I didn't like the way the valve train sounded on my modified duke, so I decided to adjust the valve lash.
NOTE: This discussion doesn't apply to most dukes -- they don't have adjustable valves. But it does apply to Fiero V6 engines, and just about any other engine.
I found a
very good article on valve lash adjustment. From this, I learned some things I didn't know before. For example, unless you're doing the first adjustment after a rebuild, it's best to do the adjustment with the engine at operating temperature.
I also have a tip of my own. To easily turn the engine over while adjusting on a manual transmission car, jack one rear wheel just off the ground with a jack under the suspension. Put the transmission in the highest gear (5th for a 5-speed). Now you can turn the engine over by turning the jacked up wheel in the forward direction.
But the best way to do the adjusting, if you can run the engine with the valve cover(s) off, and control the oil mess, is to do it with the engine running. Fortunately, I have that SD4 valve cover on my duke, with the removable lid, which makes it easy, and with no mess.
If you have a noisy valve train, read the article. There's a lot of good info in it.
