how long will a marine diesel last?

C

ColinR

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www.victoriashadow.co.uk
My Yanmar 2GM20 is about 20 this year and still running perfectly having been well maintained although commpression is down, about 230. The engineer says that sooner or later the raw water cooling will corrode through in the head and a new head is not really economic. So do I get out while the going is good or hang on in the hope of a few more seasons use?

Colin
 
There are plenty of ancient diesels still around, I would keep it going until it dies. My 1GM was installed in 1983, and although it is the most expensive part of the boat to run and maintain, the engine itself is still going strong. (The fuel pipes and other infrastructure are another matter.... /forums/images/graemlins/confused.gif )
 
I know somebody that had to re-engine for this very reason. His 2gm was working fine one week and scrap the next due to a corroded water jacket. The engineers told him he had done well to get so many year out of it. Just over 20 I believe!
 
Mine is also 20 this year and altho still running well I have decided to replace it with a ?3YM20 next spring. They are slightly more powerful and quieter apparently. It is nearly a straight swap altho the front feet are moved fwd. Mind you I hope they're not taller.
 
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My Yanmar 2GM20 is about 20 this year and still running perfectly having been well maintained although commpression is down, about 230. The engineer says that sooner or later the raw water cooling will corrode through in the head and a new head is not really economic. So do I get out while the going is good or hang on in the hope of a few more seasons use?

Colin

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It seems to me that it depends upon whether you are confident in your ability to cope with engine failure when out on the water in your typical cruising grounds and secondly how long you intend to keep the boat. If you are bothered by the prospect of such failure [as you say, normally due to corrosion] and expect to keep your boat at least 5 years then a new engine makes sense. Otherwise stay with the present engine until it fails as long as it starts easily. I have a VP 2002 which is 21 years old, starts very well and uses no oil. I know that it will corrode through one day but I'm planning to "stay with it" for now.
 
Just replaced my 2003T at 21 yrs - seized turbo, many oil leaks, corroded saildrive. The engine was rebuilt in 2003/4 and I wasn't going to do that again if it only extends life by a few years! New one starts instantly, quieter, no smoke, better economy (but expensive!)
 
thats my dilemma. If I was cruising locally I'd just keep it going knowing that one day it will fail and at worst I can sail back to my home port and I will have to get a new engine. But I'm planning a longer cruise next year, several months and maybe to the Azores. It would be a complete pain to have it conk out in the middle of that. So I suppose I am aswering my own question. Thanks for the feedback everyone, its helpful to air these things especially when you are trying to phych up up to spending a load of money.
 
Sooner or later could be any time in the next 20 years. My Volvo MD2B is 36 years old and still going fine. although I am beginning to get concerned about external corrosion in places that are virtually impossible to reach without craning the engine out.

Unless you have any reason to expect it to fail this year, rather than in 10 years time, then why spend the money now?

If you are worried about it then whipping the head off should give some idea about whether corrosion is a problem at the moment.

BTW while a new head might not be economic, it should be possible to pick up a second hand one for a few pounds, and fitting it is likely to be a pretty simple job.
 
I'm in a similar quandry, ColinR. My Perkins 4107 is 1969 vintage, and may not have been new then! It was installed by a German, and has run efficiently ever since. Starts on the button, despite looking like a lump of old rust.

A new engine, plus ancilliaries, will set me back around £10k - maybe more. I'm being advised to go that route, as the new engine will be more fuel efficient, quieter, lighter and more powerful for the same footprint. Spares may soon start to become a problem for Mr Perkins, and just stripping it down for an examination could still set me back £2k - so why not put that towards a new motor?

I wish the thing would spectacularly - and terminally - self destruct whilst safely moored. Then the decision is largely made for you.

I'll keep it going till then - and it gets a paint job, not exploratory surgery!
 
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My Yanmar 2GM20 is about 20 this year

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It should be nicely run-in in a couple of years time. /forums/images/graemlins/smile.gif

John
 
I quite agree - I would certainly like the excuse to fit a new engine. It would be smoother, quieter, smaller and at least 100kg lighter. What's more if we got one with indirect cooling we could fit a calorifier and have hot water as well!

Every winter I consider whether to bite the bullet and replace it but firstly I can never quite justify the cost and secondly I can't be quite sure that anything I replace it with will be as reliable. When you hear of people replacing engines that are less than 20 years old you wonder just how robust the more modern engines are
/forums/images/graemlins/smile.gif
 
' BTW while a new head might not be economic, it should be possible to pick up a second hand one for a few pounds, and fitting it is likely to be a pretty simple job.'

Where would I pick up a secondhand head for a few pounds?
 
Oooh, get a Beta, you know it makes sense.

Our Thorneycroft lump lasted 27 years (including a new gearbox and a recon job), and its Beta replacement cost £8k inc fit, but I had the *luck* to have two pressure lines give way through corrosion and that it was good enough excuse to get the job done.
 
Just to say to bedouin that you can certainly use a calorifier with a directly cooled engine. I fitted one to my raw water cooled Bukh 20 with a Bukh take off kit and Johnson pump and have had copious amounts of hot water every trip since with no problems. Needs perhaps 30-40m of engine running and the water is sufficiently hot to make it painful to leave your hand under the running tap. Probably is cooler than an indirect set up, but since these quite often have to have a mixer valve inserted because of that, I don't see it as a major problem.

By the way my engine is 25 yo & still running well to date!
 
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' BTW while a new head might not be economic, it should be possible to pick up a second hand one for a few pounds, and fitting it is likely to be a pretty simple job.'

Where would I pick up a secondhand head for a few pounds?

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As with most things these days - try ebay /forums/images/graemlins/smile.gif

With my MD2B I regularly find people selling them either whole or in parts (particularly of course in the off season when they are replacing them, nothing available at the moment) You can pick up whole engines from about £200-300. I don't see why the same won't be true for yours - it is old enough that people will be replacing them now.
 
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Needs perhaps 30-40m of engine running and the water is sufficiently hot to make it painful to leave your hand under the running tap.

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Is the 30-40m Miles or Minutes or even Metres /forums/images/graemlins/grin.gif
 
Minutes. And for a further clarification, when I refer to my engine it is in fact the boat's, tho mine is still going strong too, touch wood, tho for considerably more than 25 years. /forums/images/graemlins/grin.gif
 
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