My youngest son Adam, who just turned 15, is the family’s technology junkie. He reads Wired and Make, has a loaded iPod Touch, texts 4,000 messages a month and wants to be an aeronautical engineer. But like so many kids these days, he’s been able to satisfy his curiosities and scratch his experimental itches almost entirely in virtual reality, using electronic devices, the Web and some incredibly realistic video games.
So he surprised me the other day by asking if he could take apart an engine over the summer. “Just maybe an old lawnmower engine,” he said, “Something that I couldn’t mess up.”
I suggested that it would be much more satisfying if the engine ran when he was done. “The rings never seated right after the last rebuild on my motorcycle,” I told him. It’s a BMW R75/5, an air-cooled horizontally-opposed twin with pushrods, simpler in many ways than a lawn mower. “You can take it apart so we can deglaze the cylinders. I’ll help you do it right.”[pullquote]
Before we could take that machine out of service, we needed to get another one running that had been sitting for four years. This Honda CBR1000F has a water-cooled inline four with double overhead cams and screw-type valve clearance adjusters. It needed some carburetor work and before re-synchronizing the carburetors, it’s wise to check the valves. Lots of parts are packed tightly together on this machine, and the valve adjusters, especially on the exhaust valves, are hard to reach through a maze of hoses, parts and cables. I asked Adam if he would observe and assist.
To get started, I showed him the shop manual with the diagram of the cam, follower and adjuster so he could understand what we were doing. We took off the valve cover and positioned the crankshaft properly, then I had him place and pull the feeler gauge to check the clearances before and after I made the adjustments. We were enjoying our good fortune that only the intakes required adjustment until we got to cylinder number 3, which had a slightly loose exhaust valve. “Drat,” I said, or words to that effect. “This exhaust’s a little loose. We’ll have to adjust it.”
As I began to fumble through my collection of bent wrenches and ground-down screwdrivers to find a combination that would let us move the hidden adjuster, Adam said, “But Dad, that feeler gauge is an 0.008. The specification says 0.007 to 0.009 — if a 0.009 won’t go in, it would be OK, right?”
Now when it comes to using feeler gauges, my habits were formed long ago as a professional mechanic: I set valves exactly to the center of the specification. I’m not happy unless I feel that perfect amount of drag that says both sides of the gauge are in contact, and the valve is still definitely closed.
But my experience was mostly gained on engines where all the valves generally needed adjustment, and precise adjustments were easy to make. The valves on newer engines are harder to get to, hold their adjustments longer (sometimes indefinitely) and often are adjusted with shims at 0.001-in. increments — you can’t get them perfect.
On reflection, I knew Adam was right. The 0.009 gauge wouldn’t go in, so we saved our knuckles and called it good.
At Plant Services, we write a lot about the skilled labor crisis. The aging Baby Boomer generation of experienced workers is retiring and taking its knowledge with it, which threatens the future of many enterprises. This came up during the research for next month’s cover story on wireless technology for condition monitoring. I’ve interviewed several experts who have mentioned not only that the new technology will make it possible for less skilled workers to get more done, but also that the retirement of the aging workforce is reducing resistance to the new technology.
Young people don’t have our knowledge, training or experience, but they also aren’t burdened by our habits and traditional mindsets.
For Father’s Day, maybe Adam will get me an iPod.
E-mail Paul Studebaker, CMRP, editor in chief, at [email protected].