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  Topic Review (Newest First)
12-09-2005 05:03 PM
DIY diesel overhaul

Four years ago, I had the misfortune of having the engine block on my Volvo MD2B rust thru. I was forced into a rebuild and like you I had mechanical ability, however I had never worked on a diesal engine before. Luckily I happen to enroll in a 30 hr. diesal maintenance course at our local Marine college. We had to rebuild an engine which was provided by the school. I was allowed to use my engine instead. At the end of the course, I had a new engine which was working great. What I have learned from this experience was that it is not difficult, and not that much different from rebuilding motorcycle engines. The main thing is to be organized, keep things clean and labelled inside ziplock bags, take your time and get a manufacturer''s shop manual. It is well worth it.
12-02-2005 09:28 PM
DIY diesel overhaul

I work on marine diesels for a living, however, I have only a very limited experience with Westerbekes'' so I am not that familiar with them. From what I have seen they seem like a simple, straight forward diesel. There are a number of questions that come to mind. I know getting straight, concrete answers from people is difficult, but ask the person you bought the boat from if they know when it was run last and what were the events surrounding it "locking up?" Are there any service records? Did anyone work on it just prior to it locking up? Exactly how old is the engine? Have you ruled out that the gearbox, shafting and prop are not keeping it from turning over? I''m assuming you checked out the electrical (all connections clean and tight, load test batteries, remove starter and hook a battery up to it to make sure it works, soleniods operable, etc.). If and when you do get the engine cranking over, make sure fuel comes out of the pressure side of the pump. Look at the oil and antifreeze quality. Remove the glow plugs or fuel injectors and make sure there is no water on top of the pistons. Disassemble and remove the exhaust piping, risers and exhaust manifold. What you are looking for is evidence of seawater (or antifreeze, oil, etc.) in the cylinder area. If you have a water lift system, make sure the muffler is drained of sea water. Keep track of how much water drains out, its'' quality and color. If water has entered the engine through the exhaust manifold, then it could hydraulically lock the engine, keeping it from rotating. This is especially important to look at if the engine''s exhaust manifold is below or near the water line of the boat, like in a sailboat. If there is a siphon break in the sea water system, be sure to inspect the valve and make sure it not clogged. Make sure the seawater circuit''s dimensions and design are with in acceptable standards. You want to rule out that this system is not at fault. I attended a workshop put on by a marine diesel mechanic of 35 years who stated that 90% of engine failure is due to sea water getting into the engine from failed exhaust elbows in the risers or other failed components in the sea water exhaust circuit.

If you have gotten this far and nothing definite arises, then I would recommend you be prepared to hire a professional marine diesel mechanic. The next step is to remove the engine head (remove the fuel injectors so you don''t damage the tips). This is something you could do, but it takes someone with experience to examine the tops of the pistons and valves to understand what may have taken place. If you do this yourself, then do not disturb any debre, carbon, rust, liquids, etc. Treat the engine like the scene of a crime. The mechanic, should you hire one, will want to see this area undisturbed. I would also have the oil pan removed (if this is possible without removing the engine) so the mechanic can remove a piston or connecting rod assembly for inspection. Be sure to save the drained oil and any debre that comes out with it, especially metal pieces. Connecting rods have been known to bend when the cylinders fill with water or any liquid and the engine is ran. If the cylinders are full of some liquid, then the engine won''t bar over.

Overhauling a diesel engine isn''t that hard. Anyone can tighten and loosen bolts. But generally, I would discourage folks from doing their own overhauls. The big problem is that inexperienced people just do not know when they are looking at a potential problem, nor do they know how to reassemble it properly. There is a lot of bad advice from shade tree mechanics out there. Over the years I have listened to non mechanics talk about doing their own repairs, some with success, others with big bills because they wound up having to hire a mechanic to come in and clean up the mess they made. I admire the DIY, and I would encourage you to learn as much as you can, but do hire someone, at least to look over your shoulder. The last thing you want is to be out on your boat and have an engine failure, putting yourself, your family, the boat and others in possible danger. I''m not trying to scare you, but I''m just being realistic, because if your not, the currents and weather will be.

Be sure to get several opinions from reputable marine mechanics who understand boats and your particular engine. Don''t hire some hillbilly redneck guy who has never been to a marina. Verify the troubleshooting they do - this is very important, I can''t emphasize this enough. I''ll give you an example. Last week at work I was instructed by my boss to replace a 250 lb. Kohler generator because it "locked up." This was the diagnosis of another mechanic who said "the engine won''t bar over." Getting a generator in and out of the boat was more than an afternoon project. I always troubleshoot the problem myself first, I don''t care if Mr. Goodwrench, Bob Villa and some NASCAR mechanic have diagnosed the problem already. When I questioned my boss, he inturn found out that this other mechanic did not even know what "baring an engine over" meant. In fact, the other mechanic did not even go down into the space to even put a wrench on the generator. After troubleshooting the problem myself first, it turns out the battery was dead. Put in a new battery and the $5,000.00 generator was up and running. This kind of thing happens all the time.

Anyway, good luck with your engine. Keep in touch, let me know what you find out, I''m curious to hear about this.
Vince Hosea
08-08-2005 06:34 PM
DIY diesel overhaul

I just bought an old boat. the westerbeke W21a diesel engine is locked up and won''t turn by hand. The mechanic said i need a new engine without even looking it over.

I don''t know much about diesels but i''m good with all things mechanical and not afraid to take on something new if i have a god book or to to follow.

Is overhauling a diesel really all that difficult for a novice? I have a pretty extensive set of tools and i''m willing to buy the rest (i think).

Are there some things i can try that might free up the engine?

All thoughts and comments would be appreciated.


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