I have a 1995 740iL BMW with a M62 series engine. I am getting a tapping noise in my lifter area on the drivers side of the engine. We thought we had collapsed lifters, but we replaced all 16 on that side.
I took it to the BMW dealer and all they could tell me is what i thought it was. They had no other ideas on what could be making this sound.
We checked the cranshaft and also pushed down on the rods while they in the engine. All of the springs compressed down, so the springs seem good.
When the engine runs it sounds like a deasel, and the sound is defenitley on the entire drivers side head bank.
Assuming it is valvetrain noise, if you can pull the valve cover and start the engine at idle, you can tell which one is the offender by placing the palm or heel of your hand on each valve or rocker or whatever (not sure what the valve gear is like on that). The one making the noise will be apparent by the amount of shock you feel. From there it's a matter of finding out why there is slack in the valvetrain.
Looks like this design uses an OHC, with cam lobes bearing against a follower. Lifter is at one end of follower, valve at the other.
Could be:
Bad lifter (but you've replaced them all. Bad cam lobe - worn past the range that the lifter can adjust for. In this case the cam & cam follower would show distress. Worn valve tip - mushroomed usually. Missing valve spring shim or steel insert between aluminum head and spring base. Damaged valve keeper? bad cam follower pivot bearing
Is there anything else in this valvetrain besides lifter-folower-valve? Hard to tell from the illustrations I'm finding.
If you find the offending valve/follower/cam lobe but can find nothing wrong with it, then you may be able to shim the lifter up enough to quiet it down. Usually the lifters sit in blind holes in the head. You'd remove the lifter, and drop a washer or something similar into the hole, then reassemble. Note that this is a last resort.
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