2008 Week 53 in Review
December 28 to December 31, 2008
Important winter warning
Now that winter is here, Old Tacoma Marine Inc reminds you to winterize your engine room! Use anti-freeze in your cooling system, turn on a heater in the engine room, and make sure to run the engines occasionally, even if you don't leave the dock. These are very important precautions to keep your boat and its old engine safe during the winter.
Just last week, one of our favorite boats severely cracked some large castings in the Pacific Northwest's cold snap and blizzards. We are very sad to hear about the damage and feel that we need to get out the word that the brittle cast iron easily cracks if the coolant freezes. Drain and pickle if the engine will be left for long periods of time, but using antifreeze, a block heater, and occasionally running the engine is the most effective to prevent freezing and cracking.
Work continues on the Catalyst
This week, I've continued work on fitting the main bearings into the engine. During the initial fitting, I used bluing and scrapers to get them to about the right shape; now I'm using lapping compound, which is a very fine grit, to get the perfect. This shows me exactly where the bearings and the journals actually touch so that I can scrape down any places that aren't quite right.
Part of this process is using a squisher tool to hold the bearing in place while I work. This is two pieces of aluminum that push the bottom half of the bearing down into the saddle:
Once the squisher tool is installed, I put the bearing in, put the lapping compound into the bearing, crank the engine around, take the bearing out, clean off the lapping compound, and look at the pattern of scratches that lapping compound left on the babbitt. If the scratches are in just a few areas, that shows me where to start scraping to get it to the right fit so that I can test it again. If there's scratches all over the bearing, I know it's getting good contact and is ready to go.
Once I know the bearing is getting good contact with the crankshaft, I need to test how high it is - how far up it's pushing the crankshaft. If one bearing is holding the crankshaft up higher than the others, then the crankshaft will bend. This shows up when I do a strain test to determine how far apart the throws are. If the strain test shows that the bearing is too high, I roll it out, scrape it down, re-fit it with lapping compound to make sure that the contact is still good, and do the strain test again.
Continually rolling the engine over by hand to test the bearings like this is a work out. I only have three main bearings to test, but it takes a long time to get them just right. At least as I go, the bearings start to fit better and barring the engine over gets easier.
More information on the Olympic
I forgot to mention back in Week 49 that the ferry Olympic's main air compressor was surplussed and sold on eBay a few months ago. Nick just sent me an email with the link to the expired eBay listing with information about it. Since eBay eventually deletes old listings, here's a screencap rather than a link:
It'd sure be nice to get it back for the boat.
Happy New Years!
We'll be spending the night of the 31st on the Skillful to watch the fireworks on the Space Needle. I hope that everyone reading has similarly fun plans!
