Mercedes diesel 6-570 160HP

[jeemboNC]

Gentlemen - I am looking at a late '80s trawler with a single 3600 hour Mercedes diesel in it. This is an unusual powerplant to me - does anyone have any comments? Longevity? Reliability? Parts availability and cost? Overhaul costs? Repower options? I like the boat, but I feel I may be looking at some serious engine issues way too soon (though I will probably only put 100 hours a year on it).

Also, it has a hydraulic 'docking' system consisting of two pivoting props mounted under the swim platform. It appears the condition of this system is marginal. Comments on this? Thanks to all. JeemboNC

[FAST FRED]

Longevity? Reliability? Parts availability and cost? Overhaul costs? Repower options?

Dont worry be happy.

Get a MB handbook and do ALL the maint the engine requires.

IF it was properly maintained , parts etc wont be much of a problem , at 100 hours a year..

You may need to protect "pickle" the engine during times (months) of non use.

Technique should be in "Da Book".

FF

[jeemboNC]

thanks. my problem is that I do not know if the previous owners did what you rightfully suggest. No amount of inspection will truly reveal it's internal condition. JeemboNC

[FAST FRED]

No amount of inspection will truly reveal it's internal condition. True enough , but a simple compression test will give a BIG amount of confidence .An oil sample kit is $16.00 or so, and will show a Major problem.

While there out have the injectors tested .

Then all you need to do is clean the fuel and keep it that way.

FF

[kapnD]

In my experience, compression tests are rarely done on diesel motors. They run extremely high compression ratios, and cold cranking does not duplicate actual (running) compression conditions. The simplest and most effective way to test it is to loosen the lines that feed the injectors one at a time with the engine running. The engine should run slower and louder, and the effect should be similar on all cylinders. Its similar to pulling the plug wires off a gas motor to be sure that each cylinder is firing. If you pull the injectors and find them to be dirty or plugged up, it's and indication of a problem somewhere else - in the fuel, air, cooling, lube, or exhaust system. Simply cleaning injectors will not fix the problem. You are correct that this is an "unusual" power system, and would do well to wonder why it is not more common... Perhaps you'd find some interesting reading on boatdiesel.com Good luck, Don

[jeemboNC]

Don - I have never heard of the 'loosen the lines that feed the injectors' method of assessing an diesel's health. It may be common among knowledgable mechanics, but as I said I am somewhat ignorant of diesels. Can you expand a little for me? I am intrigued how this is done, what you look for, and the science behind it. Thanks for your input - I am really learning from this forum. JeemboNC

[kapnD]

Jeembonc, As I mentioned before, have a look at boatdiesel.com. There is a wealth of free information to be had there, and for $25 you can access the archives and have the use of some really interesting software, classified ads
Can you give more details of the boat and motor? size, make/model, engine #, hp, prop size etc?
Is the engine a MTU? I'm not knocking it if it is, but unless you have an authorized service facility nearby, and can afford to use their services, this is probably not the best diesel to cut your teeth on...

[jeemboNC]

KapnD - I'll do that. The engine is in a tired Heritage East 40 Sundeck, but it was sold and a dead issue for me now. It was a Mercedes 6-570 of 160 HP with a reported 3600 hrs. Most of the trawlers I now see are powered with 120 or 135 hp Ford Lehmans, which are bulletproof and common. Some Perkins. I have been participating in the Passagemaker forum, but they just changed everything and all the history is gone - what a shame. Site's hard to use now, too. JeemboNC