Trouble in the Shop

Reader Contribution by Richard Backus

I don’t consider my mechanical skills to be particularly well developed, despite the fact I once worked in a commercial shop. Four shops, actually: Two restoration outfits where I was nothing more than a grunt, but where I learned the critical lesson that restoration work is a hard way to make a living; a shady import repair shop where I was an apprentice mechanic, and where I learned the critical lesson that low-end repair shops pay poorly and support an environment even less enriching than the meager pay; and a seven-bay import/domestic repair shop where I was general manager, and where I learned the critical lesson that proper diagnosis, doing work well and charging fairly is harder than it sounds.

That last gig was the best of them all. My boss was my still good friend Pat Slimmer, a seasoned GM and Porsche/Audi-trained mechanic who also happens to be an artist, translating the creative energy required to be a truly good mechanic into sculptured steel. Pat’s artistic bent is a characteristic present in every good wrench I’ve ever met, and it makes sense when you think about. At its core, tearing things apart and putting them back together requires intelligence and imagination, the ability to look beyond the whole to its parts, and to understand the inter-relation of parts as they come off and go back on. Sometimes even the best manual won’t tell you how to slip a Lexus V6 timing chain tensioner into place, in a spot where there’s no room to work. You often have to imagine the process, relying on feel, intuition, and of course knowledge and experience.

I’m not an artist, which probably partly explains why I’m only an average mechanic. Or maybe it’s the other way around. Whichever, wrenching, depending upon what I’m working on, can be and often is a vexing affair, made worse by my seeming lack of simple math skills. That latter point came into sharp focus the other night, putting the engine back together on my 1983 Laverda RGS 1000 triple after a comprehensive top-end overhaul involving new pistons and rings, and a complete cylinder head rebuild including new stainless steel valves, bronze valve guides, new intake valve stem seals (Laverda didn’t use exhaust seals) and new valve springs.

To set valve clearances, the Laverda triple uses valve stem shim caps under cam-actuated buckets. The setup’s somewhat labor intensive, requiring camshaft removal any time clearances have to be reset. Determining the proper shim is a matter of measuring existing clearance, then subtracting or adding against the current shim. Valve clearance too tight? Use a thinner shim. Too loose? Thicker. Simple math, right? But a tired mind after a long day confused shim differences with clearances, resulting in incorrect calculations, resulting in me removing and installing the intake camshaft three times before I finally got it straight.

The frustration of all that extra wrenching set my panic meter soaring, convinced the constant tightening, loosening and retightening of the camshaft studs had to be stressing the stud threads. That same paranoid thinking convinced me the camshaft locating blocks must be getting crushed because of all this extra clamping and unclamping, and that I’d need to replace everything. Still certain I was jumping into a sewer of trouble, I set the exhaust cam clearances. It went perfectly. One shot, and it was done. Cool. Maybe everything’s OK after all, and the engine’s not going to self-destruct when I start it.

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