Originally Posted by lindabarzini
Do diesels really wear out? Since charter catamarans are usually significantly less expensive than private boats, they are enticing to see but they usually have high engine hours.
If a charter boat has 3,000 engine hours, but has been well maintained, is this a concern? If you replace the alternator belt, impeller, water pump, and oil filter are you in good shape?
First - Yes, all mechanical devices are constantly wearing.
Everything else being equal, engine hours is a measure of life expectancy.
Unfortunately, everything is not equal.
It is reasonable to assume that:
1. A marine
diesel engine can run 10,000 hours or more, prior to requiring a major overhaul
2. Age has a detrimental affect on the engine, especially peripheral equipment
3. A well maintained engine will live longer than a poorly maintained engine.
4. A non-abused engine will live longer than an abused engine.
5. Some engine makes/models will last longer than others due to superior design and manufacturing.
6. Some engines of the same make and model will last longer than others, due to metal quality, dimensional tolerances, and conditions at time of manufacture.
As you can see, there are a lot of variables that can affect engine life expectancy, other than just hours.
Take the following scenarios:
1. An engine that has 100 good hours put on it per year will have 2000 hours after 20 years.
2. An engine that has 20 good hours / year on it will also have 2000 hours after 100 years.
3. An engine that has 200 bad hours per year on it, will have 2000 hours after 20 years.
4. An engine that has 20 bad hours on it per year, will have 400 hours after 20 years.
In this scenario, even though engine 4 has far fewer hours, I would pick engine 1, every time!
So what are good hours?
1. Hours run with fresh oil and filter.
2. Hours run where no defects are present.
3. Hours run to 75% full load.
4. Hours run at proper operating temperature.
5. Proper break-in.
6. Proper warm up and cool down.
Due to the nature of charter boats:
1. Operators only care if it works during their use.
2. Operators may not know how to extend life.
3. Maintainers may need to get it back in service before 100%.
4. Increased likelihood of abuse.
I would not expect a charter boat engine to last as long as the engine of an one of a knowledgeable owner with pride of extending proper maintenance
However, the professional service people of the charter company may actually due a better job, than a well intentioned private owner.
Does this help?
Note that engine oil analysis, really only tells the story of the engine oil sample withdrawn.
Oil from an engine due for change, will tell a lot more than oil from an engine just changed.
Oil analysis is not the end all, be all, tell all solution for engine life expectancy.
Clean engine oil today only means it has been recently changed, not that it has been changed at proper intervals (or even at all) over the entire engine life.
Sorry if this sounds self-serving but, well documented records performed by a competent, marine
service provider are a pretty good indicator of how well an engine has been treated.
Ask if any water pump service was ever the result of a failure.
An impeller replaced every 4 years pre-emptively is vastly superior vs one replaced every 2 years as a result of failure and overheating
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