MD3 Volvo

[nzmal]

My Cavalier 39 has a tired old md3 Volvo... So I'm looking at a re-power.
I've found a new md3 that is in the crate from the factory and never been installed...
So now I'm tempted to swap it for the old as a simple exchange... Provided I can buy it for about US$4k...

Am I better off just going to a new modern and spending the time refitting mountings etc... Or is there merit in retaining the old (new) Volvo. obviously there is no warranty on the new md3...


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[gjordan]

It is just my opinion, but buying a direct bolt in replacement is the very best way to go. You might ask the seller to allow a mechanic to do a bore scope and take off a valve cover to check for corrosion,of course at your expense. There may be some seals that have dried out over the years, but even if you had to do some maintenance it would still be an easy replacement. I assume you meant MD3B, not the very early MD3. Sticking with the Volvo would also keep the option of hand cranking, which is almost never available with more modern engines. Install fresh water cooling and the engine will probably outlast you and another generation. Price a modern 36 HP motor and all the changes required and it will look even better. Keep the old engine for parts. Again, just my 2 cents worth. ____Grant.

[nzmal]

Thanks Grant
That's exactly my thinking... yes mď3b.

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[roverhi]

Loved my MD2b. Hand crank started it for most of the 10 years we owned the boat. Did start an MD3b with the crank but it was not nearly as easy as doing it with only two cylinders. Wish they still made them. Will save a ton of money changing type of engine because of all the small and large things you'll have to change. Even if you do most of the work yourself, going with a different type of engine will be way more expensive than putting in another MD3b.

FWIW, still have the Volvo hand crank laying around if anyone wants it.

[nzmal]

Thanks Peter
I'm considering making a crank handle.. Hawaii isn't on my sailing route for a while. The boat is new to me so I'm very much in learning mode. There's and old md3b on the local auction site... Very tempted to buy it and pull it down to see how it all works😊


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[gjordan]

No matter what your sailing/cruising plans are a good selection of spare parts properly stored onboard can save you much time, money and grief. A new starter for most mid size diesels can run $500 or more, water pump can be near that and on and on. Taking the parts off of the old Volvo and getting them checked/rebuilt and put in sealed containers can save your bacon (and pocket book). If your present engine or the new/old engine you are looking at, or the auction engine has fresh water cooling ,I (my opinion) would jump on it. Make sure you have clean fuel, good water circulation and a very well designed exhaust system and most diesels will last a lifetime. Best of luck. _____Grant.

[roverhi]

I wouldn't be put off by salt water cooling on the Volvo MD series of engines. They were designed for salt water cooling and didn't seem to have problems in reliability or service life. The MD2 in our old boat went on for more than 20 years, maybe 30 and 3 trips to SoPac before the then owner replaced it. Don't know what finally went wrong with it but suspect it was wanting more hp had a big factor in the decision to replace rather than rebuild.

It is probably not a factor in choosing an MD series engine now because of parts availability and cost, but every part that might suffer from cooling water corrosion was replaceable. Further, you could totally rebuild the engines, with maybe the exception of the main bearings, with the engine in the boat. Rod bearings, cylinders, heads etc were all removable without having to pull the engine. I managed to hydrolock my engine when new that shortened a connecting rod. The mech. pulled the offending cylinder's head, cylinder, piston, changed out the rod and put in new bearings with the boat in it's slip.