Mercedes diesels

[Crimea Cruiser]

They were installed in many boats from the 1960's to 80's on the premise that they had long track histories of dependability as taxis throughout the world. With parts and factory hubs not only in Germany but Venezuela and elsewhere. Several European car manufacturers made the crossover into marine diesel engines including BMW, Volvo and MAN.

[SkiprJohn]

Originally Posted by deckofficer

If I remember right, my ThermoKing reefer used a de-rated 190D (de-rated from automotive use of around 70 hp or so, to 36 hp) and I know I sold it with over 10,000 trouble free hours on the Hobbs.

Got the ThermoKing Overhaul Manual right here for the OM636 which was in the 180d. It is a governed engine and did not control speed by air intake such as the car did. It also did not have a variable speed fuel injection pump so it would not tweak the injection pump as the engine came up to higher rpm. Otherwise is identical except that it had no belt drive on the front of the engine. I had to drill and tap the end to accept pulley for belt drive to get the intake pump working.

[Astrid]

I've been using a marinized 190D W201 which has worked extremely well for me.

[Cherp]

Thanks for the replies. It looks like the old Mercedes 120s were used in all sorts of applications through the 1950s to the 1980s, in all sorts of applications all over the world. I think they are probably a very reliable old plugger which deliver high hours if they are treated properly. So the maintenance record is the key issue.

[SkiprJohn]

It's likely that if you saw a 180d at the side of the road needing assistance it will have gone at least 500,000 miles and may need a fuel filter change.
Since they have that really rounded fender pontoon look you might not even recognize it as a Mercedes. Dang good old cars. Not very fast though.
kind regards,

[bstreep]

I would kill to have a MB diesel in our boat, instead of a stupid Yanmar. MB knows how to build an engine that's easy to work on. Yanmar builds "pretty engines" that are packaged well, but takes 3 tiny hands to work on. I've worked on many, many MB engines. Easy maintenance is a BIG issue with their design engineers.

[Cheechako]

yeah, I bought some spares for my 240 based Nanni at the Mercedes Dealer in Annapolis (1998). The Fresh water pump was $35! that's right $35 not $350!

[GTom]

I may be in the market for an OM 636, what I read in this thread is reassuring. One little concern though: how is the fuel consumption of this venerable piece if fitted on a 7tons Westerly?

Apparently parts are still available in contrast to decade younger Volvos.

[Jim Cate]

Originally Posted by GTom

I may be in the market for an OM 636, what I read in this thread is reassuring. One little concern though: how is the fuel consumption of this venerable piece if fitted on a 7tons Westerly?

Apparently parts are still available in contrast to decade younger Volvos.

No specific data, GTm, but to a reasonable approximation all normally aspirated mechanically injected diesels of recent (loosely defined) vintage give similar fuel consumption in terms of grams of fuel per hp hour. So, I'd not worry much about that factor in your thinking.

Jim

And yes, that Merc falls into my "recent" category!

[Diesel Bill]

I bought a 96 MB 300 D a few months ago from a friend of a friend. I'm using it to go from home to the boat and back. A 180 mile round trip. The car has 145,000 miles on the odometer. I top off the fuel tank and zero the trip meter and fill up when I return home.
L.A. driving is done at either walking speed or 80+ MPH. Normally I go very early so it's usually high speed driving. I crunched the numbers yesterday after the fill up and came out to 29.19 MPG. It has the non turbo 6 cyl. all aluminum engine. Chain driven double overhead cams and 4 valves per cyl. for all you gear heads out there. yet only produces 137 H.P. Very low stressed engine. The car is rated to go 32 MPG at slower cruising speeds (65 - 70 MPH ) I did the oil and filter change and a new serpentine belt. Got a couple of new fuel filters for spares. I'm really impressed with the drive train. Over all I think I got a winner.

[Dockhead]

Originally Posted by Jim Cate

No specific data, GTm, but to a reasonable approximation all normally aspirated mechanically injected diesels of recent (loosely defined) vintage give similar fuel consumption in terms of grams of fuel per hp hour. So, I'd not worry much about that factor in your thinking.
. . .

Yeah, that's right, as long as it's not greatly oversized for the load, the fuel consumption will all be about the same between different diesels. So very different from spark-ignition (gas/petrol) engines.

Turbo and/or common rail may improve efficiency somewhat, but turbo will only be more efficient in the load ranges where boost is being produced.

Pay attention to the prop, however, which has a lot of influence on speed and fuel consumption.

I like these old diesels, myself. The marinization parts will disintegrate before you ever need to do anything major to the engine itself, in most cases, so long as you don't overheat them or run them without oil.

We had a Perkins 4-108 on the last boat which must have had over 20,000 hours on it by the time we sold the boat. Never even had the head off it.

[delmarrey]

GTo,
Before you purchase check on marine parts for that motor, like water cooled exhaust and exhaust elbow. The VW/Pathfinder 1500 went obsolete because the exhaust and water pumps were no longer available. I ended up retrofitting both water pumps to keep mine going for a couple more years.

[a64pilot]

If you look at the Brake specific fuel consumption numbers for Diesels, you’ll find that even common rail and turbo doesn’t make much difference.
Common rail has huge noise vibration and harshness advantages, can greatly increase HP per cu in and of course easier to pass emissions, but doesn’t do much for efficiency.
The same for a turbo, it’s mostly a power adder.
The way both common rail and turbos increase efficiency is by allowing a smaller, lighter motor to produce the same power, but if you ignore engine weight and size and just look at fuel burned to HP made, there just isn’t much difference and in fact the old low RPM motors do pretty good.

The day that one brand or type of Diesel engine is significantly more efficient than all the others, there will be a huge marketing push, you will hear about it, everyone will.

[Irish rambler]

For you folks who are afficionado's of the Mercedes OM 636 I can from experience tell that properly maintained you may never have to buy another engine in your lifetime. I had a Merc 190D saloon and later a 30' motor cruiser, both used the OM 636. Brilliant engine. OM stands for oil motor, meaning diesel as opposed to petrol/gasoline.
For the best fuel consumption (which is minimal) do make sure boat is propped correctly for when its fully loaded.
Although they're no longer built you can still easily buy spares or reconditioned engines from this company, Westfield in Lancaster, England their email address is sales@west-4x4.demon.co.uk they just love the OM 636.
For any marinisation spares you may need for the OM 636 email info@ejbowman.co.uk I know these companies are in the UK but they will ship anywhere in the world.
For cheap shipping worldwide use an Irish company called sales@sendmybag.com its not an overnight service but they have contracts with TNT, DPD and FedEx so you still get the great service, but cheaper.

If you're thinking of going into European canals (yes there are standing mast routes) in the large canals the draft is 3 metres then read my book 'Windmills and Wine', if your thinking of touring the West coast of Ireland/ Southern England then my book 'Encore' will help you. Both available from Amazon, just type in the name of the book by author, Geoff Woolley. a 5* review would be most welcome.
You can also read these threads as 'Ireland to the Mediterranean Part 1' or 'Windmills and Wine' on our sister magazine Trawler Forum.
Fair winds and safe harbours.

[a64pilot]

I think maybe we are mixing engines here, the 636 is a very old single overhead cam, direct injection design where the cam is gear driven, whereas the 606 is the twin overhead cam engine and indirect injection I believe and a much later design, the later design 606 is derived from a gasoline engine, I think.
However there are many, many variations of the venerable inline 6 cyl from MB.
The inline 6 is in my opinion the best design for our uses as it’s inherently nearly perfectly balanced.
However automotive wise, my belief is it’s the 4 cyl and that odd 5 cyl that gave Mercedes the the reputation of being low power, but will last nearly forever.