Several months ago I found the M30 front oil train banjo bolt lying in the valve train. I reinstalled the bolts with new locking washers and readjusted all the valves. Since then I have been living with noisy valves. I adjusted the valves three times but they still make noise. I looked at the lobes on the cam but I didn't see any damage. I have checked the noise with a stethoscope up and down the valve cover and it is noisier at the front of the engine where the banjo bolt fell out...which makes sense. Does the M30 have hydraulic lifters and if so can I use a cleaner to fix a sticky lifter? Does the M30 have solid lifters and there for I need to replace the eccentrics? I have a M30 in my 89 535i and it is as quiet as a sewing machine so I know the valve noise is a problem.