Diesel Engine Design Life

[Norman_E]

I have lifted this post by KellysEye from the "Emergency Electricity Supply" thread.
Out of interest what type is the engine and how old is it. Modern engines have design life of 8,000 hours and are generally reliable. Will it be serviced for the passage and will he carry spare filters for the engine and fuel line? It also worth carrying a spare alternator and fan belts, plus any other belts if there are any. If the engine is relatively new and those things are carried he shouldn't need an alternative power source. If he has an old engine such as the Volvo MD series they didn't have a design life at all just needed servicing and new pistons and rings if burning too much oil. We had one and never had a problem with it nor did the previous owner.
Read more at http://www.ybw.com/forums/showthrea...electricity-scource/page2#yjJUQZeW1oAJztOI.99

I am wondering just which modern engines actually have a published design life. My own Yanmar 4JH2 DTE dates from 1998 and has done over 4500 hours. Is it a "modern engine" designed with a specific lifespan?

 

[sailorman]

when i re engined 13 yrs ago with a Nanni 4150 i asked a few plant operators about these Kubota engines, they had engines with 6,000 hrs with only routine servicing ever done. no major defects

 

[RichardS]

I have lifted this post by KellysEye from the "Emergency Electricity Supply" thread.
Out of interest what type is the engine and how old is it. Modern engines have design life of 8,000 hours and are generally reliable. Will it be serviced for the passage and will he carry spare filters for the engine and fuel line? It also worth carrying a spare alternator and fan belts, plus any other belts if there are any. If the engine is relatively new and those things are carried he shouldn't need an alternative power source. If he has an old engine such as the Volvo MD series they didn't have a design life at all just needed servicing and new pistons and rings if burning too much oil. We had one and never had a problem with it nor did the previous owner.
Read more at http://www.ybw.com/forums/showthrea...electricity-scource/page2#yjJUQZeW1oAJztOI.99

I am wondering just which modern engines actually have a published design life. My own Yanmar 4JH2 DTE dates from 1998 and has done over 4500 hours. Is it a "modern engine" designed with a specific lifespan?

Don't worry, that assertion by KE has been repeated many times and rejected by the majority of forumites on every occasion.

Richard

 

[Concerto]

More engines are ruined by lack of use and poor maintenance than over use.

 

[dom]

I am aware that some OEM manufacturers (for example Yanmar, Atlas Copco, ABB, etc) provide guidance as to the period their equipment can be run in industrial applications without a significant likelihood of wear beyond the normal consumables. My understanding is that most components are designed to tolerances likely to last far longer than this guided minimum, which should in no way be interpreted as the "design life".

PS: One should always take 8,000 hour guides with a pinch of salt - there are 8,760 hours in a year of continuous operation!

 

[vyv_cox]

Some years ago a TV motoring show, possibly Top Gear in a previous version, tried to find the Mercedes car with the highest mileage. A taxi in Egypt was found with more than 1,000,000 miles on the clock, equivalent to 25,000 hours at 40 mph. Several others were found with mileages approaching that, mostly on the original engine.

 

[Tranona]

8000 hours is the often quoted life for the small industrial engines that are the base for most yacht engines. This equates to about 50 years in typical yacht auxiliary use. However actual life depends on how it is used. In a piece of industrial machinery such as a digger or a refrigeration plant it will be run for long hours at a time with regular changes of oil and filters and that life is easily achieved.

Contrast that with typical yacht usage where the engine might run for a short period at the beginning and end of a passage and then lay idle for long periods. much of running is not at full load and the engine may not reach operating temperature. so, not unusual for engines to give trouble at less hours - not the basic oily bits but things like cooling systems and exhausts, both commonly featured in threads here on engine problems. So, engine life of 30+ years (roughly half the design hours) is common, hence the number of boats of this age that are re-engined.

On the other hand if the boat is used intensively, either for long term passage making as some liveaboards do, or for charter use then the life expectancy is quite different. My Volvo 2030 did over 3000 hours in 7 years chartering and runs as well now as when it was new and has given no problems. I have seen small Yanmars with 14000 hours running that have never had any serious work done on them.

This is no different from cars. quite normal for airport taxis to clock up 250000+ miles, running at 70 mph for hours at a time but cars doing 5000 miles a year in short journeys being ready for the scrap heap in 10 years.

 

[vyv_cox]

I have seen small Yanmars with 14000 hours running that have never had any serious work done on them.

Yes. When my son worked for Sunsail he knew several flotilla lead boats using Yanmar and Volvo engines that had accumulated 15,000 hours.

 

[PCUK]

So my new Vetus engine still sitting on it's pallet will definitely see me out!

 

[sailorman]

Yes, just leave it where it is :encouragement:
GRP boats only get osmosis if you put them in water

 

[jerrytug]

Don't worry, that assertion by KE has been repeated many times and rejected by the majority of forumites on every occasion.

Richard

Well that's interesting because I have a 1972 Volvo MD3B which starts on the button, and no plans to replace my proper marine engine with a little whirring bit of Jap-cr*p.

 

[KellysEye]

>Well that's interesting because I have a 1972 Volvo MD3B which starts on the button, and no plans to replace my proper marine engine with a little whirring bit of Jap-cr*p.

I did point out that the the Volvo MD series had no design life, but RichardS forgot to mention that, it will keep running forever given regular servicing and new pistons and rings when the oil useage is high. We had an MD 17C.

For RichardS I'm not aware of anybody but you saying the design life for modern engines is 8,000 hours is wrong. 8,000 hours was told to me by Volvo when I asked about new and old engines design life span. They also said that to build a new engine to the quality of the MD17 series would cost £15,000 which means they would sell no engines because all others yacht engine brands are cheaper because they all have a design life.

1,500 rpm generators have the same life of 8,000 hours 3,000 rpm generators have a life 500 to 600 told to me by a generators sales and repair company. Their workshop was littered with beyond repair 3,000 rpm generators used for spares.

 

[dom]

1,500 rpm generators have the same life of 8,000 hours 3,000 rpm generators have a life 500 to 600 told to me by a generators sales and repair company. Their workshop was littered with beyond repair 3,000 rpm generators used for spares.

Good to know; I'll order two next time around!! At 20 days continuous running can you imagine the pallet loads of new generators industrial companies must have lying around their yards?

 

[RichardS]

For RichardS I'm not aware of anybody but you saying the design life for modern engines is 8,000 hours is wrong. 8,000 hours was told to me by Volvo when I asked about new and old engines design life span.

I don't actually know whether that is what Volvo said or not but either way I just don't see the relevance as these engines will generally go one forever if they are maintained correctly because they are subject to very little stress. As others have said, what normally kills them is saltwater corrosion which, I assume, is not something that Volvo have designed in.

Richard

 

[pvb]

The whole argument about "design life" is basically irrelevant, because 99% of boat engines don't get much use, and the spare parts availability will dry up before the engines reach anywhere near 8000 hours (or whatever the current claim might be).

 

[CAPTAIN FANTASTIC]

My Volvo MD11C is 40 plus years old and is going strong. My previous car Mercedes E300 diesel had done 324,000 miles when I sold it; my current Mercedes E220 has done 250,000 and it run very well. Changing oil regularly is important, and in my case I always use the latest oil technology for all my engines, regardless of age, which is synthetic oil.

 

[pvb]

....I always use the latest oil technology for all my engines, regardless of age, which is synthetic oil.

My thoughts too, although many people here will tell you that synthetic oil will ruin an old engine!

 

[Kelpie]

My thoughts too, although many people here will tell you that synthetic oil will ruin an old engine!

There are some very persuasive explanations of how engine oil plays a function in regulating the pH of the engine, and that this environment is very different depending on the age of the technology. But if it works...

 

[Tranona]

>Well that's interesting because I have a 1972 Volvo MD3B which starts on the button, and no plans to replace my proper marine engine with a little whirring bit of Jap-cr*p.

I did point out that the the Volvo MD series had no design life, but RichardS forgot to mention that, it will keep running forever given regular servicing and new pistons and rings when the oil useage is high. We had an MD 17C.

For RichardS I'm not aware of anybody but you saying the design life for modern engines is 8,000 hours is wrong. 8,000 hours was told to me by Volvo when I asked about new and old engines design life span. They also said that to build a new engine to the quality of the MD17 series would cost £15,000 which means they would sell no engines because all others yacht engine brands are cheaper because they all have a design life.

1,500 rpm generators have the same life of 8,000 hours 3,000 rpm generators have a life 500 to 600 told to me by a generators sales and repair company. Their workshop was littered with beyond repair 3,000 rpm generators used for spares.

So, the basis for your statement is what you were told by Volvo. Hardly an independent source - and he would say that would he not? as the later engines sold as Volvo are not actually made by them.

The reality is that the oily bits of the latest engines will last just as long as the older designs, but die possibly quicker in marine use even quicker because they are saltwater cooled and suffer from neglect. Add to that the cost and lack of supply of spares now makes them uneconomic to repair.

There is a sound reason why Volvo stopped making old style engines. The competition mainly Yanmar brought superior products to the market. Old style heavy engines might have been suited to old style heavy boats, but not to the newer designs that came along in the early 1980's. Volvo's first attempt at building modern engines itself was not hugely successful and they only got their market share back when they adopted Japanese made Perkins engines as their base.

 

[Tranona]

My thoughts too, although many people here will tell you that synthetic oil will ruin an old engine!

Doesn't ruin engines, just not necessary for the type of engines we use in small yachts.