In a world where many people consider a diesel engine in a sailboat to be “old” when it has accumulated 4500 hours of operation, our Volvo TMD22 continues to run reliably with 11,000 hours. To put that into perspective, that is roughly equivalent to putting 400,000 miles on an automobile engine. What allows that?
First, of course, is just routine maintenance. Not just oil changes, but all of the procedures that are needed over time. Every thing from cleaning the crankcase ventilation system, to changing the timing belt. These are all listed in your owners manual, but the less frequent procedures are often forgotten or postponed
In addition to the manufacturer’s recommended procedures, there are a few other things that can be done to ensure a long and happy life for your diesel. First and foremost, treat salt water as the serious and deadly poison it is for everything in your engine room. Leaks should be fixed immediately, and throughly cleaned up. Any maintenance work that involves disconnecting hoses, should be done with a wet vac in hand to collect as much spillage as possible before it touches any surface, and any drips that escape should be landing on towels or rags, not expensive engine parts.
Keeping the engine rust-free, clean and painted is not just an esthetic choice, but is critical to spotting small oil and fuel leaks before they become serious. If you expect an engine to be covered with a film of black oil, then it will be. That is not the way an engine should look. All the oil in your engine room should be on the INSIDE of the engine. Not dripping off it, not accumulating in the bilge.
Don’t discount the value of LOOKING. Sailboat engines live in places where we can ignore them. Dark corners of the boat that are hot, loud, and smelly. But just visiting your engine when it is running helps you see and feel what is normal, and when a problem is coming up before it becomes critical. Getting used to what you engine is like when it is running will help you see if it is vibrating more than it used to, making an odd like ticking noise, maybe it is hotter than it used to be, or is dripping fuel, water, coolant, or oil. Even if you don’t know the cause of a change in behavior, any change has the potential to be big trouble. Getting help to get it fixed sooner than later is only for the better. Not seeing these kinds of problems does not make them go away!
As part of our spring maintenance sequence this year we are having the local Volvo dealer replace the timing belt on our engine, as well as checking the compression, and the performance of the injectors. The compression numbers were a bit low, but not at all critical, and considering the age of the engine pretty much as expected. They ranged from 296 to 340 PSI. Minimum specification for a new engine is 304. Two of the injectors have spray patterns that don’t meet standard, and will get new nozzles. All things considered, it is a pretty remarkably good bill of health for a geriatric engine!
Why are sailboat engines so frequently discarded at such young ages? I see a few common reasons.
Diesel engines like to be used. If they sit idle the oil drains down off the various parts, and then starting is very hard on them. Once the metal is dry of oil, it is susceptible to corrosion in the humid world of a boat. Engines that are used infrequently, and for very short periods of time, live a hard life.
Many sailboat have a series of short term owners. If someone is planning on keeping a boat for 2 years, it is very unlikely that they will be doing maintenance that comes up once every 3 to 5 years, especially those larger and more expensive things. Postponed or skipped maintenance will always reslut in a shorter life.
Finally, many engines are condemned and replaced before their time. An owner who has been presented with a series of repair bills for a fuel pump, an alternator, a cooling pump, a leaking fuel system, and a transmission issue might well decide that the easy way out is a new engine, even though the engine itself is fine, and all of the issues are ancillary equipment. This is way more common than it should be, and of course many mechanics are also engine dealers, so they are unlikely to discourage someone who feels that a new engine is the cure for all that ails them.
One of the most frequently cussed at parts of a modern marine engine is the turbocharger. A remarkable invention that basically lets a smaller, lighter engine use less fuel to make more power. Because they are bolted on the engine, it seems that people expect them to be as long lasting and maintenance free as the rest of the diesel. Well, they are not. Turbos last thousands of hours, but they are not forever. Because of the age of our engine, we keep up on what the best replacement engine might be if it ever comes to that. There are a few non-turbocharged engines in this size range, but they are much heavier and much larger than their more sophisticated cousins. I consider the extra maintenance for the turbo to be a good deal for the smaller sized engine block.
A few very small things in the way the engine is operated can make a huge difference in the life of the turbo. Always let the engine warm up before pushing the throttle up. The bearings in a small turbo are not very sophisticated, and absoluetly require a good flow of engine oil to avoid damage. Waiting for the engine to warm ensures that the oil has warmed up and thinned out so it is flowing as fast as it should. Similarly, do not shut the engine down after a run at high speed without giving it time to cool down. Exhaust temperatures in a hard running diesel can exceed 800F. Shutting down the engine when the turbo is that hot removes the cooling effect of the flowing engine oil. The oil remaining in the bearings cooks to a hard, coal-like substance. Always let the engine idle for 5 minutes before shutting down.
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