‘Old Blue’ Motor Rebuild


Atomic 4 Ready for Removal Sure you really want to do this?

I installed the ‘Rebuilt’ Atomic 4 motor in 2005 and although it generally ran well, it burned about 1 quart of oil every three hours, right out the tailpipe (note: motor was NOT from Moyer Marine, who’ve been nothing but great to me).  This is pretty extreme, and meant that every three to five hours I had to stop the boat and add another quart, or more. Not only was it inconvenient, annoying, polluting and expensive, but I felt strongly I should fix it before setting off on an open-ended cruise far away from ready access to parts and facilities. So it was that with a month and a half before our looming departure date to Polynesia I tore into it, swearing that if I didn’t get it done in time we’d leave without it. After all, I could always fill the extra space down there with whiskey and wine.

Ultimately I did get it done in time. The job took ~4 weeks, though I simultaneously worked on 99 other projects in the hectic scramble that is every pre-departure, all the while doing gymnastics over the engine block in the middle of my kitchen.

After a valve-job, cylinder-honing and new set of rings, the motor purrs. No, I’ve never rebuilt a motor before, but I read the books reeeeeel careful-like.  Motors are fascinating and for all their complexity are simple, in a sense, kind of like that board game, Othello, “Minute to learn, lifetime to master.”  True, in this case it takes more than a minute (more like days), but if you don’t try, you’ll never learn.

Update 7/2012 :(  I found and fixed an electrical problem which had caused sporadic shut-downs, but high exhaust back pressure from the high wet exhaust rise seems to be causing excess gum build-up on the valves and they’re sticking sometimes, rendering the motor non-operative.  Stick it on the projects list, I’ll have to be reworking the exhaust system some time soonish, and hopefully will not have to remove the head again.  With some luck maybe carb cleaner will be a save-all and free those valves so I can start the motor once we’re back in the water.  But hey, on the bright side, oil consumption is still great.  Especially when under sail.

Here’s the gallery:

Leave a Comment