Please help me figure out this MD2B

[636man]

I have the injectors out and they've been serviced. I'm trying to turn over the engine without reinstalling them but I am unable to turn the motor over. Is there something I can fill the engine with to free it up? The motor sat











underwater for 36 hours last year which resulted in me getting a really good deal on my new to me 63 Pearson Triton. I am new to sailing and am really focused on getting this dinosaur of a motor going. I have a new starter but I think there's also a hand crank I'm unable to get my hands on. Please help me get this thing to rotate.

[Roy M]

Ah yes, the MD2B, the bane of my existence. Having sat for 36 hours in seawater, a year ago, you can now, without any sense of guilt, attempt to remove its component parts and sell the individual, salvageable ones on eBay. The rest of it will fit very well into a dumpster. There is no value in trying to renovate this engine because once you have spent huge amounts of money and time trying to get parts, you will then realize that you could have purchased a lighter weight, more powerful, smoother running and far more dependable Yanmar. I know, I tried all the other steps first, what a waste of effort and resources. While you have the engine out of the compartment, take the time to fully renovate this valuable piece of real estate. Clean it, rip out all the electrical and plumbing, rebuild the engine bed logs to match the footprint of the engine mounts for your new engine, install new soundproofing, electrical and plumbing, then take delivery of your new engine. Or don't. Maybe you are lucky. You'll find unusually dependable Volvo parts in a local museum, a mechanic who loves working on rusted engines for little money and the chance to revisit old systems, and discover the joys of a two-cylinder engine from the 1960s that has a two hundred pound crankshaft and flywheel and motor mounts that will last a couple years. Oh, and the best part, the saltwater cooling system. Oh for the days.........

[DeepFrz]

LOL

Sounds cynical to me... Cynical but great advice. Ah, the bargains.

[636man]

I know right. Any clue what the best thing to use to soak the motor in?

[636man]

I do have a 10 hp outboard on the Bach that I'm satisfied wit but I've been told an outboard is not the way to go in coastal waters. If I want to see saltwater in this boat do I need to have an inboard?

[S/V_Surya]

I had a Volvo MD6B 10hp. The rings have rusted to the cylinder walls (don't ask me how I know this). You can try pouring the marvel miracle oil in the injector ports and letting sit for some time (24 hours) but probably will not work. Try to rotate engine in small increments gently. As soon as you bust it free there may be no compression. The good news you can carry it away easily by removing head and starter.

[porsche189]

I have a MD2B myself. It is in good shape and runs great, but even a good running one has issues that pop up. Oil leaks from who knows where is where I am at the present. (engine is a bit big for the space, so locating things can be an issue) The old starter generator motor, look up prices of these old parts and you may agree with the cynical good advice.

I have been a diesel mechanic mainly on trucks, and if the motor has sat underwater, time after submersion is the BIGEST factor.. 1 year later, I doubt soaking will help the bearings if water seeped in the lower end. The cylinder walls probably have a few frozen rings to the walls, when this happens it needs to be honed out, and trying to free them, well putting a light weight pb blaster, wait hours re apply , then move on to higher weight oil, but i would bet it wont reseat itself. Rings once rust sets in, they may not hold compression.

Gaskets are expensive, more than you would expect expensive... You will ask if you have marine diesel health insurance and donate an organ to cover expensive.

*All that said, if you need to pull the parts of a frozen motor... PB blaster, then heat with a torch the cylinder walls, as big as it is, i don't think you will have a lot of luck with the torch inside the engine compartment. The goal is to have the piston and the cylinder to have a drastic temp. difference. Cylinder wall expands and the piston stays cool and you get some extra clearance.

If you love the mb2b what would you want to spend on a replacement motor, then you have a full set of parts... And I can go buy a yanmar and lower my maintenance cost over the term of ownership.

[Cheechako]

The motor should have been cleaned and started immediately after being under water. At this point it's junk. Do not put more money into it.
You can fill the cylinders with anything from kerosene to wd 40, but even if you can break them free, it's most likely the rings/cylinders will be shot. Sorry.

[F51]

I got salt water inside my cylinders. I immediately pulled the injectors and motored the engine over with the starter. I left to get some more tools and two hours later the starter could not turn over the engine due to the rust. I was able to disassemble the engine and get it going again in a couple of days. If your engine sat for a year before disassembly, I'm afraid it is unrepairable.

[636man]

New update. It has only been a few months since the boat sank. Does this make a difference?

[Celestialsailor]

Originally Posted by Roy M

Ah yes, the MD2B, the bane of my existence. Having sat for 36 hours in seawater, a year ago, you can now, without any sense of guilt, attempt to remove its component parts and sell the individual, salvageable ones on eBay. The rest of it will fit very well into a dumpster. There is no value in trying to renovate this engine because once you have spent huge amounts of money and time trying to get parts, you will then realize that you could have purchased a lighter weight, more powerful, smoother running and far more dependable Yanmar. I know, I tried all the other steps first, what a waste of effort and resources. While you have the engine out of the compartment, take the time to fully renovate this valuable piece of real estate. Clean it, rip out all the electrical and plumbing, rebuild the engine bed logs to match the footprint of the engine mounts for your new engine, install new soundproofing, electrical and plumbing, then take delivery of your new engine. Or don't. Maybe you are lucky. You'll find unusually dependable Volvo parts in a local museum, a mechanic who loves working on rusted engines for little money and the chance to revisit old systems, and discover the joys of a two-cylinder engine from the 1960s that has a two hundred pound crankshaft and flywheel and motor mounts that will last a couple years. Oh, and the best part, the saltwater cooling system. Oh for the days.........

This is the best advice anyone could give. I have been down this road too many time to argue. If the engine was newer then maybe you could rebuild it cheaper than a new engine but these are heavy antiques whose parts cost a fortune if you can even find any.

Originally Posted by 636man

? The motor sat underwater for 36 hours last year which resulted in me getting a really good deal on my new to me 63 Pearson Triton. I am new to sailing and am really focused on getting this dinosaur of a motor going. I have a new starter but I think there's also a hand crank I'm unable to get my hands on. Please help me get this thing to rotate.

Underwater 36 hours, then sat a year? The rings are probably welded to the cylinder walls and corroded to the ring grooved in the piston. Not to mention what the cam lobes look like. I bought a Volvo 2003 once that had been partially immersed for a day. we removed a freeze plug, drained it and filled it with diesel for a few days. Eventually we were able to start it but I had constant problems with it afterwards.

[roverhi]

If the engine sat for a year or more without filling the cylinders with oil and new oil in the crankcase and turning it over, the rings are certainly rusted to the cylinder walls. Got water in the oil on our MD2 because of a defective anti-syphon valve. Drained the oil, refilled with oil and ran the engine for an hour or so. Drained the oil again and it ran for 20 more years. If To free it up, you'll have to pull the heads, pour penetrating oil in the cylinders and let sit for a couple of days. Get a big hammer and a block of wood that will fit in the cylinder and tap on the pistons. Be patient and keep tapping, wait a while and tap some more. If the pistons don't break loose, more boisterous tapping will be necessary. If you get too boisterous, you'll break the ring lands on the pistons and will need new piston(s) which you may need in any case. If you get to the point where you're beating on the pistons, best to pull the engine and remove the crank. The crank bearing may be seized.

Rebuilding the engine will be costly but less than buying a new engine if you do the grunt work yourself, provided the crank, rods, heads and cylinders are salvageable. If a major component is bad, best to bite the bullet and get another engine. There is more to changing engines than just buying the engine. Shaft, prop, engine beds, wiring, etc. may all need to be changed. Those modifications can easily equal the cost of the engine if a yard does the work.

Had an MD2 in my Westsail. Great engine that can be rebuilt in situ except for the main bearings. They are easily hand cranked, did it for 10 years. Really like the simplicity of the design. We owned the boat for ten years and took it to SoPac. Subsequent owners took it to SoPac twice before finally replacing the motor midway through their second cruise and some 20 years of service. The engine is overkill for power in a Triton, IMHO. A used Yanmar 2GM20 would be a good replacement engine if you can't afford a new diesel.

[636man]

Thanks Peter

[svinshallah]

Don't get too hung up about the MD2B. The MD11C is almost exactly the same engine with a number of improvements. Fits in exactly the same space with the same mountings. I've seen more of the newer engines around than the old MD2s.

[boden36]

Roy M is on the right track. Replace it with a better engine, or you will be continually throwing good money after bad, and then have to replace it eventually anyway.

Regards ,
Richard