I keep responding to your threads because I like you ocean however some on here see that as being biased and steering you one way or another(not you george)
but the md7a had some parts issues, and yes they are expensive to source some parts nowadays...some cant be except from other volvos but that applies even to yanmars...
however they ae very well built, heavy reliable and old school...
the betas are kubota blocks like many many diesels these days, and have some nice maintenance features like the built in oil pump to do oil changes, easy access of things in the front of the engine and are for all intents and purposes very global and parts available.
the atomic 4 while not ideal for a trip like this can be made to run forever, and those of us who have had them and used them know its pros and cons and how easy they are to work on.
a pro for example would be getting a mechanic to work on it in the boonies compared to a GOOD diesel mechanic
any car mechanic around the world will know the distributor, ignition and carb works based on old car experience.
cons is for cruising they can be GAS GUZZLERS...compared to a 1/4 galon an hour yanmar or similar.
they are gas of course and can be perceived as more of a hazzard but more hearsay than anything...
parts are easy to come by in automotive stores like napa for stuff like distributor caps, belts, ignitions even...
in any case the md7a has some known issues which can be:
bad comp and if watercooled only has a basic lifetime when the water passages eventually get eaten up
now here is a very nice blog talking about the md7a
Cruising and racing in the Baltic: To keep or trash my Volvo Penta MD7A?
and a sailnet one too!
remember fear and hearsay are more powerful than facts, especially on the internet
so dont let anyone tell you differently jajajaja including me
again good luck in your search