You guys that are headed south need to be aware of high sulfur fuel. Fuel sulfur here in the States used to be limited to .1% by law. I think it is now .05%. I have been out of the business for a number of years, and I don't keep up with it anymore. Sulfur is expensive to remove during refining, which is why diesel fuel is now so expensive. When you go south you are probably going to find fuel is much cheaper, but it is not the same fuel as here. It will have a much higher concentration of sulfur in it. You can't tell from the appearance or the way it burns. A small amount of sulfur compounds ends up in your engine oil from ring leakage (blow-by). Humidity causes the engine to get a small amount of water present in the oil. The amount of water is undetectable visually. The water will combine with the sulfur compounds in the oil and produce a weak sulfuric acid solution. The acid solution eats piston rings and just about everything else in the engine. Your engine runs fine on the fuel, and then it is worn out long before it should be.
You combat this problem by running an oil with a high TBN (Total Base Number), and by shortening your oil change interval. TBN numbers are not listed on the containers of oil. You will have to get that information from the oil distributors. It should be on the oil company's web sites. There is an EMA Lubricating Oils Guide Book available, but it is expensive. It lists lube oils by country and it does show the TBN number. I have one that is several years old and probably out of date. This is something to be aware of and plan on shortening your oil change interval. Historically, fuel sulfur concentrations have been pretty high in Mexico and South America.
Any suggestions on duration between Oil changes? 100hrs?
Rich, I believe it's more of a time consideration for oil change intervels when you talk about sulpher. The worst conditions are short running periods where the oil is not hot for long enough to eliminate any moisture. The damage to the engine occurs weather it's running or not.
Just wanted to take this oppertunity to wish you God speed, and looking forward to updates of your trip
S ><)))> <(((><
The required TBN can be calculated if the percentage of fuel sulfur is known. There's the catch. Unless you buy fuel in bulk quantities, you don't get an analysis of the fuel. Capt Sandy is correct in his comments. The main thing is to be aware of it. You may be able to do some research and come up with some sort of figure for average fuel sulfur in the area you intend to go. My EMA Lubricating Oils Data book was publised in 1989. The info in it is probably suspect now. The Caterpillar publication number is SEBU6310. You could call a local Cat dealer and they could give you a price on a new copy or you may be able to get it from an online book seller. It's a very good reference. For instance, if you are in Argentina and want a CD (heavy duty diesel) oil with a TBN of 15, the book lists which oils are available there, the service classification, what viscosities are available, and the TBN number, and Mil spec. I would probably just run a high TBN oil and change it a little early. The higher the TBN, the more resistant it is to the formation of acid. I would think that an auxillary engine in a sailboat would be at high risk from fuel sulfur because of the service it is in. It gets little run time. Every day it warms up some during the day and cools off at night, taking in a little damp air with each cycle.
I found the new version on the Engine Manufacturer's Association website. It has been expanded to include other engine fluids, antifreeze, ect. It is a hundred bucks.
http://www.enginemanufacturers.org/info ... dsbook.asp (http://www.enginemanufacturers.org/info/publications/fluidsbook.asp)
I found the 1989 copy at Barnes and Nobel for 39.99.
The main thing is to be aware that fuel sulfur is an issue when you leave the United States. Seems like I remember that most of Europe has relatively low sulfur fuel. Most everywhere else I would treat as if the fuel has a high sulfur content until I find out different.
High sulfur fuel is a pollution problem. In areas where they are taking action on air pollution, they are reducing fuel sulfur.