oil was ~ 840 ppm

First two were by Blackstone, the third by a French lab.

 

[Minnewaska]

Isn't there a gizmo that helps prevent backflow of water in the exhaust, by capturing it at a low point with a flapper inside the exhaust hosing? Perhaps they only work/exist on larger motors with greater exhaust pressure.

 

[smurphny]

Fuel vent is on the stern about 2 1/2 ft above the waterline. Possible, but no water has shown up in the fuel water seperators (there are two between the tanks and the engine fuel filter) and the water alarm in the engine fuel filter has not gone off.

Re quantities of salt (sodium):

Sample 1 with 63 hrs on the oil was ~ 250 ppm
Sample 2 with 215 hrs on the oil was ~ 5200 ppm (end of season, after the crossing)
Sample 3 with 85 hrs on the oil was ~ 840 ppm

First two were by Blackstone, the third by a French lab.

Trying to picture a graph of that, it seems like a large increase from 85 to 215 hrs., more than twice the slope of from 63 to 85. Maybe that's a clue. Is there a normal sodium content of new oil? Is there an acceptable level?

 

[christian.hess]

here is some good info on how to read oil analisis reports:
Stateline Marine Surveyors, James T. Seith, SAMS® AMS® , Winthrop Harbor, Illinois, USA - Understanding An Oil Analysis Report

have you by chance been adding an oil additive? abusing stuff like zddp can and will show up on oil reports and also do damage if used excessively

the height of the vent btw does seem a bit low for the size if your boat....2.5 feet isnt that high up

just a thought

ps. here is a basic answer to your question...
http://www.justanswer.com/boat/4njdi-oil-analysis-indicated-high-sodium-marine-diesel-engine.html

something happened in that second analyis thats a huge spike

almost like you got a big splash in your exhaust and or fuel etc...

you also say its after the crossing which makes perfect sense, a combination of things will get that huge spike...open exhaust tube, vent too low...air intake to close to a source of heavy salt ladden air.

again just a thought

 

[christian.hess]

Fuel vent is on the stern about 2 1/2 ft above the waterline. Possible, but no water has shown up in the fuel water seperators (there are two between the tanks and the engine fuel filter) and the water alarm in the engine fuel filter has not gone off.

Re quantities of salt (sodium):

Sample 1 with 63 hrs on the oil was ~ 250 ppm
Sample 2 with 215 hrs on the oil was ~ 5200 ppm (end of season, after the crossing)
Sample 3 with 85 hrs on the oil was ~ 840 ppm

First two were by Blackstone, the third by a French lab.

the thing with saltwater is its the salt water crystals(after evaporation per se) that do the damage not the liquid unless its enough to hydrolock the engine

 

[dabnis]

Trying to picture a graph of that, it seems like a large increase from 85 to 215 hrs., more than twice the slope of from 63 to 85. Maybe that's a clue. Is there a normal sodium content of new oil? Is there an acceptable level?

Interesting, if I am doing the math correctly, it looks something like this:

1. 4 ppm per hour

2. 24.2 ppm per hour

3. 9.8 ppm per hour

Right, how much is too much?

If there is no water in the separators it appears that some sea water may be coming back through the exhaust manifold system. I would think you would have to have a whole lot of salt water in the fuel for any unburned fuel to contaminate the oil. Don't know much about oil additives, but if they are causing the readings, I would think the readings would be more consistent?

Maybe raising the loop in the exhaust riser, if possible, would help prevent any back flow, if there is any? Or, if possible, install a drain valve in the bottom of the muffler? Maybe a rubber "Flapper" valve/plate over the exhaust outlet?

Paul T

 

[smurphny]

here is some good info on how to read oil analisis reports:
Stateline Marine Surveyors, James T. Seith, SAMS® AMS® , Winthrop Harbor, Illinois, USA - Understanding An Oil Analysis Report

have you by chance been adding an oil additive? abusing stuff like zddp can and will show up on oil reports and also do damage if used excessively

the height of the vent btw does seem a bit low for the size if your boat....2.5 feet isnt that high up

just a thought

ps. here is a basic answer to your question...
http://www.justanswer.com/boat/4njdi-oil-analysis-indicated-high-sodium-marine-diesel-engine.html

something happened in that second analyis thats a huge spike

almost like you got a big splash in your exhaust and or fuel etc...

you also say its after the crossing which makes perfect sense, a combination of things will get that huge spike...open exhaust tube, vent too low...air intake to close to a source of heavy salt ladden air.

again just a thought

Am getting an "Account Suspended" message screen on the first link.

Right about additives. I know some top oil co. engineers who advise against any additives. Their contention is that the stuff has already been engineered by scientists that have been doing it for decades and have added all the ingredients needed to optimize its function.

 

[christian.hess]

hmmmmmmmmmmmm

 

[MedSailor]

The thread is leaning heavily towards sea water as the cause while coolant seems more likely to me.

BTW I wasn't kidding about using highlighter ink to improvise blacklight die. Add it to your cooland and if it shows up in your oil you know exactly what is going on.

Medsailor

 

[christian.hess]

potassium is the clearer indicator of a coolant leak

but if you read back on the first pages most of us went with coolant leak too...simply because of that one overheating incident that can or could lead to a slight pinhole of the head gasket or a pinhole leak in the heat exhanger etc

also the water pump if its shaft driven

honestly there are still many possibilities

HOWEVER when one does an "ocean" crossing" and after that one seas a spike, a heavy spike in sodium its hard to not tackle that first, versus say looking at the engine side of things

anywhoo

 

[pdqaltair]

While I'm sure I may have missed some posts, I am in the coolant industry....

Was the oil tested for glycol? I would question the qualifications of a lab that did not suggests that after suspecting leakage. The problem would have been quickly identified.

What coolant was used? It would be a simple matter to test the coolant and determine if the ions were moving upwards in the same pattern.

Potassium is NOT a sure indicator. It is used in some oils and not used in most coolants. You need to know what the starting point of each was.

It is not surprising that there is little water in the oil; it will boil out. But the glycol will not.

 

[billyruffn]

UPDATE:

When we arrived in Lagos, Portugal I invited yet another Yanmar mechanic aboard for a consult and another oil analysis in a local lab, results of which aren't back yet.

Since the last oil change I've stopped using the Gori overdrive and have been tracking the coolant level religiously.....in 50 hrs we're down only 1-2mm in the overflow bottle. The mechanic says that's not unusual.

Conclusion: it's not a coolant leak.

If it isn't coolant, it's got to be seawater. There are three sources of seawater: the oil cooler, the air cooler and the exhaust system. We tested the oil cooler and it's good. That leaves two possibilities.

The mechanic in Lagos took a hard look at the exhaust system and he thinks the problem may lie there. I have since done an analysis of the volumes of the hose runs and the muffler and have reached the conclusion that he's probably spot on.

When the new engine was installed it required that we increase the size of the exhaust lines from 2.5 to 3 inch hoses. The larger hose was stiffer and required installation of hard fiberglass elbows in a couple of places where the turns were tight. With those exceptions, the general layout of the old exhaust system was followed in terms of the hose runs.

Exiting the exhaust elbow we now have a 90 deg elbow and then 20" of hose to the water lift muffler (side in, top out). We have a 28" vertical rise coming out of the muffler to a 90 deg elbow and then a 5+ ft horizontal run aft to the steering compartment where the hose loops up to the top of the space and then drops to the exhaust port on the transom. In all, there is probably 9-10 feet of hose between the top of the muffler and the highest point in the exhaust hose run plus the ~ 2 feet between the exhaust elbow and the muffler.

The new engine was actually smaller than the old one (despite the ~2x HP) and so the height differential between the exhaust manifold and the muffler has decreased by a few inches, and due to the new 3" very stiff hose we need for a 90 deg. elbow immediately below the exhaust elbow -- all of which means that the angle of the hose running to the muffler is much shallower than with the old engine. My estimate is that it's a 8-10" drop from the exhaust manifold to where the hose enters the muffler, and that the hose is 10-15 deg off horizontal.

Less height differential + shallower angle = higher potential that we end up with seawater in the hose between the muffler and the engine IF the muffler fills with water when the engine shuts down.

Enter the new 3" hose -- larger diameter = greater volume of water in the hose and greater chance that the muffler has more water in when the engine shuts down.

Based on the calculations I've done of the volume of the hoses and the volume of the muffler, and using assumptions for the gas to water ratio in the hoses provided by Centek and Vetus tech support (Estimates range between 25 and 50%)....I've come to the conclusion that the muffler is overfilling (it should be no more than 1/2 full after shut down according to the tech guys).

Over filling the muffler puts standing water in the hose between the engine and the muffler when the engine is shut down. Now put the boat in a big following sea like we had crossing he Atlantic last summer and you now have water sloshing about in the pipe between engine and muffler with the potential for a few sloshes pushing small quantities of water up to the top of the exhaust elbow and into the exhaust manifold and from there a few drops get into the cylinders with open exhaust valves. It doesn't take a much water to register ppm of salts the oil. It's certainly not enough water to interfere with the starting of the engine. And, of course, once the engine starts the few droplets of salt water are immediately evaporated within the cylinder and hence no sign of foreign liquid in the oil.

So, the current hypothesis is the salts are from seawater entering the engine through the exhaust due to overfilling of the muffler, caused to long hose runs and larger hose.

With the approach of the fall season I need to move the boat further south and so we will not have time to address a redesign of the exhaust system before moving on from Portugal. We're moving on to Morocco next week (only 200 miles) where tech support and suitable parts are probably in short supply. We have some down time in Morocco and , my interim solution will be to install a small ball valve in lower part of the muffler which will enable me to drain the muffler into the bilge after shutting down the engine when at sea. I'm also going to install a flapper on the exhaust as a preventive measure until we sort the entire system out.

We will run with these two changes to the system and continue to change the oil every 50 hours until we can be sure that we've found the problem. My guess is that draining the muffler following every engine shut down will solve the problem....but that remains to be seen.

Stay tuned.

 

[Delta-T]

UPDATE:

The new engine was actually smaller than the old one (despite the ~2x HP) and so the height differential between the exhaust manifold and the muffler has decreased by a few inches, and due to the new 3" very stiff hose we need for a 90 deg. elbow immediately below the exhaust elbow -- all of which means that the angle of the hose running to the muffler is much shallower than with the old engine. My estimate is that it's a 8-10" drop from the exhaust manifold to where the hose enters the muffler, and that the hose is 10-15 deg off horizontal.

If I am reading this correctly, you have no riser connected to the exhaust manifold? I made this same mistake when I replaced my exhaust system. Last year I added the riser and have not had an issue since.

This is before with no riser:

And this is the modification: