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Old 26-03-2015, 10:31   #16
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Re: Rebuild vs. Repower, where to draw the line?

The very BEST spare part for an engine to have on board is a competent owner. After 30 years in yacht service and building and living aboard my own boat, I have been forced by circumstance to learn many things I might have otherwise avoided. Here are a few of my recommendations:

Before you shoot the horse, at least make sure his leg is broken. My list of other possible problems and their solutions:

1. A partially clogged muffler. Any engine using 30% of it's energy trying to force water and exhaust overboard feels weak and 'black stacks' too early. Same thing with a restricted intake.

2. We are notorious for using and hoarding diesel fuel. This inevitably results in dirty injectors and injection pumps. Some Sea Foam or Mystery Oil in the fuel may soon have your engine running crisp and clean. Restriction in the fuel line can also cause problems, check that out as well. When running the engine to push fuel cleaner through the system, have it tied up properly and in gear, a little above idle speed.

3. Check your gearbox and running gear, too. Remote, but not impossible. I found one man who's cutlass bearing - rubber in bronze - had eaten it's rubber, which was now doubled over and binding severely. I also had a customer call and tell me to pull the Mercedes diesel out of his 58 foot sailboat and replace it 'because it was out of power and almost allowed him to be blown onto a stone jetty. When I checked the boat out, it turned out his high-end feathering prop and locked into the feathered position from marine growth and needed to be cleaned. A diver cured the problem in an hour.

After going through these things and satisfying yourself as to the need to pull the engine, I recommend you do so. Build a small stand for it with a set of dolly wheels, and spend some time looking it over and checking it out. Other people will be sure to join you and in short order, after talking it to death, you will know exactly what to do and should have some excellent leads to check out. In the end, you will have to navigate your own solution. On my boat, I ended up with a Pathfinder that I could not be happier with. A couple of years ago finances forced me to rebuild my own injection pump. This involves black magic and I cannot recommend it. However, there is a Buddhist Monk living in a cave on a Mountaintop in Nepal who can help you regain your sanity after doing the task six time before getting it right.

Best of luck, and fair winds.
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Old 26-03-2015, 10:32   #17
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Re: Rebuild vs. Repower, where to draw the line?

One consideration is that the newer engines are so much cleaner burning. Once warmed up, I do not smell that Diesel smell from my Tier-2 engines.
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Old 26-03-2015, 10:46   #18
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Re: Rebuild vs. Repower, where to draw the line?

Well, the boat is already out of the water and has been trucked to a location where she will sit for the next 18 or so months while all this is going on, including replacing all the rigging, repainting, redoing the galley, etc etc etc.

So unfortunately, a test under load in the water is not an option.

It seemed to do fine under load before; oil pressure was never an issue, but it would burn through half a quart every 100 hours, when I would change out as much oil as I could by pumping through the dip tube (the recommended method, actually). There would be some black smoke when it revved up initially, but nothing noticeable after that.

Again, my concern is availability and cost of spare parts. They are expensive and only available from one dealer in Sweden, and for who knows how long into the future. The engine has a great track record with other owners, but yeah, who knows about my engine specifically until I can get in there.
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Old 26-03-2015, 11:04   #19
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Re: Rebuild vs. Repower, where to draw the line?

Why do anything. You haven't identified any condition to warrant such extreme measures.


If it is hard starting or low power due to loss of compression, or vibration due to worn bearings, that's a good reason to do something drastic.


If it is that you are frightened of failure in remote locations with no access to parts, you answered your question, go with new.


If it has been a good engine and is confirmed worn out, and parts are easy enough to get, rebuild.


New Diesel


Pros: Smooth, compact, lightweight, quiet, reliable, parts everywhere.


Cons: Expensive, could be as much as engine cost again for parts and installation.


Rebuild


Pros: Fits back in without replacing everything. Lower cost.


Cons: Left with an old engine, with mostly old parts. Parts may be hard to find. May be less reliable. Most likely more noisy, smelly, heavy, rough running.


Someone in the thread was wise to mention that newer diesels don't have provision to hand crank, which is a real loss IMHO. With a hand crank, one can start despite dead battery, wiring problem, starter or solenoid problem. (A charged booster pack will solve the dead battery issue but not the others.)


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Old 26-03-2015, 11:10   #20
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Re: Rebuild vs. Repower, where to draw the line?

OK, just as I was working on my response you identified a reason for change; using oil. First step, confirm it is burning vs leaking. If burning, overhaul or repower is in order.
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Old 26-03-2015, 11:22   #21
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Re: Rebuild vs. Repower, where to draw the line?

Quote:
Originally Posted by ramblinrod View Post
OK, just as I was working on my response you identified a reason for change; using oil. First step, confirm it is burning vs leaking. If burning, overhaul or repower is in order.
OK a half a quart in 100 hours is extremely low usage for an older design Diesel, almost too low, you want to burn some oil to keep the upper cylinder lubricated. I bet it would burn at least that much if you overhauled it.
I know it's not an aircraft engine, but normal oil consumption for a 6 Cyl Aircraft engine is 1 qt per 10 hours just as an example. Older designs are designed to consume some oil

If your burning .5 qt per 100 hours and you have good oil pressure, there is no reason to rebuild anything, at least not from the oil pressure / consumption anyway.

I would tell you even if it's burning 1 qt per 10 hours, if it starts easily, makes good power and doesn't blow blue smoke after being warmed up and under a load, then everything's fine.
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Old 26-03-2015, 12:04   #22
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Re: Rebuild vs. Repower, where to draw the line?

Some engines can be rebuilt in place. They don't have to be removed from the boat. Perhaps yours is one of these. That would make rebuilding less expensive.

A different, brand new engine is enticing but it's going to be expensive to buy and expensive to install once you consider all the modifications to the boat, new instrumentation and controls.

It's fine to ask for advice but remember, you are the one who knows your boat and engine and you are the one who knows your abilities and financial situation.
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Old 26-03-2015, 17:28   #23
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Re: Rebuild vs. Repower, where to draw the line?

If you run the boat on the hard do not hook it up to a hose. Run a hose into the raw water filter with the lid off & let the motor pick up what it needs.
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Old 30-03-2015, 23:03   #24
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Re: Rebuild vs. Repower, where to draw the line?

Quote:
Originally Posted by verkerkbr View Post
If you take a new diesel engine, then you have a lot of extra costs:

Changing the engine bed
you need a new propellor shaft
probably also another propellor
changing the exhaust system
remote controls
exhaust system
replacing the instrument panel

and does it fit in the engine compartment ?

And a new modern diesel engine does no longer have a handstart.

Overhauling the old engine:

Albin is no longer in business, how about spare parts not only now but in the future ?

Is it a direct cooled engine ? Then the cooling system and the cilinder head are probably clogged.

Parts for an old engine are becoming scarse and more expensive every year.

But the engine can easily be replaced after the overhaul.

I have bought a second engine of the same type. You can use the engine parts of this engine as spare parts. I'am going to overhaul this engine and keep it, if the original one fails, I can immedialy replace it with this second engine. And I have all the parts for the engine available.

You can buy a second engine of the same type for a small sum from people who have decided tot fit a new engine.

But look for a engine with an intercooler system.

If I had to replace the engine, I certainly look for a marine engine based on a car engine. Then you have service points for your engine at almost every car dealer.

Bram
I chose the same solution for my obsolete yanmar h/e cooled (30 + years old, few parts available) I found another excellent runner for $2,500. We took it apart to check everything, putting rings in it, just because we have it open, looks like new inside, bearings, cam.... I designed the boat for an easy engine swap, so if we drop in an identical engine, we can be running again in 2 days or so. (Commercial use)
New engine prop and shaft would take 2-3 months out here, if I am lucky.

I am lucky in one respect..we found one badly corroded casting in the oil heat exchanger/ oil pressure regulator which is part of the block, we needed to reproduce the part or pull it off the other engine if we need to swap them out. I got quotes for up to $3,000 in the U.S.A. for the 25 pound casting. I had it reproduced here for around $400, with all machine work.
This old beast is pretty well known out here, easy to work on, my current example has around 34,000 hours and does not smoke. Having an exact spare is the right choice for me, especially since I can have parts made so cheap. New pistons and cylinders are not available, but they have adapted pistons and cylinders from another more current model to fit, it is a proven replacement, so I think I am good to go for the very long term. I am into it all up about $6,000, which includes the tear down, rings, the casting, fuel pump rebuild, turbo rebuild, gaskets.....Essentially a new drop in replacement.
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Old 31-03-2015, 15:10   #25
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Re: Rebuild vs. Repower, where to draw the line?

What kind of Yanmar is that? Impressive.


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Old 31-03-2015, 16:09   #26
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Re: Rebuild vs. Repower, where to draw the line?

After 4.5 years of ownership, I know what it is and all about it. A 1978 Yanmar 6dhht. 5.4 liter inline 6. indirect injected, 100X 100 mm. 105 h.p. H/E cooled turbo. Right about 20 h.p. per liter, and about 17 h.p. cylinder. 1,500 or so pounds. Max revs 2,200. Rebuild in boat ? It has six individual cylinder heads, any one of which is off and on in an hour, with a copper ring for a head gasket. Doors in the crankcase side to get at the rod caps, so I can pull a head and replace a cylinder, rod and piston as a set in about 3 hours. An industrial beauty of epic proportions.The more I learned about it, and I knew nothing when I got it, the more impressed I am. Designed with such low stress, such ease of serviceability..You could never build it now, far too inefficient power to weight and size, but I have heaps of room and can walk all the way around the thing standing up, and the weight helps ballast the boat. This thing is designed to run forever. Crankshaft weighs about 100 pounds....rod journals are about 1.75 inches in diameter, to rush out 105 H.P.! Produced for the Japanese domestic market. 3.83 Gear box weights about 450 pounds and I am putting just over 100 h.p. through it. There are photos on this page from when I was building the boat or do an image search of yanmar 6dhht. Mine and another in the Philippines are the only two examples you will find. A joy to own, really !
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