2009 Week 17 in Review
April 19 to April 25, 2009
OTM Inc in Illinois
I spent most of this week in the middle of an Illinois corn field, but it sure felt like the bilge. The worksite is called "the bottoms," a huge area about ten feet below the Mississippi River. It's part of the Indian Grave Drainage District, and is kept more-or less dry by the Indian Grave Pump House:
The pump house has three five-cylinder 32E14 stationary Fairbanks-Morse diesels that couple to a ninety degree gear to power three large pumps below. They pump water from about 100,000 acres up to the Mississippi.
Here's some background:
Back in June, the Mississippi levee broke and the lowlands were flooded, including the pump house and the three engines. The pumps are maintained and operated by a local municipality, but due to the amount of damage sustained by the levee failure, and the fact that the levee is maintained by the Army Corps of Engineers, the Corps is footing the bill to repair the pump house. The project includes replacing the windows that were blown out, repairing the pumps that were damaged, and rebuilding the engines that were flooded.
Any Corps job is swamped with requirements, assessments, a paper trail, bids, oversight, and certifications. The Corps stipulated that the project include rebuilding the engines and that the main bearings be re-babbitted. They entire project went out to bid, and a construction company called Lamar Construction got the winning bid.
They hired a great heavy equipment mechanic named Keith to work on the engines. Keith and his crew disassembled them, sent out the bearings, and ordered rebuild kits. When it came time to fit the newly re-babbitted and machined main bearings Keith called on OTM Inc to help with the job.
I arrived in St. Louis on Tuesday and drove the 100 or so miles to Quincy, Illinois. I showed up at the worksite, but immediately met with some disapproval. To some of the guys in this field, I just look too young to be the "expert" called in to do a finicky job like fitting in main bearings, so the Corps inspector lectured at me for a while about minimum experience requirements. Fortunately, I have ample experience in doing this and lots of other old-engine jobs. More importantly, I have a phone with all the old-timers and trade professionals on speed dial.
The Corps guy eventually left me alone and I began to measure things, starting with the journals and the bearings. I installed a shell as a test and found that it was really tight, so I kept taking measurements and started getting worried. None of the shells really looked right, and the fit was terrible. I started to doubt myself and I had got all these guys breathing down my neck and I was really sweating for a few hours. Then I realized that the bearings really wouldn't do because they were also non-concentric (by fourteen thousandths of an inch!) and undersized, and the problem was probably with the original machine-shop re-babbitting process.
I knew at this point that I couldn't accept this kind of work, but I felt like I needed to build a case before I could just reject the bearings. The guys at the pump house were pretty skeptical; they were like "You're here to fit the bearings; can't you just scrape them to fit?" I had to explain that the scraping is part of a process where a perfect bearing is fit to an imperfect shaft. To attempt to scrape 14 thousandths out and then make it fit is way too much to ask.
They still weren't convinced, so I measured the shells in a million spots, then installed a few to illustrate how bad the patterns were, then dug up a new bearing to show how they should be. The guys at the pump house eventually agreed with me, so I then drove to the machine shop to find out what process they used.
The bearing shells are straight with a 175 degree curve to them - like a pipe cut in half. The process that I'm familiar with for re-babbitting shell bearings goes like this:
Once the old babbitt is machined out and the steel shell is tinned, they chock it up and spin in a lathe while melted babbitt is poured into it. The centrifugal force helps ensure that the babbitt is seated well on the steel shell and any bubbles or impurities move to the inside surface of the shell. This shell is thin and warps after new babbitt is attached to it. Machinists hammer on the babbitt to relieve the tension, then fit the bearing into a saddle the same shape as the one in the engine. Then it gets squished in there really tight and machined to the diameter of the journal. This ensures concentricity.
In contrast, the machine shop selected for this job has never worked on shell bearing like these before. I don't think they really knew where to start, and it showed in the "finished" bearings. They specialized in flame-spraying or "metalizing," and they used this process to build up the babbitt, rather than pouring melted babbitt into the spinning shell, and the machining was done by holding the shell in an oversized fixture and with one bolt threaded into the back, instead of a clamp. This left the shells twisted and in some cases curled or flattened. The shells must be perfectly concentric or the shaft will be forced to one side and then the other.
Fourteen-thousands non-concentric is a lot when you're talking about bearings -- on other jobs, I've scraped and scraped for days and only taken off two or three thousands for all that work. The machine shop guys said that something like "well, fourteen thousands is the best we can do." My smart-ass reply was "look, the bearings were perfect in the 40's and we are, I'm guessing, more technologically advanced now."
I haven't encountered using the flamespray process to re-babbitt a bearing shell before; I've only used centrifugally cast in my other jobs. I'll do some homework over the next few weeks and report back about what I find.
For this job, though, the flamespray shop people were in way over their heads, since they'd never worked with these kind of bearings before. The whole situation could have been eliminated if some resourceful person had called a few people and asked a few questions, then a few more, since ultimately that leads back to Dan. I've found that the moral of any story like this is to ask yourself "What would Dan do?" and then do it.
So, at the end of the week, I sent the bearings back to be re-babbitted again and I'll be back in Illinois soon enough.
Tour of the Anheuser-Busch Busweiser Brewery
While I was in St. Louis, I took the tour of the Anheuser-Busch Budweiser brewery and got my two free beers:
The tour was pretty good, but I was really mad that they didn't talk about how the brewery used the first non-experimental diesel engine in America. It turns out that Mr. Adolphus Busch got the American rights to produce diesel engines in 1897 and retained Mr. Diesel himself as a consultant. The Busch-Sulzer Diesel Engine Company eventually produced both stationary and marine diesels, installing them in big ships, ferries, and public utility electricity plants. They also got lots of US Navy contracts during WWI and WWII.
The tour didn't go into any of this, but I guess that's fair since they were talking more about how they make beer and the brewery's history, rather than about the awesome emerging technology at the time. They did mention that they used refridgeration, which was pretty special back then.
Aside from that, I was totally impressed by the whole production and how industrial it all is. The buildings take up many many city blocks with pipes connecting them all and trucks going in and out. If I didn't know it was a brewery, I would have thought it was a refinery or something.
All that for beer.
