90 525i engine knock

i have a 90 525i i put a (new) used motor in the car back in january and now i have a terrible knocking noise it sounds like it is coming from the intake manifold . If i pull off one plug wire at at time i still have the noise all the time unlike when i had a broken rocker arm and when i pulled the spark plug wire off i was able to find out that was it. it is not the belts i feel the knocking right through the intake manifold but not through the valve cover. there is nothing broken in the valve cover or inside the intake manifold and the car idles like new. Oil has been changed every 3k miles since the motor has been installed and timing is great. The noise starts when you start the car and does not go away after the car warms up it sounds like a loud knocking like someone tapping on the intake manifold with a aluminum bat. and then it will go away for a few seconds and return again. It has fresh oil in it and new spark plugs also.

Any ideas would be greatly appriciated.

Thank you

I have a shat lifter in mine...does it sound like an old Chevy truck?

Chevy trucks are known for noisy lifters that is why I ask.

And does the sound increase with RPM'S?

the noise increases with sound until about 2500rpms and then it goes away completely until you let off the gas.

the car also does not make the noise while in 1,2,3,drive or reverse only in neutral and park.

Could it have something to do with your tranny since whenever your tranny is under load it doesn't make any noise?

My lifter makes the noise all the time so it's not that.

My 525i makes that kind of sound too. I've been told its normal and i've taken it to get looked at and everythings fine really. Stepping on the gas too quickly does it for me so just got to modulate the clutch or gas pedal and not heat up the engine too much. Our situations could be different but I do hope you find the problem =)