Originally Posted by NJ-LE

Mine make very little noise ... more like a faint whirring. They're adjusted to zero + 3/8 of a turn. I do use the stock valve covers without any modifications. The last time I had them off I noticed a couple of the rockers (Crane Gold 1.6 S/A) had some of the anodizing rubbed off. No ridges or grooves could be felt nor any "gold dust" was found. The next time I take the covers off I'll "squeeze" the stiffening webs in those locations.