This June is a very busy month for Old Tacoma Marine Inc. Right after last week’s great Diesel Engine Theory class, I got back on an airplane for Illinois.
Back to Quincy
I got back in to Quincy and the Indian Grave Pumphouse to pick up where I left off two weeks ago: setting up the rod bearings on engine three. As always, I spent some time at the beginning cleaning and finding a workspace in all the piles of parts and tools. Once we actually started putting pistons in, though, we got into a good rhythm. I cleaned the bearing, fit the felt and felt springs, and put it onto the journal. Then Keith and Nathan put the piston in on the piston holder tools, then bolted down the head. Then I set the piston height by stacking about ¾ of an inch of shims between the bearing halves and pistons, using a jack to push the piston into the bottom of the head while measuring its travel with a dial indicator. The Fairbanks-Morse manual calls for .125 to .188 of an inch piston-to-head clearance. Using the above method, I could easily set them all at exactly .125.
After that, I set the rod bearing clearance. I pulled out the big stack of shims and guessed at the required shim pack, then I bumped the bearings and adjusted them. The manual calls for zero clearance and good fore-and-aft motion. This is much tighter than on pressure-lubricated bearings like those on Washingtons. The bearings on these Fairbanks only receive a few drips per minute while running, so the bearing needs to be much tighter to create the hydraulic wedge action necessary for it to work.
Now, with this in mind, I did set up the bearings much tighter than the pressure-lubricated rule-of-thumb, but I was afraid to set it all the way to zero. I know that when the book states “zero clearance” they mean “zero with a good film of oil” and probably not with a heavy-duty hydraulic jack pushing up on the bearing and maybe not using a dial indicator measuring to within ten thousandths of an inch.
So, I set everything at .004 of an inch. I see this as fair and might go to .003 if I could be there for the first 100 hours of running.
Once all the rod bearings were finished, we set up the turning tool again to see how smoothly the crank turns. It turns great! Then, we started shooting soda bottles out of the injector holes.
Also, on Wednesday, I had a nice dinner with Indian Graves Drainage District Commissioner Duke and his family. Duke really likes these old engines; he’s telling the folks at Fabius River Drainage District to keep their two 32E14 (6)s. I’m going to keep badgering them as well, and I hope to get a grant to go down and refurbish them, rather than replacing them with new high-speed diesels.
I’m scheduling another trip for July 5th to finish the next two engines.
Diesel Engine Theory Session Three
On Friday night, I flew back to Seattle just in time for the third session of Diesel Engine Theory aboard the Arthur Foss. The next morning, I got up even before the chickens – which is really impressive because Saturday was the Summer Solstice, the longest day of the year.
I stopped by the shop to get it ready for the class, then got coffee, then went to the Arthur to start up the diesel stove for Chef Kim. Then, I went back to the shop just in time. Everyone but Sterling and the three TAP guys (who canceled) were there waiting. We spent the morning cleaning more parts, testing and setting the spring pressure in the injector, and lapping the intake and exhaust valves to their seats.
Just as we were getting ready to head out, 200 naked bicycle riders went screaming by the Shop down Leary. For those of you not from Seattle, the naked bicyclists are a nationally-known tradition that opens the Fremont Solstice Parade (you should Google it). Of course, Diana the museologist and class photographer was in back photographing engine parts or something at the time, so we didn’t get any OTM Inc photos of the bicyclists. Maybe next year.
Just before lunch, we took the air intake manifold to the car wash. I’ve found this is an efficient way to clean large engine parts – it gets all the big chunks of stuff out of the parts, and car washes are all set up to handle diesel gunk, anyway.
With that done, we got to the boat where Kim had the galley baking hot and French onion soup, salad, fruit, and fresh bread, all made on the Arthur‘s diesel oven waiting for us.
It was great – maybe the best lunch ever because of the bread:
We spent the rest of the afternoon cleaning the piston ring grooves and measuring them, then measuring the piston ring gap. I think that many of the students would say that measuring the ring gap was a favorite part of the class because to do so one must get completely inside the crankpit. Wow. Standing in the crankpit, leaning on the crankshaft, and reaching overhead to place a ring in the liner to check the gap is an amazing task for those who do not regularly get into engines.
Then we lowered the piston into the cylinder and set it on the crank to get it ready for installing the rings. That job will need to wait for next week, though.