Whats so hard about rebuilding a marine deisel?

starboardyacht · #1 (**permalink**) 12-03-2007

OK folks, i've been looking at project boats in the 40 to 51 range for a while and most have engine problems, for the most part water got in while sitting neglected.

My question is whats so hard about pulling the thing out, taking it to a machine shop or a non-marine deisel guy, then stick it back in, hook it up and sail/motor happily ever after? The numbers to have this done are just crazy, are marine deisels that much different than our farm tractor? Anyone out there ever done this?

Idiens · #2 (**permalink**) 12-03-2007

It's being done all the time, trouble often is that marine diesels get so old that spare parts become a problem. But if you can also make spare parts.....

USCGRET1990 · #3 (**permalink**) 12-03-2007

If it is raw water cooled, it's not worth rebuilding, as the inside water passages are ate up. A friend in NC tried to find someone to rebuild his old Atomic-4 (gas) and no one local could or wanted to do it. As mentioned, if the engine is quite old, the cost to rebuild can be as costly as a new one.
When I say rebuild, I mean rebuild/renew every moving part. (The only way to be reliable.) Rebuilding would only be cost affective for an old retired gearhead (as myself) in that I could do most of the work..

sailingdog · #4 (**permalink**) 12-03-2007

The main differences are in the cooling system and exhaust. The block and head are pretty much the same.

j34035 · #5 (**permalink**) 12-03-2007

I've done it. Pulling a small diesel out of a sailboat is not that hard, if your rig is standing and you have good halyards. I used the main halyard to connect to the lifting sling and winched the engine (3 cylinder Volvo) up and out. Be sure and use a halyard that is rated for that heavy a load. I then swung it out of the boat and lowered it onto a furniture dolly I got at Lowes. The kind with 4 wheels. Rolled it onto a trailer and home. Back in was the reverse. Biggest issue is finding parts you need and reliable machine shops. People who do this work daily know who their best resources are, but I had trouble sorting through the different shops and suppliers to get parts and machine work done. The only really technical part I did not touch was the injection systsem, I relied on an experienced mechanic to do that for me. The rest is just pistons, rings, nuts and bolts. Be sure and get a shop manual for your engine for clearance, torque and procedures. The previous posters advice is good, make sure the finished product will be worth the labor and expense. My block, mainifolds, crank, rods, pistons, etc. were all in good shape, it only needed to have new injectors, rings and valves. Had it been much more, it would have paid to purchase a replacement engine and re-powered. Still once you are finished, you will not be afraid to tackle any issues you may run into later, because you are old friends with your engine (unless it made you and enemy!)DD

sailboy21 · #6 (**permalink**) 12-03-2007

One of the peculiarities of my engine is the oil pan. It is glued to the block, and the lower half of front and rear mains are integral to the oil pan. My cousin, a professional auto mechanic said he had never seen anything like that before. I suspect that most engine shops down the street would probably be hesitant if you mention marine. Not that there are many of those shops left. Even the big cities are down to a handful of capable shops. The people here airfreight their engines to get them rebuilt. We all view the importance of a marine diesel on a sailboat differently, but in places like i live they are a vital piece of safety equipment. You simply can't take risks here, so shipping it to the factory would be my choice. That said, a friend of mine had his Westerbeke 4cyl rebuilt by the factory. They somehow managed to LINE UP THE CYLINDER RINGS so that after a few hours holes at been burned through the liner and pistons.... So even the factory can royally screw things up.

starboardyacht · #7 (**permalink**) 12-03-2007

If it makes sence to repower, how do the old trannies hold up to all the new power? Are they spec for certain Horsepower? Do they go out faster with a new engine?

Freesail99 · #8 (**permalink**) 12-03-2007

Every quote I have ever received on a new engine included a new transmission. Some quotes gave 2 or 3 differet transmissions to choose from.

pigslo · #9 (**permalink**) 12-03-2007

The Borg Warner Velvet drive that you find in many boats is speced for more horsepower than your sailboat diesel will put out.
pigslo

xort · #10 (**permalink**) 12-03-2007

Don't stop at the engine!
If the engine is shot, what else hasn't been taken care of? Trans has been mentioned; what about the prop shaft & stuffing box, wiring, gauges, fuel system including the fuel tank full of gunk, batteries, etc.
Not to mention the rigging, chainplates, spars and all that.
Better make darn sure you know what you are getting into. Again, if the engine is shot, what else has not been taken care of.
A well maintained diesel should last a long time. If it did, then the boat is old & worn and if it didn't last a long time why not?