I am perplexed, diesels in highway trucks can and do run without major overhauling for several hundred thousand miles, yet marine diesels don't seem to. I would think , especially in fresh water environment, that they should last longer than I'm reading about. At 4mi/hr, which equates to say 40,000 mi in 10,000 hr, it should be just broken it, yet I never read of running hour figures this high.What gives? What is a high eng hr #? Thanks May move to a 30 someday.
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Randy
I'm no diesel expert, but have enjoyed them for years in my cars, and recently in my newly purchased 84 C-27. While I believe that marine diesels can be as long lived as automotive and truck diesels I think there are two keys: The first is maintenance; without it, no diesel, large or small, will run a long time. Diesels are hard on their oil, and frequent oil and filter changes are a must. Cooling systems also need to be kept clean, and the coolant changed periodically to prevent overheating. Of course, there are loads of other maintenance jobs specific to each make and model that need to be carried out. The second factor in my experience is the actual amount of usage an angine gets. It seems that an engine can run a certain number of hours in its life, but can do it over a certain number of years. In other words, an engine that is used frequently and for long trips may run several thousand hours over a given period. One that is used infrequently, or for short trips, may actually be in worse shape after the same period. Just sitting is hard on any engine, including a diesel. Belts and hoses deteriorate, fuel gums up or becomes fouled with algae, cylinder walls corrode in the salt air environment. In contrast, the engine that has run regularly for lengthy times has been well lubricated, the heat from operation has burned off contaminants in the oil, and (hopefully) the owner has inspected the engine prior to each startup, as well. Truck diesels are started, run all day, and sometimes all night, for days on end. Many sailboats are started, backed out of the slip, then sailed, never allowing the diesel a good workout. I believe there is nothing better for an engine's life than good maintenance coupled with frequent usage. Randy
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Jon
Interesing Website
There are some interesting opinions on diesel engines at this site, http://www.yachtsurvey.com/
There are some interesting opinions on diesel engines at this site, http://www.yachtsurvey.com/
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Gene Foraker
Your Assumptions are wrong
The way I figure it, a car engine might compare to an average 50 mi. per hr. of engine time in a car for one hr. of engine running in a boat. Yes, much car time is at idle and at lower speeds, but because of different gears, the rpm's will still be up there at lower car speeds. Also, you don't run the car engine for hours at 75 to 80% of max rpm's. I could argue an even higher equivalent car speed. Using 50mph at 100 hrs. you would get 5,000 miles which maches pretty well for reccomended oil changes in both car and boat. 1000 hours on a diesel would be the equivalent of 50,000 miles on a car.
The way I figure it, a car engine might compare to an average 50 mi. per hr. of engine time in a car for one hr. of engine running in a boat. Yes, much car time is at idle and at lower speeds, but because of different gears, the rpm's will still be up there at lower car speeds. Also, you don't run the car engine for hours at 75 to 80% of max rpm's. I could argue an even higher equivalent car speed. Using 50mph at 100 hrs. you would get 5,000 miles which maches pretty well for reccomended oil changes in both car and boat. 1000 hours on a diesel would be the equivalent of 50,000 miles on a car.
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Dick Keenan
The best example of how long a Diesel can go in a proper environment is in a full-time-use electrical generating plant. If a Diesel is running 24/7 at a constant speed, with oil and filters changed by turning valves, it will run for ever and ever (almost). There's no stress from warm-up/cool-down cycles or torqueing up and down. No lubricants or fuels get "old." The hardest time on any engine is at cold start and boats do lots of those. Especially after sitting idle for a long time, which boats also do a lot of, usually in the worst or all environments. When sitting, the oil left on sensitive machined parts evaporates, congeals, or sinks to the pan, leaving those parts exposed to air and whatever corrosive chemicals are in it. I've also found that when changing oil, especially in small engines on sailboats, it's practically impossible to drain all of the old oil, which means that even after a change, yo're still left with some amount of contamination when compared with a car or some other location where you can get to the drain plug underneath.
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patrick e boole
the difference
i have the same engine in my kabota tractor that is in my 27 cat. my 30 has the 3 cylinder one. the only difference that i can see is the amount of constant use that my tractor gets. i am ashamed to say that i can't remember the last time i changed the oil in the tractor but it gets a few hard hours use 7 days a week. i have talked with my mechanic, and i also have to say i can't remember when i had to have anything done to the tractor, and he says that you need to put a load on the engine to make sure the fuel pump gets properly lubricated. when in dock when i run the engine i secure the docking lines and run it in reverse and foward. i wish i knew the difference cause the enviroment that i run the tractor is about as bad and the sea enviroment. i think we just tend to baby the boat engine more and it needs to be worked harder and more frequent. so what say guys lets keep the sails covered this weekend and motor the heck out of it.
i have the same engine in my kabota tractor that is in my 27 cat. my 30 has the 3 cylinder one. the only difference that i can see is the amount of constant use that my tractor gets. i am ashamed to say that i can't remember the last time i changed the oil in the tractor but it gets a few hard hours use 7 days a week. i have talked with my mechanic, and i also have to say i can't remember when i had to have anything done to the tractor, and he says that you need to put a load on the engine to make sure the fuel pump gets properly lubricated. when in dock when i run the engine i secure the docking lines and run it in reverse and foward. i wish i knew the difference cause the enviroment that i run the tractor is about as bad and the sea enviroment. i think we just tend to baby the boat engine more and it needs to be worked harder and more frequent. so what say guys lets keep the sails covered this weekend and motor the heck out of it.
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Charlie
I agree with Bill
I have a friend with a cal 38 who does a lot of crusing> His engine has just over 6000 hours and no problems. Salt enviornment, fresh water cooled. the trick is to maintain it. Charlie
I have a friend with a cal 38 who does a lot of crusing> His engine has just over 6000 hours and no problems. Salt enviornment, fresh water cooled. the trick is to maintain it. Charlie
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