Nanni 2.50 water in oil

[davewa]

I have just installed a brand new Nanni Diesel in my Slipper Launch and to my horror after 3.8 hours I've dipped the oil and I find that it's emulsified. I've pumped out a small sample and there's definately water in the oil. The engine has only been run on the one occasion and was running sweet. I'm convinced that the layout of of my exhaust and water lock system is fine, it certainly complies with the drawings from Nanni and everything else I've read. The engine started with very little cranking and obvioulsy wasn't hydraulicing so I'm convinced the water couldn't have entered the crancase through the exhaust. In any case surely water coming in via this route would end up in the cyliners resluting in catastrophe.

Has anyone experienced similar problems in the past and if so what was the cause? I should be covered by the warranty but this problem has ocurred before the first service/inspection which should completed before the first 20 hours/45 days. I'm concerned that I've overlooked something in my installation and/or the manufacturer might try top claim I'm not covered.

The freshwater coolant level is a little below the brim (say 1/2 inch) but I don't know what level it was before I started so can't say for sure if it's gone down. Does anyone have experience of these engines do they have any known weak points in the cooling system sealing where cooling water could enter the crankcase?

I suppose the water could have been there before I started??

Until now I'd only read good things about Nanni, and the Kubota engine on which it's based.

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[sailorman]

"by brim" wot do u mean?
i have the 4150 that has a car type expantion tank with a "level " line apporx 1/2 way up the body.


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[TrueBlue]

I can't offer you any definitative advice, other than to say that the base Kubota engine is very rugged as they were designed for industrial use including builders' equipment.......

I have fitted a Beta version in my nb: and it takes all sorts of punishment. Your best option is to shout for help to the supplier (if you have not already done so).

You could have a faulty unit - not everything is perfect, but the apparent loss of coolant - as you describe is 'normal' as the fluid expands when it gets hot and if you have not fitted an expansion bottle the excess will have gone overboard or into the bilge.

I would be inclined to see if there is any pressure in the cooling system; try removing the filler cap - BEFORE the engine gets warm, and at tickover see if there is any pressure (blank off the overflow tube first) and put your hand over the cap hole. If there is then exhaust gas is getting out somewhere; which means that water could get into the sump when the engine cools down.

If your wet exhaust system was faulty, the engine would have 'hydrauliced' by now.

If there is any delay / arguments in getting the engine fixed, I'd be inclined to change the oil pronto and not run the engine as the emulsification will lead to gunge which may block the oilways.

Hopefully ano will read this post and correct me if wrong.

As you have a slipper launch I assume you'll be on the Thames so not too far from knowledgeable assistance.

Not very specific, I'm afraid but it might get the conversation going.

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Stop what you're doing and wait my signal

 

[davewa]

Sailorman - Not sure why I didn't get an email when you responded. Anyway, no expansion tank on my engine. The freshwater filler (pressure cap) is in the top of the heat exchanger and the coolant level is 1/2 inch below the rim (brim) where the spring loaded seal in the pressure cap sits. Above the rim there's just an overflow pipe that vents into the bilge. Or in other words the config is just like car radiators used to be before expansion tanks were fitted except for rad read heat exchanger. So the 1/2 below this brim is entirely consistent with the expansion that TrueBlue describes. The freshwater system halds 2.5 litres and the 1/2 inch probably accounts for 5-10% of this, I guess I could work out if thes degree of expansion is correct for a temp change of water/antifreeze between 20C and operating temp or maybe somebody knows if this feels about right.

TrueBlue - I've already pumped out the oil and replaced with clean, my guess is that theres perhaps 25mL of water that has settled out in the oil I've drained. It's booked in at a Nanni Agent on Monday. I've already tried to asess if the cooling system is pressurised, basically by starting the engine from cold and removing the pressure cap after about 30 secs, at this point there's no sign of any pressure build up. My guess is that the pressure cap holds about 10 PSI so I'd hear any pressure escaping. I suppose if there was a problem above a piston (head gasket or cracked head) it would pressurise the cooling system but if there were a problem lower down (porous block casting, leak around the O Ring at the base of a piston liner or maybe a crack in a piston liner below the piston rings then the cooling system would probably not pressurise)

Anyway, thank you both for your responses. I'll update again once there's a clearer diagnosis and hopefully a solution. Maybe it's just condensation.

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