This roller rocker business is frustrating. I had Harland Sharp Roller rockers (1.6) that got noisy when the car was hot (.47 lift cam) So, I changed out the lifters and push rods (just in case) and also put on Comp Cam Magnum Roller Rockers (also 1.6). Incredibly, the same result. There is NO valvetrain noise when cold, and it is fairly noisy when hot. I adjusted the rockers twice per the instructions. No change. I am now tempted to tighten the preload by another 1/4 or 1/2 turn. I would think that the push rod and valve stem would each "grow" a few thousandths when hot, but shouldn't the self adjusting nature of hydraulic lifters accommodate that change? But why is it QUIET when COLD???