by noob » Fri Feb 06, 2015 2:12 pm
If its anything like the ZEX cams, they rattle quite a lot, its to do with how the cam lobes have been made......they have quite a harsh impact on the valves when they rotate, causing a lot of noise. I'm not too sure what sort of long term impact this has on the valve assembly, but I know it doesn't sound too great lol!
do you still have the stock valve springs or have you replaced them with a softer spring rate?
whenever your changing from a stock cam, you should really be looking into changing the valve springs to something a little softer......Supertech springs are supposed to be quite good for the D-series engines.