Monday, June 29, 2009

The Crooked Foundation


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During my last years in the Navy I was involved in what was known as the Technology Transfer Program. The idea was to pass along modern technology to friendly nations; to try and bring them up to speed in using modern-day communications and computers. I often wondered why. We were fresh out of Russians, pounding their shoe on the table at the UN, shouting they would bury us. 'Rebels' were occasionally given a polite mention.

The quotes are because it was often difficult to tell who was a rebel and who was not.

The program was a marvelous success, of course. (Have you ever heard of a government program that was not?) In fact, most of the programs were dismal failures, for reasons that were painfully evident. For example, we were tasked with teaching the operation and repair of solid-state devices to electronics technicians who had never been exposed to solid-state devices. They tried -- and there were a few who did pretty well -- we'd been given the best people they had... and 'best' was determined by how well they did with tube-type equipment, the newest being Vietnam-era junk, long since replaced by more modern equipment.

A lot of the mail I get reminds me of those 'Technology Transfer' programs. And for the same reason. For example, a message arrives from a fellow who claims to be qualified in all the basic stuff needed to maintain a VW engine, having owned his bug or bus for a number of years. In the message he provides a number of symptoms that make it clear the problem is worn valve guides, with a probability close to 100%, plus the fact that replacing the valve guides is a fairly common chore for the Volkswagen engine due to the small diameter of the valve stems and the fact air-cooled engines operate at a significantly higher temperature than their water-cooled cousins. Fortunately Volkswagen kept those things in mind when it designed the VW engine so that replacing the valve guides, which you'll need to do about every third valve job, is a straight-forward procedure, needed only a couple of additional tools.

With those things in mind I pointed the fellow toward the valve guide procedure, which I believe is fairly complete.

Unfortunately, the fellow had never done a valve job. And of course, he didn't have even the most most basic tool, the valve spring compressor, needed to dismantle the heads. His definition of Major Maintenance was replacing his clutch disk.

In the end, he bought a pair of 'rebuilt' heads from a the local 'expert' and took the first steps down the slippery slope that eventually lead to him getting rid of his Volkswagen.

Ditto for Flying Volkswagens, except that first step is liable to happen within a matter of hours rather than years. Why? Because a flying Volkswagen is liable to be operated for hours at a time at a level of output rarely seen in a bug or bus. The tricky bit here is the belief that all rpm's are the same; that running 3600 rpm in a plane will be the same as running 3600 rpm in a car. It isn't... unless the manifold pressure happens to be the same as well. The bottom line is that you can literally wear out a VW engine in a matter of hours.

Which isn't especially bad, assuming you understand what you are doing and keep a spare set of heads on hand.

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I'm a bit more circumspect nowadays, with people having assembled an engine from a kit of parts. Do you have a valve spring compressor? A rack to hold the removed valves? Do you have these foundation tools? Because if you don't, you'd better get them. You can buy them or make them but you absolutely can not do without them. These tools are the foundation of engine maintenace and to do without them is to build on a crooked foundation; things simply can not come out true.

This article shows a fixture for holding valves. These happen to be made of wood but you can make them from cardboard, assembled with duct tape, or scrap aluminum if you'd like a simple riveting project. But I like to work with wood and had some scrap handy....
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